Rasmus Aamand; Thomas Dalsgaard; Yi Ching Lynn Ho; Arne Møller; Andreas Roepstorff; Torben E Lund A NO way to BOLD?: Dietary nitrate alters the hemodynamic response to visual stimulation Journal Article NeuroImage, 83 , pp. 397–407, 2013. Abstract | Links | BibTeX @article{Aamand2013,
title = {A NO way to BOLD?: Dietary nitrate alters the hemodynamic response to visual stimulation},
author = {Rasmus Aamand and Thomas Dalsgaard and Yi Ching Lynn Ho and Arne Møller and Andreas Roepstorff and Torben E Lund},
url = {http://dx.doi.org/10.1016/j.neuroimage.2013.06.069},
doi = {10.1016/j.neuroimage.2013.06.069},
year = {2013},
date = {2013-01-01},
journal = {NeuroImage},
volume = {83},
pages = {397--407},
publisher = {Elsevier Inc.},
abstract = {Neurovascular coupling links neuronal activity to vasodilation. Nitric oxide (NO) is a potent vasodilator, and in neurovascular coupling NO production from NO synthases plays an important role. However, another pathway for NO production also exists, namely the nitrate-nitrite-NO pathway. On this basis, we hypothesized that dietary nitrate (NO3-) could influence the brain's hemodynamic response to neuronal stimulation. In the present study, 20 healthy male participants were given either sodium nitrate (NaNO3) or sodium chloride (NaCl) (saline placebo) in a crossover study and were shown visual stimuli based on the retinotopic characteristics of the visual cortex. Our primary measure of the hemodynamic response was the blood oxygenation level dependent (BOLD) response measured with high-resolution functional magnetic resonance imaging (0.64×0.64×1.8mm) in the visual cortex. From this response, we made a direct estimate of key parameters characterizing the shape of the BOLD response (i.e. lag and amplitude). During elevated nitrate intake, corresponding to the nitrate content of a large plate of salad, both the hemodynamic lag and the BOLD amplitude decreased significantly (7.0±2% and 7.9±4%, respectively), and the variation across activated voxels of both measures decreased (12.3±4% and 15.3±7%, respectively). The baseline cerebral blood flow was not affected by nitrate. Ourexperiments demonstrate, for the first time, that dietary nitrate may modulate the local cerebral hemodynamic response to stimuli. A faster and smaller BOLD response, with less variation across local cortex, is consistent with an enhanced hemodynamic coupling during elevated nitrate intake. These findings suggest that dietary patterns, via the nitrate-nitrite-NO pathway, may be a potential way to affect key properties of neurovascular coupling. This could have major clinical implications, which remain to be explored.},
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Neurovascular coupling links neuronal activity to vasodilation. Nitric oxide (NO) is a potent vasodilator, and in neurovascular coupling NO production from NO synthases plays an important role. However, another pathway for NO production also exists, namely the nitrate-nitrite-NO pathway. On this basis, we hypothesized that dietary nitrate (NO3-) could influence the brain's hemodynamic response to neuronal stimulation. In the present study, 20 healthy male participants were given either sodium nitrate (NaNO3) or sodium chloride (NaCl) (saline placebo) in a crossover study and were shown visual stimuli based on the retinotopic characteristics of the visual cortex. Our primary measure of the hemodynamic response was the blood oxygenation level dependent (BOLD) response measured with high-resolution functional magnetic resonance imaging (0.64×0.64×1.8mm) in the visual cortex. From this response, we made a direct estimate of key parameters characterizing the shape of the BOLD response (i.e. lag and amplitude). During elevated nitrate intake, corresponding to the nitrate content of a large plate of salad, both the hemodynamic lag and the BOLD amplitude decreased significantly (7.0±2% and 7.9±4%, respectively), and the variation across activated voxels of both measures decreased (12.3±4% and 15.3±7%, respectively). The baseline cerebral blood flow was not affected by nitrate. Ourexperiments demonstrate, for the first time, that dietary nitrate may modulate the local cerebral hemodynamic response to stimuli. A faster and smaller BOLD response, with less variation across local cortex, is consistent with an enhanced hemodynamic coupling during elevated nitrate intake. These findings suggest that dietary patterns, via the nitrate-nitrite-NO pathway, may be a potential way to affect key properties of neurovascular coupling. This could have major clinical implications, which remain to be explored. |
Rasmus Aamand; Yi-Ching Lynn Ho; Thomas Dalsgaard; Andreas Roepstorff; Torben E Lund Dietary nitrate facilitates an acetazolamide-induced increase in cerebral blood flow during visual stimulation Journal Article Journal of Applied Physiology, 116 (3), pp. 267–273, 2014. Abstract | Links | BibTeX @article{Aamand2014,
title = {Dietary nitrate facilitates an acetazolamide-induced increase in cerebral blood flow during visual stimulation},
author = {Rasmus Aamand and Yi-Ching Lynn Ho and Thomas Dalsgaard and Andreas Roepstorff and Torben E Lund},
url = {http://jap.physiology.org/cgi/doi/10.1152/japplphysiol.00797.2013},
doi = {10.1152/japplphysiol.00797.2013},
year = {2014},
date = {2014-01-01},
journal = {Journal of Applied Physiology},
volume = {116},
number = {3},
pages = {267--273},
abstract = {The carbonic anhydrase (CA) inhibitor acetazolamide (AZ) is used routinely to estimate cerebrovascular reserve capacity in patients, as it reliably increases cerebral blood flow (CBF). However, the mechanism by which AZ accomplishes this CBF increase is not entirely understood. We recently discovered that CA can produce nitric oxide (NO) from nitrite, and that AZ enhances this NO production in vitro. In fact, this interaction between AZ and CA accounted for a large part of AZ's vasodilatory action, which fits well with the known vasodilatory potency of NO. The present study aimed to assess whether AZ acts similarly in vivo in the human cerebrovascular system. Hence, we increased or minimized the dietary intake of nitrate in 20 healthy male participants, showed them a full-field flickering dartboard, and measured their CBF response to this visual stimulus with arterial spin labeling. Doing so, we found a significant positive interaction between the dietary intake of nitrate and the CBF modulation afforded by AZ during visual stimulation. In addition, but contrary to studies conducted in elderly participants, we report no effect of nitrate intake on resting CBF in healthy human participants. The present study provides in vivo support for an enhancing effect of AZ on the NO production from nitrite catalyzed by CA in the cerebrovascular system. Furthermore, our results, in combination with the results of other groups, indicate that nitrate may have significant importance to vascular function when the cerebrovascular system is challenged by age or disease.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The carbonic anhydrase (CA) inhibitor acetazolamide (AZ) is used routinely to estimate cerebrovascular reserve capacity in patients, as it reliably increases cerebral blood flow (CBF). However, the mechanism by which AZ accomplishes this CBF increase is not entirely understood. We recently discovered that CA can produce nitric oxide (NO) from nitrite, and that AZ enhances this NO production in vitro. In fact, this interaction between AZ and CA accounted for a large part of AZ's vasodilatory action, which fits well with the known vasodilatory potency of NO. The present study aimed to assess whether AZ acts similarly in vivo in the human cerebrovascular system. Hence, we increased or minimized the dietary intake of nitrate in 20 healthy male participants, showed them a full-field flickering dartboard, and measured their CBF response to this visual stimulus with arterial spin labeling. Doing so, we found a significant positive interaction between the dietary intake of nitrate and the CBF modulation afforded by AZ during visual stimulation. In addition, but contrary to studies conducted in elderly participants, we report no effect of nitrate intake on resting CBF in healthy human participants. The present study provides in vivo support for an enhancing effect of AZ on the NO production from nitrite catalyzed by CA in the cerebrovascular system. Furthermore, our results, in combination with the results of other groups, indicate that nitrate may have significant importance to vascular function when the cerebrovascular system is challenged by age or disease. |
Rick A Adams; Markus Bauer; Dimitris Pinotsis; Karl J Friston Dynamic causal modelling of eye movements during pursuit: Confirming precision-encoding in V1 using MEG Journal Article Neuroimage, 132 , pp. 175–189, 2016. Abstract | Links | BibTeX @article{Adams2016,
title = {Dynamic causal modelling of eye movements during pursuit: Confirming precision-encoding in V1 using MEG},
author = {Rick A Adams and Markus Bauer and Dimitris Pinotsis and Karl J Friston},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.02.055},
doi = {10.1016/j.neuroimage.2016.02.055},
year = {2016},
date = {2016-01-01},
journal = {Neuroimage},
volume = {132},
pages = {175--189},
publisher = {The Authors},
abstract = {This paper shows that it is possible to estimate the subjective precision (inverse variance) of Bayesian beliefs during oculomotor pursuit. Subjects viewed a sinusoidal target, with or without random fluctuations in its motion. Eye trajectories and magnetoencephalographic (MEG) data were recorded concurrently. The target was periodically occluded, such that its reappearance caused a visual evoked response field (ERF). Dynamic causal modelling (DCM) was used to fit models of eye trajectories and the ERFs. The DCM for pursuit was based on predictive coding and active inference, and predicts subjects' eye movements based on their (subjective) Bayesian beliefs about target (and eye) motion. The precisions of these hierarchical beliefs can be inferred from behavioural (pursuit) data. The DCM for MEG data used an established biophysical model of neuronal activity that includes parameters for the gain of superficial pyramidal cells, which is thought to encode precision at the neuronal level. Previous studies (using DCM of pursuit data) suggest that noisy target motion increases subjective precision at the sensory level: i.e., subjects attend more to the target's sensory attributes. We compared (noisy motion-induced) changes in the synaptic gain based on the modelling of MEG data to changes in subjective precision estimated using the pursuit data. We demonstrate that imprecise target motion increases the gain of superficial pyramidal cells in V1 (across subjects). Furthermore, increases in sensory precision – inferred by our behavioural DCM – correlate with the increase in gain in V1, across subjects. This is a step towards a fully integrated model of brain computations, cortical responses and behaviour that may provide a useful clinical tool in conditions like schizophrenia.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper shows that it is possible to estimate the subjective precision (inverse variance) of Bayesian beliefs during oculomotor pursuit. Subjects viewed a sinusoidal target, with or without random fluctuations in its motion. Eye trajectories and magnetoencephalographic (MEG) data were recorded concurrently. The target was periodically occluded, such that its reappearance caused a visual evoked response field (ERF). Dynamic causal modelling (DCM) was used to fit models of eye trajectories and the ERFs. The DCM for pursuit was based on predictive coding and active inference, and predicts subjects' eye movements based on their (subjective) Bayesian beliefs about target (and eye) motion. The precisions of these hierarchical beliefs can be inferred from behavioural (pursuit) data. The DCM for MEG data used an established biophysical model of neuronal activity that includes parameters for the gain of superficial pyramidal cells, which is thought to encode precision at the neuronal level. Previous studies (using DCM of pursuit data) suggest that noisy target motion increases subjective precision at the sensory level: i.e., subjects attend more to the target's sensory attributes. We compared (noisy motion-induced) changes in the synaptic gain based on the modelling of MEG data to changes in subjective precision estimated using the pursuit data. We demonstrate that imprecise target motion increases the gain of superficial pyramidal cells in V1 (across subjects). Furthermore, increases in sensory precision – inferred by our behavioural DCM – correlate with the increase in gain in V1, across subjects. This is a step towards a fully integrated model of brain computations, cortical responses and behaviour that may provide a useful clinical tool in conditions like schizophrenia. |
C J Aine; H J Bockholt; J R Bustillo; J M Cañive; A Caprihan; C Gasparovic; F M Hanlon; J M Houck; R E Jung; J Lauriello; J Liu; A R Mayer; N I Perrone-Bizzozero; S Posse; J M Stephen; J A Turner; V P Clark; Vince D Calhoun Multimodal neuroimaging in schizophrenia: Description and dissemination Journal Article Neuroinformatics, 15 (4), pp. 343–364, 2017. Abstract | Links | BibTeX @article{Aine2017,
title = {Multimodal neuroimaging in schizophrenia: Description and dissemination},
author = {C J Aine and H J Bockholt and J R Bustillo and J M Ca{ñ}ive and A Caprihan and C Gasparovic and F M Hanlon and J M Houck and R E Jung and J Lauriello and J Liu and A R Mayer and N I Perrone-Bizzozero and S Posse and J M Stephen and J A Turner and V P Clark and Vince D Calhoun},
doi = {10.1007/s12021-017-9338-9},
year = {2017},
date = {2017-01-01},
journal = {Neuroinformatics},
volume = {15},
number = {4},
pages = {343--364},
publisher = {Neuroinformatics},
abstract = {In this paper we describe an open-access collection ofmultimodal neuroimaging data in schizophrenia for release to the community. Data were acquired from approximately 100 patients with schizophrenia and 100 age-matched controls during rest as well as several task activation paradigms targeting a hierarchy of cognitive constructs. Neuroimaging data include structural MRI, functional MRI, diffusion MRI, MR spectroscopic imaging, and magnetoencephalography. For three of the hypothesis-driven projects, task activation paradigms were acquired on subsets of~200 volunteers which examined a range of sensory and cognitive processes (e.g., auditory sensory gating, auditory/visual multisensory integration, visual transverse patterning). Neuropsychological data were also acquired and genetic material via saliva samples were collected from most of the participants and have been typed for both genome-wide polymorphism data as well as genome-wide methylation data. Some results are also present- ed from the individual studies as well as from our data-driven multimodal analyses (e.g., multimodal examinations of network structure and network dynamics and multitask fMRI data analysis across projects). All data will be released through the Mind Research Network's collaborative informatics and neuroimaging suite (COINS).},
keywords = {},
pubstate = {published},
tppubtype = {article}
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In this paper we describe an open-access collection ofmultimodal neuroimaging data in schizophrenia for release to the community. Data were acquired from approximately 100 patients with schizophrenia and 100 age-matched controls during rest as well as several task activation paradigms targeting a hierarchy of cognitive constructs. Neuroimaging data include structural MRI, functional MRI, diffusion MRI, MR spectroscopic imaging, and magnetoencephalography. For three of the hypothesis-driven projects, task activation paradigms were acquired on subsets of~200 volunteers which examined a range of sensory and cognitive processes (e.g., auditory sensory gating, auditory/visual multisensory integration, visual transverse patterning). Neuropsychological data were also acquired and genetic material via saliva samples were collected from most of the participants and have been typed for both genome-wide polymorphism data as well as genome-wide methylation data. Some results are also present- ed from the individual studies as well as from our data-driven multimodal analyses (e.g., multimodal examinations of network structure and network dynamics and multitask fMRI data analysis across projects). All data will be released through the Mind Research Network's collaborative informatics and neuroimaging suite (COINS). |
Sara Ajina; Christopher Kennard; Geraint Rees; Holly Bridge Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex Journal Article Brain, 138 (1), pp. 164–178, 2015. Abstract | Links | BibTeX @article{Ajina2015,
title = {Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex},
author = {Sara Ajina and Christopher Kennard and Geraint Rees and Holly Bridge},
doi = {10.1093/brain/awu328},
year = {2015},
date = {2015-01-01},
journal = {Brain},
volume = {138},
number = {1},
pages = {164--178},
abstract = {Motion area V5/MT+ shows a variety of characteristic visual responses, often linked to perception, which are heavily influenced by its rich connectivity with the primary visual cortex (V1). This human motion area also receives a number of inputs from other visual regions, including direct subcortical connections and callosal connections with the contralateral hemisphere. Little is currently known about such alternative inputs to V5/MT+ and how they may drive and influence its activity. Using functional magnetic resonance imaging, the response of human V5/MT+ to increasing the proportion of coherent motion was measured in seven patients with unilateral V1 damage acquired during adulthood, and a group of healthy age-matched controls. When V1 was damaged, the typical V5/MT+ response to increasing coherence was lost. Rather, V5/MT+ in patients showed a negative trend with coherence that was similar to coherence-related activity in V1 of healthy control subjects. This shift to a response-pattern more typical of early visual cortex suggests that in the absence of V1, V5/MT+ activity may be shaped by similar direct subcortical input. This is likely to reflect intact residual pathways rather than a change in connectivity, and has important implications for blindsight function. It also confirms predictions that V1 is critically involved in normal V5/MT+ global motion processing, consistent with a convergent model of V1 input to V5/MT+. Historically, most attempts to model cortical visual responses do not consider the contribution of direct subcortical inputs that may bypass striate cortex, such as input to V5/MT+. We have shown that the signal change driven by these non-striate pathways can be measured, and suggest that models of the intact visual system may benefit from considering their contribution.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Motion area V5/MT+ shows a variety of characteristic visual responses, often linked to perception, which are heavily influenced by its rich connectivity with the primary visual cortex (V1). This human motion area also receives a number of inputs from other visual regions, including direct subcortical connections and callosal connections with the contralateral hemisphere. Little is currently known about such alternative inputs to V5/MT+ and how they may drive and influence its activity. Using functional magnetic resonance imaging, the response of human V5/MT+ to increasing the proportion of coherent motion was measured in seven patients with unilateral V1 damage acquired during adulthood, and a group of healthy age-matched controls. When V1 was damaged, the typical V5/MT+ response to increasing coherence was lost. Rather, V5/MT+ in patients showed a negative trend with coherence that was similar to coherence-related activity in V1 of healthy control subjects. This shift to a response-pattern more typical of early visual cortex suggests that in the absence of V1, V5/MT+ activity may be shaped by similar direct subcortical input. This is likely to reflect intact residual pathways rather than a change in connectivity, and has important implications for blindsight function. It also confirms predictions that V1 is critically involved in normal V5/MT+ global motion processing, consistent with a convergent model of V1 input to V5/MT+. Historically, most attempts to model cortical visual responses do not consider the contribution of direct subcortical inputs that may bypass striate cortex, such as input to V5/MT+. We have shown that the signal change driven by these non-striate pathways can be measured, and suggest that models of the intact visual system may benefit from considering their contribution. |
Sara Ajina; Geraint Rees; Christopher Kennard; Holly Bridge Abnormal contrast responses in the extrastriate cortex of blindsight patients Journal Article Journal of Neuroscience, 35 (21), pp. 8201–8213, 2015. Abstract | Links | BibTeX @article{Ajina2015b,
title = {Abnormal contrast responses in the extrastriate cortex of blindsight patients},
author = {Sara Ajina and Geraint Rees and Christopher Kennard and Holly Bridge},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.3075-14.2015},
doi = {10.1523/JNEUROSCI.3075-14.2015},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neuroscience},
volume = {35},
number = {21},
pages = {8201--8213},
abstract = {When the human primary visual cortex (V1) is damaged, the dominant geniculo-striate pathway can no longer convey visual information to the occipital cortex. However, many patients with such damage retain some residual visual function that must rely on an alternative pathway directly to extrastriate occipital regions. This residual vision is most robust for moving stimuli, suggesting a role for motion area hMT+. However, residual vision also requires high-contrast stimuli, which is inconsistent with hMT+ sensitivity to contrast in which even low-contrast levels elicit near-maximal neural activation. We sought to investigate this discrepancy by measuring behavioral and neural responses to increasing contrast in patients with V1 damage. Eight patients underwent behavioral testing and functional magnetic resonance imaging to record contrast sensitivity in hMT+ of their damaged hemisphere, using Gabor stimuli with a spatial frequency of 1 cycle/degrees. The responses from hMT+ of the blind hemisphere were compared with hMT+ and V1 responses in the sighted hemisphere of patients and a group of age-matched controls. Unlike hMT+, neural responses in V1 tend to increase linearly with increasing contrast, likely reflecting a dominant parvocellular channel input. Across all patients, the responses in hMT+ of the blind hemisphere no longer showed early saturation but increased linearly with contrast. Given the spatiotemporal parameters used in this study and the known direct subcortical projections from the koniocellular layers of the lateral geniculate nucleus to hMT+, we propose that this altered contrast sensitivity in hMT+ could be consistent with input from the koniocellular pathway.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
When the human primary visual cortex (V1) is damaged, the dominant geniculo-striate pathway can no longer convey visual information to the occipital cortex. However, many patients with such damage retain some residual visual function that must rely on an alternative pathway directly to extrastriate occipital regions. This residual vision is most robust for moving stimuli, suggesting a role for motion area hMT+. However, residual vision also requires high-contrast stimuli, which is inconsistent with hMT+ sensitivity to contrast in which even low-contrast levels elicit near-maximal neural activation. We sought to investigate this discrepancy by measuring behavioral and neural responses to increasing contrast in patients with V1 damage. Eight patients underwent behavioral testing and functional magnetic resonance imaging to record contrast sensitivity in hMT+ of their damaged hemisphere, using Gabor stimuli with a spatial frequency of 1 cycle/degrees. The responses from hMT+ of the blind hemisphere were compared with hMT+ and V1 responses in the sighted hemisphere of patients and a group of age-matched controls. Unlike hMT+, neural responses in V1 tend to increase linearly with increasing contrast, likely reflecting a dominant parvocellular channel input. Across all patients, the responses in hMT+ of the blind hemisphere no longer showed early saturation but increased linearly with contrast. Given the spatiotemporal parameters used in this study and the known direct subcortical projections from the koniocellular layers of the lateral geniculate nucleus to hMT+, we propose that this altered contrast sensitivity in hMT+ could be consistent with input from the koniocellular pathway. |
Elaine J Anderson; Marc S Tibber; Sam D Schwarzkopf; Sukhwinder S Shergill; Emilio Fernandez-Egea; Geraint Rees; Steven C Dakin Visual population receptive fields in people with schizophrenia have reduced inhibitory surrounds Journal Article Journal of Neuroscience, 37 (6), pp. 1546–1556, 2017. Abstract | Links | BibTeX @article{Anderson2017,
title = {Visual population receptive fields in people with schizophrenia have reduced inhibitory surrounds},
author = {Elaine J Anderson and Marc S Tibber and Sam D Schwarzkopf and Sukhwinder S Shergill and Emilio Fernandez-Egea and Geraint Rees and Steven C Dakin},
url = {http://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.3620-15.2016},
doi = {10.1523/JNEUROSCI.3620-15.2016},
year = {2017},
date = {2017-01-01},
journal = {Journal of Neuroscience},
volume = {37},
number = {6},
pages = {1546--1556},
abstract = {People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However, differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reportedin vivoHere, we probed the neural basis of these deficits using fMRI and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a difference-of-Gaussian model to capture the center-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex, as well as a reduction in size and depth of the inhibitory surround in V1, V2, and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However, differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reportedin vivoHere, we probed the neural basis of these deficits using fMRI and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a difference-of-Gaussian model to capture the center-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex, as well as a reduction in size and depth of the inhibitory surround in V1, V2, and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ. |
Jamila Andoh; Reiko Matsushita; Robert J Zatorre Asymmetric interhemispheric transfer in the auditory network: Evidence from TMS, resting-state fMRI, and diffusion imaging Journal Article Journal of Neuroscience, 43 (43), pp. 14602–14611, 2015. Abstract | Links | BibTeX @article{Andoh2015,
title = {Asymmetric interhemispheric transfer in the auditory network: Evidence from TMS, resting-state fMRI, and diffusion imaging},
author = {Jamila Andoh and Reiko Matsushita and Robert J Zatorre},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.2333-15.2015},
doi = {10.1523/JNEUROSCI.2333-15.2015},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neuroscience},
volume = {43},
number = {43},
pages = {14602--14611},
abstract = {Hemispheric asymmetries in human auditory cortical function and structure are still highly debated. Brain stimulation approaches can complement correlational techniques by uncovering causal influences. Previous studies have shown asymmetrical effects of transcranial magnetic stimulation (TMS) on task performance, but it is unclear whether these effects are task-specific or reflect intrinsic network properties. To test how modulation of auditory cortex (AC) influences functional networks and whether this influence is asymmetrical, the present study measured resting-state fMRI connectivity networks in 17 healthy volunteers before and immediately after TMS (continuous theta burst stimulation) to the left or right AC, and the vertex as a control. We also examined the relationship between TMS-induced interhemispheric signal propagation and anatomical properties of callosal auditory fibers as measured with diffusion-weighted MRI. We found that TMS to the right AC, but not the left, resulted in widespread connectivity decreases in auditory- and motor-related networks in the resting state. Individual differences in the degree of change in functional connectivity between auditory cortices after TMS applied over the right AC were negatively related to the volume of callosal auditory fibers. The findings show that TMS-induced network modulation occurs, even in the absence of an explicit task, and that the magnitude of the effect differs across individuals as a function of callosal structure, supporting a role for the corpus callosum in mediating functional asymmetry. The findings support theoretical models emphasizing hemispheric differences in network organization and are of practical significance in showing that brain stimulation studies need to take network-level effects into account.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Hemispheric asymmetries in human auditory cortical function and structure are still highly debated. Brain stimulation approaches can complement correlational techniques by uncovering causal influences. Previous studies have shown asymmetrical effects of transcranial magnetic stimulation (TMS) on task performance, but it is unclear whether these effects are task-specific or reflect intrinsic network properties. To test how modulation of auditory cortex (AC) influences functional networks and whether this influence is asymmetrical, the present study measured resting-state fMRI connectivity networks in 17 healthy volunteers before and immediately after TMS (continuous theta burst stimulation) to the left or right AC, and the vertex as a control. We also examined the relationship between TMS-induced interhemispheric signal propagation and anatomical properties of callosal auditory fibers as measured with diffusion-weighted MRI. We found that TMS to the right AC, but not the left, resulted in widespread connectivity decreases in auditory- and motor-related networks in the resting state. Individual differences in the degree of change in functional connectivity between auditory cortices after TMS applied over the right AC were negatively related to the volume of callosal auditory fibers. The findings show that TMS-induced network modulation occurs, even in the absence of an explicit task, and that the magnitude of the effect differs across individuals as a function of callosal structure, supporting a role for the corpus callosum in mediating functional asymmetry. The findings support theoretical models emphasizing hemispheric differences in network organization and are of practical significance in showing that brain stimulation studies need to take network-level effects into account. |
J Andoh; M Ferreira; I R Leppert; R Matsushita; B Pike; R J Zatorre How restful is it with all that noise? Comparison of Interleaved silent steady state (ISSS) and conventional imaging in resting-state fMRI Journal Article NeuroImage, 147 , pp. 726–735, 2017. Abstract | Links | BibTeX @article{Andoh2017,
title = {How restful is it with all that noise? Comparison of Interleaved silent steady state (ISSS) and conventional imaging in resting-state fMRI},
author = {J Andoh and M Ferreira and I R Leppert and R Matsushita and B Pike and R J Zatorre},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.11.065},
doi = {10.1016/j.neuroimage.2016.11.065},
year = {2017},
date = {2017-01-01},
journal = {NeuroImage},
volume = {147},
pages = {726--735},
publisher = {Elsevier},
abstract = {Resting-state fMRI studies have become very important in cognitive neuroscience because they are able to identify BOLD fluctuations in brain circuits involved in motor, cognitive, or perceptual processes without the use of an explicit task. Such approaches have been fruitful when applied to various disordered populations, or to children or the elderly. However, insufficient attention has been paid to the consequences of the loud acoustic scanner noise associated with conventional fMRI acquisition, which could be an important confounding factor affecting auditory and/or cognitive networks in resting-state fMRI. Several approaches have been developed to mitigate the effects of acoustic noise on fMRI signals, including sparse sampling protocols and interleaved silent steady state (ISSS) acquisition methods, the latter being used only for task-based fMRI. Here, we developed an ISSS protocol for resting-state fMRI (rs-ISSS) consisting of rapid acquisition of a set of echo planar imaging volumes following each silent period, during which the steady state longitudinal magnetization was maintained with a train of relatively silent slice-selective excitation pulses. We evaluated the test-retest reliability of intensity and spatial extent of connectivity networks of fMRI BOLD signal across three different days for rs-ISSS and compared it with a standard resting-state fMRI (rs-STD). We also compared the strength and distribution of connectivity networks between rs-ISSS and rs-STD. We found that both rs-ISSS and rs-STD showed high reproducibility of fMRI signal across days. In addition, rs-ISSS showed a more robust pattern of functional connectivity within the somatosensory and motor networks, as well as an auditory network compared with rs-STD. An increased connectivity between the default mode network and the language network and with the anterior cingulate cortex (ACC) network was also found for rs-ISSS compared with rs-STD. Finally, region of interest analysis showed higher interhemispheric connectivity in Heschl's gyri in rs-ISSS compared with rs-STD, with lower variability across days. The present findings suggest that rs-ISSS may be advantageous for detecting network connectivity in a less noisy environment, and that resting-state studies carried out with standard scanning protocols should consider the potential effects of loud noise on the measured networks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Resting-state fMRI studies have become very important in cognitive neuroscience because they are able to identify BOLD fluctuations in brain circuits involved in motor, cognitive, or perceptual processes without the use of an explicit task. Such approaches have been fruitful when applied to various disordered populations, or to children or the elderly. However, insufficient attention has been paid to the consequences of the loud acoustic scanner noise associated with conventional fMRI acquisition, which could be an important confounding factor affecting auditory and/or cognitive networks in resting-state fMRI. Several approaches have been developed to mitigate the effects of acoustic noise on fMRI signals, including sparse sampling protocols and interleaved silent steady state (ISSS) acquisition methods, the latter being used only for task-based fMRI. Here, we developed an ISSS protocol for resting-state fMRI (rs-ISSS) consisting of rapid acquisition of a set of echo planar imaging volumes following each silent period, during which the steady state longitudinal magnetization was maintained with a train of relatively silent slice-selective excitation pulses. We evaluated the test-retest reliability of intensity and spatial extent of connectivity networks of fMRI BOLD signal across three different days for rs-ISSS and compared it with a standard resting-state fMRI (rs-STD). We also compared the strength and distribution of connectivity networks between rs-ISSS and rs-STD. We found that both rs-ISSS and rs-STD showed high reproducibility of fMRI signal across days. In addition, rs-ISSS showed a more robust pattern of functional connectivity within the somatosensory and motor networks, as well as an auditory network compared with rs-STD. An increased connectivity between the default mode network and the language network and with the anterior cingulate cortex (ACC) network was also found for rs-ISSS compared with rs-STD. Finally, region of interest analysis showed higher interhemispheric connectivity in Heschl's gyri in rs-ISSS compared with rs-STD, with lower variability across days. The present findings suggest that rs-ISSS may be advantageous for detecting network connectivity in a less noisy environment, and that resting-state studies carried out with standard scanning protocols should consider the potential effects of loud noise on the measured networks. |
Serguei V Astafiev; Kristina L Zinn; Gordon L Shulman; Maurizio Corbetta Exploring the physiological correlates of chronic mild traumatic brain injury symptoms Journal Article NeuroImage: Clinical, 11 , pp. 10–19, 2016. Abstract | Links | BibTeX @article{Astafiev2016,
title = {Exploring the physiological correlates of chronic mild traumatic brain injury symptoms},
author = {Serguei V Astafiev and Kristina L Zinn and Gordon L Shulman and Maurizio Corbetta},
url = {https://www.sciencedirect.com/science/article/pii/S2213158216300043},
doi = {10.1016/j.nicl.2016.01.004},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage: Clinical},
volume = {11},
pages = {10--19},
publisher = {Elsevier},
abstract = {We report on the results of a multimodal imaging study involving behavioral assessments, evoked and resting-state BOLD fMRI, and DTI in chronic mTBI subjects. We found that larger task-evoked BOLD activity in the MT+/LO region in extra-striate visual cortex correlated with mTBI and PTSD symptoms, especially light sensitivity. Moreover, higher FA values near the left optic radiation (OR) were associated with both light sensitivity and higher BOLD activity in the MT+/LO region. The MT+/LO region was localized as a region of abnormal functional connectivity with central white matter regions previously found to have abnormal physiological signals during visual eye movement tracking (Astafiev et al., 2015). We conclude that mTBI symptoms and light sensitivity may be related to excessive responsiveness of visual cortex to sensory stimuli. This abnormal sensitivity may be related to chronic remodeling of white matter visual pathways acutely injured.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on the results of a multimodal imaging study involving behavioral assessments, evoked and resting-state BOLD fMRI, and DTI in chronic mTBI subjects. We found that larger task-evoked BOLD activity in the MT+/LO region in extra-striate visual cortex correlated with mTBI and PTSD symptoms, especially light sensitivity. Moreover, higher FA values near the left optic radiation (OR) were associated with both light sensitivity and higher BOLD activity in the MT+/LO region. The MT+/LO region was localized as a region of abnormal functional connectivity with central white matter regions previously found to have abnormal physiological signals during visual eye movement tracking (Astafiev et al., 2015). We conclude that mTBI symptoms and light sensitivity may be related to excessive responsiveness of visual cortex to sensory stimuli. This abnormal sensitivity may be related to chronic remodeling of white matter visual pathways acutely injured. |
Ryszard Auksztulewicz; Karl Friston Attentional enhancement of auditory mismatch responses: A DCM/MEG study Journal Article Cerebral Cortex, 25 (11), pp. 4273–4283, 2015. Abstract | Links | BibTeX @article{Auksztulewicz2015,
title = {Attentional enhancement of auditory mismatch responses: A DCM/MEG study},
author = {Ryszard Auksztulewicz and Karl Friston},
doi = {10.1093/cercor/bhu323},
year = {2015},
date = {2015-01-01},
journal = {Cerebral Cortex},
volume = {25},
number = {11},
pages = {4273--4283},
abstract = {Despite similar behavioral effects, attention and expectation influence evoked responses differently: Attention typically enhances event-related responses, whereas expectation reduces them. This dissociation has been reconciled under predictive coding, where prediction errors are weighted by precision associated with attentional modulation. Here, we tested the predictive coding account of attention and expectation using magnetoencephalography and modeling. Temporal attention and sensory expectation were orthogonally manipulated in an auditory mismatch paradigm, revealing opposing effects on evoked response amplitude. Mismatch negativity (MMN) was enhanced by attention, speaking against its supposedly pre-attentive nature. This interaction effect was modeled in a canonical microcircuit using dynamic causal modeling, comparing models with modulation of extrinsic and intrinsic connectivity at different levels of the auditory hierarchy. While MMN was explained by recursive interplay of sensory predictions and prediction errors, attention was linked to the gain of inhibitory interneurons, consistent with its modulation of sensory precision.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Despite similar behavioral effects, attention and expectation influence evoked responses differently: Attention typically enhances event-related responses, whereas expectation reduces them. This dissociation has been reconciled under predictive coding, where prediction errors are weighted by precision associated with attentional modulation. Here, we tested the predictive coding account of attention and expectation using magnetoencephalography and modeling. Temporal attention and sensory expectation were orthogonally manipulated in an auditory mismatch paradigm, revealing opposing effects on evoked response amplitude. Mismatch negativity (MMN) was enhanced by attention, speaking against its supposedly pre-attentive nature. This interaction effect was modeled in a canonical microcircuit using dynamic causal modeling, comparing models with modulation of extrinsic and intrinsic connectivity at different levels of the auditory hierarchy. While MMN was explained by recursive interplay of sensory predictions and prediction errors, attention was linked to the gain of inhibitory interneurons, consistent with its modulation of sensory precision. |
Mariana Babo-Rebelo; Craig G Richter; Catherine Tallon-Baudry Neural responses to heartbeats in the default network encode the self in spontaneous thoughts Journal Article Journal of Neuroscience, 36 (30), pp. 7829–7840, 2016. Abstract | Links | BibTeX @article{Babo-Rebelo2016,
title = {Neural responses to heartbeats in the default network encode the self in spontaneous thoughts},
author = {Mariana Babo-Rebelo and Craig G Richter and Catherine Tallon-Baudry},
url = {http://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.0262-16.2016},
doi = {10.1523/JNEUROSCI.0262-16.2016},
year = {2016},
date = {2016-01-01},
journal = {Journal of Neuroscience},
volume = {36},
number = {30},
pages = {7829--7840},
abstract = {The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered. When interrupted by a visual stimulus at random intervals, participants scored the self-relatedness of the interrupted thought. They evaluated their involvement as the first-person perspective subject or agent in the thought ("I"), and on another scale to what degree they were thinking about themselves ("Me"). During the interrupted thought, neural responses to heartbeats in two regions of the DN, the ventral precuneus and the ventromedial prefrontal cortex, covaried, respectively, with the "I" and the "Me" dimensions of the self, even at the single-trial level. No covariation between self-relatedness and peripheral autonomic measures (heart rate, heart rate variability, pupil diameter, electrodermal activity, respiration rate, and phase) or alpha power was observed. Our results reveal a direct link between selfhood and neural responses to heartbeats in the DN and thus directly support theories grounding selfhood in the neural monitoring of visceral inputs. More generally, the tight functional coupling between self-related processing and cardiac monitoring observed here implies that, even in the absence of measured changes in peripheral bodily measures, physiological and cognitive functions have to be considered jointly in the DN.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered. When interrupted by a visual stimulus at random intervals, participants scored the self-relatedness of the interrupted thought. They evaluated their involvement as the first-person perspective subject or agent in the thought ("I"), and on another scale to what degree they were thinking about themselves ("Me"). During the interrupted thought, neural responses to heartbeats in two regions of the DN, the ventral precuneus and the ventromedial prefrontal cortex, covaried, respectively, with the "I" and the "Me" dimensions of the self, even at the single-trial level. No covariation between self-relatedness and peripheral autonomic measures (heart rate, heart rate variability, pupil diameter, electrodermal activity, respiration rate, and phase) or alpha power was observed. Our results reveal a direct link between selfhood and neural responses to heartbeats in the DN and thus directly support theories grounding selfhood in the neural monitoring of visceral inputs. More generally, the tight functional coupling between self-related processing and cardiac monitoring observed here implies that, even in the absence of measured changes in peripheral bodily measures, physiological and cognitive functions have to be considered jointly in the DN. |
Dominik R Bach; Nicholas Furl; Gareth Barnes; Raymond J Dolan Sustained magnetic responses in temporal cortex reflect instantaneous significance of approaching and receding sounds Journal Article PLoS ONE, 10 (7), pp. 1–13, 2015. Abstract | Links | BibTeX @article{Bach2015,
title = {Sustained magnetic responses in temporal cortex reflect instantaneous significance of approaching and receding sounds},
author = {Dominik R Bach and Nicholas Furl and Gareth Barnes and Raymond J Dolan},
doi = {10.1371/journal.pone.0134060},
year = {2015},
date = {2015-01-01},
journal = {PLoS ONE},
volume = {10},
number = {7},
pages = {1--13},
abstract = {Rising sound intensity often signals an approaching sound source and can serve as a powerful warning cue, eliciting phasic attention, perception biases and emotional responses. How the evaluation of approaching sounds unfolds over time remains elusive. Here, we capitalised on the temporal resolution of magnetoencephalograpy (MEG) to investigate in humans a dynamic encoding of perceiving approaching and receding sounds. We compared magnetic responses to intensity envelopes of complex sounds to those of white noise sounds, in which intensity change is not perceived as approaching. Sustained magnetic fields over temporal sensors tracked intensity change in complex sounds in an approximately linear fashion, an effect not seen for intensity change in white noise sounds, or for overall intensity. Hence, these fields are likely to track approach/recession, but not the apparent (instantaneous) distance of the sound source, or its intensity as such. As a likely source of this activity, the bilateral inferior temporal gyrus and right temporo-parietal junction emerged. Our results indicate that discrete temporal cortical areas parametrically encode behavioural significance in moving sound sources where the signal unfolded in a manner reminiscent of evidence accumulation. This may help an understanding of how acoustic percepts are evaluated as behaviourally relevant, where our results highlight a crucial role of cortical areas.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Rising sound intensity often signals an approaching sound source and can serve as a powerful warning cue, eliciting phasic attention, perception biases and emotional responses. How the evaluation of approaching sounds unfolds over time remains elusive. Here, we capitalised on the temporal resolution of magnetoencephalograpy (MEG) to investigate in humans a dynamic encoding of perceiving approaching and receding sounds. We compared magnetic responses to intensity envelopes of complex sounds to those of white noise sounds, in which intensity change is not perceived as approaching. Sustained magnetic fields over temporal sensors tracked intensity change in complex sounds in an approximately linear fashion, an effect not seen for intensity change in white noise sounds, or for overall intensity. Hence, these fields are likely to track approach/recession, but not the apparent (instantaneous) distance of the sound source, or its intensity as such. As a likely source of this activity, the bilateral inferior temporal gyrus and right temporo-parietal junction emerged. Our results indicate that discrete temporal cortical areas parametrically encode behavioural significance in moving sound sources where the signal unfolded in a manner reminiscent of evidence accumulation. This may help an understanding of how acoustic percepts are evaluated as behaviourally relevant, where our results highlight a crucial role of cortical areas. |
Mareike Bacha-Trams; Enrico Glerean; Robin Dunbar; Juha M Lahnakoski; Elisa Ryyppö; Mikko Sams; Iiro P Jääskeläinen Differential inter-subject correlation of brain activity when kinship is a variable in moral dilemma Journal Article Scientific Reports, 7 (1), pp. 1–16, 2017. Abstract | Links | BibTeX @article{Bacha-Trams2017,
title = {Differential inter-subject correlation of brain activity when kinship is a variable in moral dilemma},
author = {Mareike Bacha-Trams and Enrico Glerean and Robin Dunbar and Juha M Lahnakoski and Elisa Ryyppö and Mikko Sams and Iiro P Jääskeläinen},
doi = {10.1038/s41598-017-14323-x},
year = {2017},
date = {2017-01-01},
journal = {Scientific Reports},
volume = {7},
number = {1},
pages = {1--16},
abstract = {Previous behavioural studies have shown that humans act more altruistically towards kin. Whether and how knowledge of genetic relatedness translates into differential neurocognitive evaluation of observed social interactions has remained an open question. Here, we investigated how the human brain is engaged when viewing a moral dilemma between genetic vs. non-genetic sisters. During functional magnetic resonance imaging, a movie was shown, depicting refusal of organ donation between two sisters, with subjects guided to believe the sisters were related either genetically or by adoption. Although 90% of the subjects self-reported that genetic relationship was not relevant, their brain activity told a different story. Comparing correlations of brain activity across all subject pairs between the two viewing conditions, we found significantly stronger inter-subject correlations in insula, cingulate, medial and lateral prefrontal, superior temporal, and superior parietal cortices, when the subjects believed that the sisters were genetically related. Cognitive functions previously associated with these areas include moral and emotional conflict regulation, decision making, and mentalizing, suggesting more similar engagement of such functions when observing refusal of altruism from a genetic sister. Our results show that mere knowledge of a genetic relationship between interacting persons robustly modulates social cognition of the perceiver.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Previous behavioural studies have shown that humans act more altruistically towards kin. Whether and how knowledge of genetic relatedness translates into differential neurocognitive evaluation of observed social interactions has remained an open question. Here, we investigated how the human brain is engaged when viewing a moral dilemma between genetic vs. non-genetic sisters. During functional magnetic resonance imaging, a movie was shown, depicting refusal of organ donation between two sisters, with subjects guided to believe the sisters were related either genetically or by adoption. Although 90% of the subjects self-reported that genetic relationship was not relevant, their brain activity told a different story. Comparing correlations of brain activity across all subject pairs between the two viewing conditions, we found significantly stronger inter-subject correlations in insula, cingulate, medial and lateral prefrontal, superior temporal, and superior parietal cortices, when the subjects believed that the sisters were genetically related. Cognitive functions previously associated with these areas include moral and emotional conflict regulation, decision making, and mentalizing, suggesting more similar engagement of such functions when observing refusal of altruism from a genetic sister. Our results show that mere knowledge of a genetic relationship between interacting persons robustly modulates social cognition of the perceiver. |
Daniel Baldauf; Robert Desimone Neural mechanisms of object-based attention Journal Article Science, 344 (6182), pp. 424–427, 2014. Abstract | Links | BibTeX @article{Baldauf2014,
title = {Neural mechanisms of object-based attention},
author = {Daniel Baldauf and Robert Desimone},
url = {http://www.sciencemag.org/cgi/doi/10.1126/science.1247003%0Apapers3://publication/doi/10.1126/science.1247003},
doi = {10.1126/science.1247003},
year = {2014},
date = {2014-01-01},
journal = {Science},
volume = {344},
number = {6182},
pages = {424--427},
abstract = {How we attend to objects and their features that cannot be separated by location is not understood. We presented two temporally and spatially overlapping streams of objects, faces versus houses, and used magnetoencephalography and functional magnetic resonance imaging to separate neuronal responses to attended and unattended objects. Attention to faces versus houses enhanced the sensory responses in the fusiform face area (FFA) and parahippocampal place area (PPA), respectively. The increases in sensory responses were accompanied by induced gamma synchrony between the inferior frontal junction, IFJ, and either FFA or PPA, depending on which object was attended. The IFJ appeared to be the driver of the synchrony, as gamma phases were advanced by 20 ms in IFJ compared to FFA or PPA. Thus, the IFJ may direct the flow of visual processing during object-based attention, at least in part through coupled oscillations with specialized areas such as FFA and PPA. W},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
How we attend to objects and their features that cannot be separated by location is not understood. We presented two temporally and spatially overlapping streams of objects, faces versus houses, and used magnetoencephalography and functional magnetic resonance imaging to separate neuronal responses to attended and unattended objects. Attention to faces versus houses enhanced the sensory responses in the fusiform face area (FFA) and parahippocampal place area (PPA), respectively. The increases in sensory responses were accompanied by induced gamma synchrony between the inferior frontal junction, IFJ, and either FFA or PPA, depending on which object was attended. The IFJ appeared to be the driver of the synchrony, as gamma phases were advanced by 20 ms in IFJ compared to FFA or PPA. Thus, the IFJ may direct the flow of visual processing during object-based attention, at least in part through coupled oscillations with specialized areas such as FFA and PPA. W |
Pinglei Bao; Christopher J Purington; Bosco S Tjan Using an achiasmic human visual system to quantify the relationship between the fMRI BOLD signal and neural response Journal Article eLife, 4 (NOVEMBER2015), pp. 1–21, 2015. Abstract | Links | BibTeX @article{Bao2015a,
title = {Using an achiasmic human visual system to quantify the relationship between the fMRI BOLD signal and neural response},
author = {Pinglei Bao and Christopher J Purington and Bosco S Tjan},
doi = {10.7554/eLife.09600},
year = {2015},
date = {2015-01-01},
journal = {eLife},
volume = {4},
number = {NOVEMBER2015},
pages = {1--21},
abstract = {Achiasma in humans causes gross mis-wiring of the retinal-fugal projection, resulting in overlapped cortical representations of left and right visual hemifields. We show that in areas V1-V3 this overlap is due to two co-located but non-interacting populations of neurons, each with a receptive field serving only one hemifield. Importantly, the two populations share the same local vascular control, resulting in a unique organization useful for quantifying the relationship between neural and fMRI BOLD responses without direct measurement of neural activity. Specifically, we can non-invasively double local neural responses by stimulating both neuronal populations with identical stimuli presented symmetrically across the vertical meridian to both visual hemifields, versus one population by stimulating in one hemifield. Measurements from a series of such doubling experiments show that the amplitude of BOLD response is proportional to approximately 0.5 power of the underlying neural response. Reanalyzing published data shows that this inferred relationship is general.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Achiasma in humans causes gross mis-wiring of the retinal-fugal projection, resulting in overlapped cortical representations of left and right visual hemifields. We show that in areas V1-V3 this overlap is due to two co-located but non-interacting populations of neurons, each with a receptive field serving only one hemifield. Importantly, the two populations share the same local vascular control, resulting in a unique organization useful for quantifying the relationship between neural and fMRI BOLD responses without direct measurement of neural activity. Specifically, we can non-invasively double local neural responses by stimulating both neuronal populations with identical stimuli presented symmetrically across the vertical meridian to both visual hemifields, versus one population by stimulating in one hemifield. Measurements from a series of such doubling experiments show that the amplitude of BOLD response is proportional to approximately 0.5 power of the underlying neural response. Reanalyzing published data shows that this inferred relationship is general. |
D A Barany; V Della-Maggiore; S Viswanathan; M Cieslak; S T Grafton Feature Iinteractions enable decoding of sensorimotor transformations for goal-directed movement Journal Article Journal of Neuroscience, 34 (20), pp. 6860–6873, 2014. Abstract | Links | BibTeX @article{Barany2014,
title = {Feature Iinteractions enable decoding of sensorimotor transformations for goal-directed movement},
author = {D A Barany and V Della-Maggiore and S Viswanathan and M Cieslak and S T Grafton},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.5173-13.2014},
doi = {10.1523/JNEUROSCI.5173-13.2014},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neuroscience},
volume = {34},
number = {20},
pages = {6860--6873},
abstract = {Neurophysiology and neuroimaging evidence shows that the brain represents multiple environmental and body-related features to compute transformations from sensory input to motor output. However, it is unclear how these features interact during goal-directed movement. To investigate this issue, we examined the representations of sensory and motor features of human hand movements within the left-hemisphere motor network. In a rapid event-related fMRI design, we measured cortical activity as participants performed right-handed movements at the wrist, with either of two postures and two amplitudes, to move a cursor to targets at different locations. Using a multivoxel analysis technique with rigorous generalization tests, we reliably distinguished representations of task-related features (primarily target location, movement direction, and posture) in multiple regions. In particular, we identified an interaction between target location and movement direction in the superior parietal lobule, which may underlie a transformation from the location of the target in space to a movement vector. In addition, we found an influence of posture on primary motor, premotor, and parietal regions. Together, these results reveal the complex interactions between different sensory and motor features that drive the computation of sensorimotor transformations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Neurophysiology and neuroimaging evidence shows that the brain represents multiple environmental and body-related features to compute transformations from sensory input to motor output. However, it is unclear how these features interact during goal-directed movement. To investigate this issue, we examined the representations of sensory and motor features of human hand movements within the left-hemisphere motor network. In a rapid event-related fMRI design, we measured cortical activity as participants performed right-handed movements at the wrist, with either of two postures and two amplitudes, to move a cursor to targets at different locations. Using a multivoxel analysis technique with rigorous generalization tests, we reliably distinguished representations of task-related features (primarily target location, movement direction, and posture) in multiple regions. In particular, we identified an interaction between target location and movement direction in the superior parietal lobule, which may underlie a transformation from the location of the target in space to a movement vector. In addition, we found an influence of posture on primary motor, premotor, and parietal regions. Together, these results reveal the complex interactions between different sensory and motor features that drive the computation of sensorimotor transformations. |
Julia Bender; Kyeong Jin Tark; Benedikt Reuter; Norbert Kathmann; Clayton E Curtis Differential roles of the frontal and parietal cortices in the control of saccades Journal Article Brain and Cognition, 83 (1), pp. 1–9, 2013. Abstract | Links | BibTeX @article{Bender2013,
title = {Differential roles of the frontal and parietal cortices in the control of saccades},
author = {Julia Bender and Kyeong Jin Tark and Benedikt Reuter and Norbert Kathmann and Clayton E Curtis},
url = {http://dx.doi.org/10.1016/j.bandc.2013.06.005},
doi = {10.1016/j.bandc.2013.06.005},
year = {2013},
date = {2013-01-01},
journal = {Brain and Cognition},
volume = {83},
number = {1},
pages = {1--9},
publisher = {Elsevier Inc.},
abstract = {Although externally as well as internally-guided eye movements allow us to flexibly explore the visual environment, their differential neural mechanisms remain elusive. A better understanding of these neural mechanisms will help us to understand the control of action and to elucidate the nature of cognitive deficits in certain psychiatric populations (e.g. schizophrenia) that show increased latencies in volitional but not visually-guided saccades. Both the superior precentral sulcus (sPCS) and the intraparietal sulcus (IPS) are implicated in the control of eye movements. However, it remains unknown what differential contributions the two areas make to the programming of visually-guided and internally-guided saccades. In this study we tested the hypotheses that sPCS and IPS distinctly encode internally-guided saccades and visually-guided saccades. We scanned subjects with fMRI while they generated visually-guided and internally-guided delayed saccades. We used multi-voxel pattern analysis to test whether patterns of cue related, preparatory and saccade related activation could be used to predict the direction of the planned eye movement. Results indicate that patterns in the human sPCS predicted internally-guided saccades but not visually-guided saccades in all trial periods and patterns in the IPS predicted internally-guided saccades and visually-guided saccades equally well. The results support the hypothesis that the human sPCS and IPS make distinct contributions to the control of volitional eye movements.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Although externally as well as internally-guided eye movements allow us to flexibly explore the visual environment, their differential neural mechanisms remain elusive. A better understanding of these neural mechanisms will help us to understand the control of action and to elucidate the nature of cognitive deficits in certain psychiatric populations (e.g. schizophrenia) that show increased latencies in volitional but not visually-guided saccades. Both the superior precentral sulcus (sPCS) and the intraparietal sulcus (IPS) are implicated in the control of eye movements. However, it remains unknown what differential contributions the two areas make to the programming of visually-guided and internally-guided saccades. In this study we tested the hypotheses that sPCS and IPS distinctly encode internally-guided saccades and visually-guided saccades. We scanned subjects with fMRI while they generated visually-guided and internally-guided delayed saccades. We used multi-voxel pattern analysis to test whether patterns of cue related, preparatory and saccade related activation could be used to predict the direction of the planned eye movement. Results indicate that patterns in the human sPCS predicted internally-guided saccades but not visually-guided saccades in all trial periods and patterns in the IPS predicted internally-guided saccades and visually-guided saccades equally well. The results support the hypothesis that the human sPCS and IPS make distinct contributions to the control of volitional eye movements. |
Anna K Bonkhoff; Eckart Zimmermann; Gereon R Fink Veridical stimulus localization is linked to human area V5/MT+ activity Journal Article NeuroImage, 156 , pp. 377–387, 2017. Abstract | Links | BibTeX @article{Bonkhoff2017,
title = {Veridical stimulus localization is linked to human area V5/MT+ activity},
author = {Anna K Bonkhoff and Eckart Zimmermann and Gereon R Fink},
doi = {10.1016/j.neuroimage.2017.05.010},
year = {2017},
date = {2017-01-01},
journal = {NeuroImage},
volume = {156},
pages = {377--387},
abstract = {How the brain represents visual space is an unsolved mystery. Spatial localization becomes particularly challenging when visual information processing is briefly disrupted, as in the case of saccadic eye movements, blinks, or visual masks. As we have recently reported, a compression of visual space, illustrated by displacements of shortly flashed stimuli, can be observed in the temporal vicinity of masking stimuli during ocular fixation (Zimmermann et al., 2013). We here aimed at investigating the neural mechanisms underlying these displacements using functional magnetic resonance imaging. On the behavioral level, we detected significant stimulus displacement when visual masks were simultaneously presented. At the neural level, we observed decreased human motion complex V5/MT+ activation associated with these displacements: When comparing trials with a perceived stimulus shift in space to trials of veridical perception of stimulus localization, human V5/MT+ was significantly less activated although no differences in perceived motion can account for this. Data suggest an important role of human V5/MT+ in the process of spatial localization of briefly presented objects and thus extend current concepts of the functions of human V5/MT+.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
How the brain represents visual space is an unsolved mystery. Spatial localization becomes particularly challenging when visual information processing is briefly disrupted, as in the case of saccadic eye movements, blinks, or visual masks. As we have recently reported, a compression of visual space, illustrated by displacements of shortly flashed stimuli, can be observed in the temporal vicinity of masking stimuli during ocular fixation (Zimmermann et al., 2013). We here aimed at investigating the neural mechanisms underlying these displacements using functional magnetic resonance imaging. On the behavioral level, we detected significant stimulus displacement when visual masks were simultaneously presented. At the neural level, we observed decreased human motion complex V5/MT+ activation associated with these displacements: When comparing trials with a perceived stimulus shift in space to trials of veridical perception of stimulus localization, human V5/MT+ was significantly less activated although no differences in perceived motion can account for this. Data suggest an important role of human V5/MT+ in the process of spatial localization of briefly presented objects and thus extend current concepts of the functions of human V5/MT+. |
Rodrigo M Braga; Randy L Buckner Parallel interdigitated distributed networks within the individual estimated by intrinsic functional connectivity Journal Article Neuron, 95 (2), pp. 457–471, 2017. Abstract | Links | BibTeX @article{Braga2017,
title = {Parallel interdigitated distributed networks within the individual estimated by intrinsic functional connectivity},
author = {Rodrigo M Braga and Randy L Buckner},
url = {http://dx.doi.org/10.1016/j.neuron.2017.06.038},
doi = {10.1016/j.neuron.2017.06.038},
year = {2017},
date = {2017-01-01},
journal = {Neuron},
volume = {95},
number = {2},
pages = {457--471},
publisher = {Elsevier Inc.},
abstract = {Certain organizational features of brain networks present in the individual are lost when central tendencies are examined in the group. Here we investigated the detailed network organization of four individuals each scanned 24 times using MRI. We discovered that the distributed network known as the default network is comprised of two separate networks possessing adjacent regions in eight or more cortical zones. A distinction between the networks is that one is coupled to the hippocampal formation while the other is not. Further exploration revealed that these two networks were juxtaposed with additional networks that themselves fractionate group-defined networks. The collective networks display a repeating spatial progression in multiple cortical zones, suggesting that they are embedded within a broad macroscale gradient. Regions contributing to the newly defined networks are spatially variable across individuals and adjacent to distinct networks, raising issues for network estimation in group-averaged data and applied endeavors, including targeted neuromodulation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Certain organizational features of brain networks present in the individual are lost when central tendencies are examined in the group. Here we investigated the detailed network organization of four individuals each scanned 24 times using MRI. We discovered that the distributed network known as the default network is comprised of two separate networks possessing adjacent regions in eight or more cortical zones. A distinction between the networks is that one is coupled to the hippocampal formation while the other is not. Further exploration revealed that these two networks were juxtaposed with additional networks that themselves fractionate group-defined networks. The collective networks display a repeating spatial progression in multiple cortical zones, suggesting that they are embedded within a broad macroscale gradient. Regions contributing to the newly defined networks are spatially variable across individuals and adjacent to distinct networks, raising issues for network estimation in group-averaged data and applied endeavors, including targeted neuromodulation. |
Jan Brascamp; Randolph Blake; Tomas Knapen Negligible fronto-parietal BOLD activity accompanying unreportable switches in bistable perception Journal Article Nature Neuroscience, 18 (11), pp. 1672–1678, 2015. Abstract | Links | BibTeX @article{Brascamp2015,
title = {Negligible fronto-parietal BOLD activity accompanying unreportable switches in bistable perception},
author = {Jan Brascamp and Randolph Blake and Tomas Knapen},
url = {http://dx.doi.org/10.1038/nn.4130},
doi = {10.1038/nn.4130},
year = {2015},
date = {2015-01-01},
journal = {Nature Neuroscience},
volume = {18},
number = {11},
pages = {1672--1678},
publisher = {Nature Publishing Group},
abstract = {The human brain's executive systems have a vital role in deciding and selecting among actions. Selection among alternatives also occurs in the perceptual domain; for instance, when perception switches between interpretations during perceptual bistability. Whether executive systems also underlie this functionality remains debated, with known fronto-parietal concomitants of perceptual switches being variously interpreted as reflecting the switches' cause or as reflecting their consequences. We developed a procedure in which the two eyes receive different inputs and perception demonstrably switches between these inputs, yet the switches themselves are so inconspicuous as to become unreportable, minimizing their executive consequences. Fronto-parietal fMRI BOLD responses that accompanied perceptual switches were similarly minimized in this procedure, indicating that these reflect the switches' consequences rather than their cause. We conclude that perceptual switches do not always rely on executive brain areas and that processes responsible for selection among alternatives may operate outside the brain's executive systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The human brain's executive systems have a vital role in deciding and selecting among actions. Selection among alternatives also occurs in the perceptual domain; for instance, when perception switches between interpretations during perceptual bistability. Whether executive systems also underlie this functionality remains debated, with known fronto-parietal concomitants of perceptual switches being variously interpreted as reflecting the switches' cause or as reflecting their consequences. We developed a procedure in which the two eyes receive different inputs and perception demonstrably switches between these inputs, yet the switches themselves are so inconspicuous as to become unreportable, minimizing their executive consequences. Fronto-parietal fMRI BOLD responses that accompanied perceptual switches were similarly minimized in this procedure, indicating that these reflect the switches' consequences rather than their cause. We conclude that perceptual switches do not always rely on executive brain areas and that processes responsible for selection among alternatives may operate outside the brain's executive systems. |
D J Bridge; J L Voss Hippocampal binding of novel information with dominant memory traces can support both memory stability and change Journal Article Journal of Neuroscience, 34 (6), pp. 2203–2213, 2014. Abstract | Links | BibTeX @article{Bridge2014,
title = {Hippocampal binding of novel information with dominant memory traces can support both memory stability and change},
author = {D J Bridge and J L Voss},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.3819-13.2014},
doi = {10.1523/JNEUROSCI.3819-13.2014},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neuroscience},
volume = {34},
number = {6},
pages = {2203--2213},
abstract = {Memory stability and change are considered opposite outcomes. We tested the counterintuitive notion that both depend on one process: hippocampal binding of memory features to associatively novel information, or associative novelty binding (ANB). Building on the idea that dominant memory features, or “traces,” are most susceptible to modification, we hypothesized that ANB would selectively involve dominant traces. Therefore, memory stability versus change should depend on whether the currently dominant trace is old versus updated; in either case, novel information will be bound with it, causing either maintenance (when old) or change (when updated). People in our experiment studied objects at locations within scenes (contexts). During reactivation in a new context, subjects moved studied objects to new locations either via active location recall or by passively dragging objects to predetermined locations. After active reactivation, the new object location became dominant in memory, whereas after passive reactivation, the old object location maintained dominance. In both cases, hippocampal ANB bound the currently dominant object-location memory with a context with which it was not paired previously (i.e., associatively novel). Stability occurred in the passive condition when ANB united the dominant original location trace with an associatively novel newer context. Change occurred in the active condition when ANB united the dominant updated object location with an associatively novel and older context. Hippocampal ANB of the currently dominant trace with associatively novel contextual information thus provides a single mechanism to support memory stability and change, with shifts in trace dominance during reactivation dictating the outcome.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Memory stability and change are considered opposite outcomes. We tested the counterintuitive notion that both depend on one process: hippocampal binding of memory features to associatively novel information, or associative novelty binding (ANB). Building on the idea that dominant memory features, or “traces,” are most susceptible to modification, we hypothesized that ANB would selectively involve dominant traces. Therefore, memory stability versus change should depend on whether the currently dominant trace is old versus updated; in either case, novel information will be bound with it, causing either maintenance (when old) or change (when updated). People in our experiment studied objects at locations within scenes (contexts). During reactivation in a new context, subjects moved studied objects to new locations either via active location recall or by passively dragging objects to predetermined locations. After active reactivation, the new object location became dominant in memory, whereas after passive reactivation, the old object location maintained dominance. In both cases, hippocampal ANB bound the currently dominant object-location memory with a context with which it was not paired previously (i.e., associatively novel). Stability occurred in the passive condition when ANB united the dominant original location trace with an associatively novel newer context. Change occurred in the active condition when ANB united the dominant updated object location with an associatively novel and older context. Hippocampal ANB of the currently dominant trace with associatively novel contextual information thus provides a single mechanism to support memory stability and change, with shifts in trace dominance during reactivation dictating the outcome. |
Donna J Bridge; Neal J Cohen; Joel L Voss Distinct hippocampal versus frontoparietal network contributions to retrieval and memory-guided exploration Journal Article Journal of Cognitive Neuroscience, 29 (8), pp. 1324–1338, 2017. Abstract | Links | BibTeX @article{Bridge2017,
title = {Distinct hippocampal versus frontoparietal network contributions to retrieval and memory-guided exploration},
author = {Donna J Bridge and Neal J Cohen and Joel L Voss},
url = {https://www-mitpressjournals-org.myaccess.library.utoronto.ca/doi/pdf/10.1162/jocn_a_01143},
doi = {10.1162/jocn_a_01143},
year = {2017},
date = {2017-01-01},
journal = {Journal of Cognitive Neuroscience},
volume = {29},
number = {8},
pages = {1324--1338},
abstract = {Memory can profoundly influence new learning, presumably because memory optimizes exploration of to-be-learned material. Although hippocampus and frontoparietal networks have been implicated in memory-guided exploration, their specific and interactive roles have not been identified. We examined eye movements during fMRI scanning to identify neural correlates of the influences of memory retrieval on exploration and learning. After retrieval of one object in a multiobject array, viewing was strategically directed away from the retrieved object toward nonretrieved objects, such that exploration was directed toward to-be-learned content. Retrieved objects later served as optimal reminder cues, indicating that exploration caused memory to become structured around the retrieved content. Hippocampal activity was associated with memory retrieval, whereas frontoparietal activity varied with strategic viewing patterns deployed after retrieval, thus providing spatiotemporal dissociation of memory retrieval from memory-guided learning strategies. Time-lagged fMRI connectivity analyses indicated that hippocampal activity predicted frontoparietal activity to a greater extent for a condition in which retrieval guided exploration occurred than for a passive control condition in which exploration was not influenced by retrieval. This demonstrates network-level interaction effects specific to influences of memory on strategic exploration. These findings show how memory guides behavior during learning and demonstrate distinct yet interactive hippocampal-frontoparietal roles in implementing strategic exploration behaviors that determine the fate of evolving memory representations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Memory can profoundly influence new learning, presumably because memory optimizes exploration of to-be-learned material. Although hippocampus and frontoparietal networks have been implicated in memory-guided exploration, their specific and interactive roles have not been identified. We examined eye movements during fMRI scanning to identify neural correlates of the influences of memory retrieval on exploration and learning. After retrieval of one object in a multiobject array, viewing was strategically directed away from the retrieved object toward nonretrieved objects, such that exploration was directed toward to-be-learned content. Retrieved objects later served as optimal reminder cues, indicating that exploration caused memory to become structured around the retrieved content. Hippocampal activity was associated with memory retrieval, whereas frontoparietal activity varied with strategic viewing patterns deployed after retrieval, thus providing spatiotemporal dissociation of memory retrieval from memory-guided learning strategies. Time-lagged fMRI connectivity analyses indicated that hippocampal activity predicted frontoparietal activity to a greater extent for a condition in which retrieval guided exploration occurred than for a passive control condition in which exploration was not influenced by retrieval. This demonstrates network-level interaction effects specific to influences of memory on strategic exploration. These findings show how memory guides behavior during learning and demonstrate distinct yet interactive hippocampal-frontoparietal roles in implementing strategic exploration behaviors that determine the fate of evolving memory representations. |
Ruud L van den Brink; Thomas Pfeffer; Christopher M Warren; Peter R Murphy; Klodiana-Daphne Tona; Nic J A van der Wee; Eric Giltay; Martijn S van Noorden; Serge A R B Rombouts; Tobias H Donner; Sander Nieuwenhuis Catecholaminergic neuromodulation shapes intrinsic MRI functional connectivity in the human brain Journal Article Journal of Neuroscience, 36 (30), pp. 7865–7876, 2016. Abstract | Links | BibTeX @article{Brink2016b,
title = {Catecholaminergic neuromodulation shapes intrinsic MRI functional connectivity in the human brain},
author = {Ruud L van den Brink and Thomas Pfeffer and Christopher M Warren and Peter R Murphy and Klodiana-Daphne Tona and Nic J A van der Wee and Eric Giltay and Martijn S van Noorden and Serge A R B Rombouts and Tobias H Donner and Sander Nieuwenhuis},
url = {http://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.0744-16.2016},
doi = {10.1523/JNEUROSCI.0744-16.2016},
year = {2016},
date = {2016-01-01},
journal = {Journal of Neuroscience},
volume = {36},
number = {30},
pages = {7865--7876},
abstract = {The brain commonly exhibits spontaneous (i.e., in the absence of a task) fluctuations in neural activity that are correlated across brain regions. It has been established that the spatial structure, or topography, of these intrinsic correlations is in part determined by the fixed anatomical connectivity between regions. However, it remains unclear which factors dynamically sculpt this topography as a function of brain state. Potential candidate factors are subcortical catecholaminergic neuromodulatory systems, such as the locus ceruleus-norepinephrine system, which send diffuse projections to most parts of the forebrain. Here, we systematically characterized the effects of endogenous central neuromodulation on correlated fluctuations during rest in the human brain. Using a double-blind placebo-controlled crossover design, we pharmacologically increased synaptic catecholamine levels by administering atomoxetine, an NE transporter blocker, and examined the effects on the strength and spatial structure of resting-state MRI functional connectivity. First, atomoxetine reduced the strength of inter-regional correlations across three levels of spatial organization, indicating that catecholamines reduce the strength of functional interactions during rest. Second, this modulatory effectonintrinsic correlations exhibited a substantial degree of spatial specificity: the decrease in functional connectivity showed an anterior–posterior gradient in the cortex, depended on the strength of baseline functional connectivity, and was strongest for connections between regions belonging to distinct resting-state networks. Thus, catecholamines reduce intrinsic correlations in a spatially heterogeneous fashion. We conclude that neuromodulation is an important factor shaping the topography of intrinsic functional connectivity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The brain commonly exhibits spontaneous (i.e., in the absence of a task) fluctuations in neural activity that are correlated across brain regions. It has been established that the spatial structure, or topography, of these intrinsic correlations is in part determined by the fixed anatomical connectivity between regions. However, it remains unclear which factors dynamically sculpt this topography as a function of brain state. Potential candidate factors are subcortical catecholaminergic neuromodulatory systems, such as the locus ceruleus-norepinephrine system, which send diffuse projections to most parts of the forebrain. Here, we systematically characterized the effects of endogenous central neuromodulation on correlated fluctuations during rest in the human brain. Using a double-blind placebo-controlled crossover design, we pharmacologically increased synaptic catecholamine levels by administering atomoxetine, an NE transporter blocker, and examined the effects on the strength and spatial structure of resting-state MRI functional connectivity. First, atomoxetine reduced the strength of inter-regional correlations across three levels of spatial organization, indicating that catecholamines reduce the strength of functional interactions during rest. Second, this modulatory effectonintrinsic correlations exhibited a substantial degree of spatial specificity: the decrease in functional connectivity showed an anterior–posterior gradient in the cortex, depended on the strength of baseline functional connectivity, and was strongest for connections between regions belonging to distinct resting-state networks. Thus, catecholamines reduce intrinsic correlations in a spatially heterogeneous fashion. We conclude that neuromodulation is an important factor shaping the topography of intrinsic functional connectivity. |
James A Brissenden; Emily J Levin; David E Osher; Mark A Halko; David C Somers Functional evidence for a cerebellar node of the dorsal attention network Journal Article Journal of Neuroscience, 36 (22), pp. 6083–6096, 2016. Abstract | Links | BibTeX @article{Brissenden2016,
title = {Functional evidence for a cerebellar node of the dorsal attention network},
author = {James A Brissenden and Emily J Levin and David E Osher and Mark A Halko and David C Somers},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.0344-16.2016},
doi = {10.1523/JNEUROSCI.0344-16.2016},
year = {2016},
date = {2016-01-01},
journal = {Journal of Neuroscience},
volume = {36},
number = {22},
pages = {6083--6096},
abstract = {The "dorsal attention network" or "frontoparietal network" refers to a network of cortical regions that support sustained attention and working memory. Recent work has demonstrated that cortical nodes of the dorsal attention network possess intrinsic functional connections with a region in ventral cerebellum, in the vicinity of lobules VII/VIII. Here, we performed a series of task-based and resting-state fMRI experiments to investigate cerebellar participation in the dorsal attention network in humans. We observed that visual working memory and visual attention tasks robustly recruit cerebellar lobules VIIb and VIIIa, in addition to canonical cortical dorsal attention network regions. Across the cerebellum, resting-state functional connectivity with the cortical dorsal attention network strongly predicted the level of activation produced by attention and working memory tasks. Critically, cerebellar voxels that were most strongly connected with the dorsal attention network selectively exhibited load-dependent activity, a hallmark of the neural structures that support visual working memory. Finally, we examined intrinsic functional connectivity between task-responsive portions of cerebellar lobules VIIb/VIIIa and cortex. Cerebellum-to-cortex functional connectivity strongly predicted the pattern of cortical activation during task performance. Moreover, resting-state connectivity patterns revealed that cerebellar lobules VIIb/VIIIa group with cortical nodes of the dorsal attention network. This evidence leads us to conclude that the conceptualization of the dorsal attention network should be expanded to include cerebellar lobules VIIb/VIIIa.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The "dorsal attention network" or "frontoparietal network" refers to a network of cortical regions that support sustained attention and working memory. Recent work has demonstrated that cortical nodes of the dorsal attention network possess intrinsic functional connections with a region in ventral cerebellum, in the vicinity of lobules VII/VIII. Here, we performed a series of task-based and resting-state fMRI experiments to investigate cerebellar participation in the dorsal attention network in humans. We observed that visual working memory and visual attention tasks robustly recruit cerebellar lobules VIIb and VIIIa, in addition to canonical cortical dorsal attention network regions. Across the cerebellum, resting-state functional connectivity with the cortical dorsal attention network strongly predicted the level of activation produced by attention and working memory tasks. Critically, cerebellar voxels that were most strongly connected with the dorsal attention network selectively exhibited load-dependent activity, a hallmark of the neural structures that support visual working memory. Finally, we examined intrinsic functional connectivity between task-responsive portions of cerebellar lobules VIIb/VIIIa and cortex. Cerebellum-to-cortex functional connectivity strongly predicted the pattern of cortical activation during task performance. Moreover, resting-state connectivity patterns revealed that cerebellar lobules VIIb/VIIIa group with cortical nodes of the dorsal attention network. This evidence leads us to conclude that the conceptualization of the dorsal attention network should be expanded to include cerebellar lobules VIIb/VIIIa. |
Anouk J de Brouwer; Jeroen B J Smeets; Tjerk P Gutteling; I Toni; Pieter W Medendorp The Müller-Lyer illusion affects visuomotor updating in the dorsal visual stream Journal Article Neuropsychologia, 77 , pp. 119–127, 2015. Abstract | Links | BibTeX @article{Brouwer2015,
title = {The Müller-Lyer illusion affects visuomotor updating in the dorsal visual stream},
author = {Anouk J de Brouwer and Jeroen B J Smeets and Tjerk P Gutteling and I Toni and Pieter W Medendorp},
url = {http://dx.doi.org/10.1016/j.neuropsychologia.2015.08.012},
doi = {10.1016/j.neuropsychologia.2015.08.012},
year = {2015},
date = {2015-01-01},
journal = {Neuropsychologia},
volume = {77},
pages = {119--127},
publisher = {Elsevier},
abstract = {To guide our actions, the brain has developed mechanisms to code target locations in egocentric coordinates (i.e., with respect to the observer), and to update these when the observer moves. The latter mechanism, called visuomotor updating, is implemented in the dorsal visual stream of the brain. In contrast, the ventral visual stream is assumed to transform target locations into an allocentric reference frame that is highly sensitive to visual contextual illusions. Here, we tested the effect of the Müller-Lyer illusion on visuomotor updating in a double-step saccade task. Using the same paradigm in a 3T fMRI scanner, we investigated the effect of the illusion on the neural correlate of the updating process. Participants briefly viewed the Brentano version of the Müller-Lyer illusion with a target at its middle vertex, while fixating at one of the two endpoints of the illusion. Shortly after the disappearance of the stimulus, the eyes' fixation point moved to a position outside the illusion. After a delay, participants made a saccade to the remembered position of the target. The landing position of this saccade was systematically displaced in a manner congruent with the perceptual illusion, showing that visuomotor updating is affected by the illusion. fMRI results showed that the BOLD response in the occipito-parietal cortex (area V7) and the intraparietal sulcus related to planning of the saccade to the updated target was also modulated by the configuration of the illusion. This suggests that the dorsal visual stream represents perceived rather than physical locations of remembered saccade targets.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
To guide our actions, the brain has developed mechanisms to code target locations in egocentric coordinates (i.e., with respect to the observer), and to update these when the observer moves. The latter mechanism, called visuomotor updating, is implemented in the dorsal visual stream of the brain. In contrast, the ventral visual stream is assumed to transform target locations into an allocentric reference frame that is highly sensitive to visual contextual illusions. Here, we tested the effect of the Müller-Lyer illusion on visuomotor updating in a double-step saccade task. Using the same paradigm in a 3T fMRI scanner, we investigated the effect of the illusion on the neural correlate of the updating process. Participants briefly viewed the Brentano version of the Müller-Lyer illusion with a target at its middle vertex, while fixating at one of the two endpoints of the illusion. Shortly after the disappearance of the stimulus, the eyes' fixation point moved to a position outside the illusion. After a delay, participants made a saccade to the remembered position of the target. The landing position of this saccade was systematically displaced in a manner congruent with the perceptual illusion, showing that visuomotor updating is affected by the illusion. fMRI results showed that the BOLD response in the occipito-parietal cortex (area V7) and the intraparietal sulcus related to planning of the saccade to the updated target was also modulated by the configuration of the illusion. This suggests that the dorsal visual stream represents perceived rather than physical locations of remembered saccade targets. |
Harriet R Brown; Karl J Friston The functional anatomy of attention: A DCM study Journal Article Frontiers in Human Neuroscience, 7 (December), 2013. Abstract | Links | BibTeX @article{Brown2013,
title = {The functional anatomy of attention: A DCM study},
author = {Harriet R Brown and Karl J Friston},
url = {http://journal.frontiersin.org/article/10.3389/fnhum.2013.00784/abstract},
doi = {10.3389/fnhum.2013.00784},
year = {2013},
date = {2013-01-01},
journal = {Frontiers in Human Neuroscience},
volume = {7},
number = {December},
abstract = {Recent formulations of attention—in terms of predictive coding—associate attentional gain with the expected precision of sensory information. Formal models of the Posner paradigm suggest that validity effects can be explained in a principled (Bayes optimal) fashion in terms of a cue-dependent setting of precision or gain on the sensory channels reporting anticipated target locations, which is updated selectively by invalid targets. This normative model is equipped with a biologically plausible process theory in the form of predictive coding, where precision is encoded by the gain of superficial pyramidal cells reporting prediction error. We used dynamic causal modeling to assess the evidence in magnetoencephalographic responses for cue-dependent and top-down updating of superficial pyramidal cell gain. Bayesian model comparison suggested that it is almost certain that differences in superficial pyramidal cells gain—and its top-down modulation—contribute to observed responses; and we could be more than 80% certain that anticipatory effects on post-synaptic gain are limited to visual (extrastriate) sources. These empirical results speak to the role of attention in optimizing perceptual inference and its formulation in terms of predictive coding.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Recent formulations of attention—in terms of predictive coding—associate attentional gain with the expected precision of sensory information. Formal models of the Posner paradigm suggest that validity effects can be explained in a principled (Bayes optimal) fashion in terms of a cue-dependent setting of precision or gain on the sensory channels reporting anticipated target locations, which is updated selectively by invalid targets. This normative model is equipped with a biologically plausible process theory in the form of predictive coding, where precision is encoded by the gain of superficial pyramidal cells reporting prediction error. We used dynamic causal modeling to assess the evidence in magnetoencephalographic responses for cue-dependent and top-down updating of superficial pyramidal cell gain. Bayesian model comparison suggested that it is almost certain that differences in superficial pyramidal cells gain—and its top-down modulation—contribute to observed responses; and we could be more than 80% certain that anticipatory effects on post-synaptic gain are limited to visual (extrastriate) sources. These empirical results speak to the role of attention in optimizing perceptual inference and its formulation in terms of predictive coding. |
Korhan Buyukturkoglu; Hans Roettgers; Jens Sommer; Mohit Rana; Leonie Dietzsch; Ezgi Belkis Arikan; Ralf Veit; Rahim Malekshahi; Tilo Kircher; Niels Birbaumer; Ranganatha Sitaram; Sergio Ruiz Self-regulation of anterior insula using real-time fMRI and its behavioral effects in obsessive compulsive disorder: A feasibility study Journal Article PLoS ONE, 10 (8), pp. 1–26, 2015. Abstract | Links | BibTeX @article{Buyukturkoglu2015,
title = {Self-regulation of anterior insula using real-time fMRI and its behavioral effects in obsessive compulsive disorder: A feasibility study},
author = {Korhan Buyukturkoglu and Hans Roettgers and Jens Sommer and Mohit Rana and Leonie Dietzsch and Ezgi Belkis Arikan and Ralf Veit and Rahim Malekshahi and Tilo Kircher and Niels Birbaumer and Ranganatha Sitaram and Sergio Ruiz},
doi = {10.1371/journal.pone.0135872},
year = {2015},
date = {2015-01-01},
journal = {PLoS ONE},
volume = {10},
number = {8},
pages = {1--26},
abstract = {Introduction: Obsessive-compulsive disorder (OCD) is a common and chronic condition that can have disabling effects throughout the patient's lifespan. Frequent symptoms among OCD patients include fear of contamination and washing compulsions. Several studies have shown a link between contamination fears, disgust over-reactivity, and insula activation in OCD. In concordance with the role of insula in disgust processing, new neural models based on neuroimaging studies suggest that abnormally high activations of insula could be implicated in OCD psychopathology, at least in the subgroup of patients with contamination fears and washing compulsions. Methods: In the current study, we used a Brain Computer Interface (BCI) based on real-time func- tional magnetic resonance imaging (rtfMRI) to aid OCD patients to achieve down-regula- tion of the Blood Oxygenation Level Dependent (BOLD) signal in anterior insula. Our first aim was to investigate whether patients with contamination obsessions and washing com- pulsions can learn to volitionally decrease (down-regulate) activity in the insula in the pres- ence of disgust/anxiety provoking stimuli. Our second aimwas to evaluate the effect of down-regulation on clinical, behavioural and physiological changes pertaining to OCD symptoms. Hence, several pre- and post-training measures were performed, i.e., con- fronting the patient with a disgust/anxiety inducing real-world object (Ecological Disgust Test), and subjective rating and physiological responses (heart rate, skin conductance level) of disgust towards provoking pictures. Results: Results of this pilot study, performed in 3 patients (2 females), show that OCD patients can gain self-control of the BOLD activity of insula, albeit to different degrees. In two patients positive changes in behaviour in the EDT were observed following the rtfMRI trainings. Behavioural changes were also confirmed by reductions in the negative valence and in the subjective perception of disgust towards symptom provoking images. Conclusion: Although preliminary, results of this study confirmed that insula down-regulation is possible in patients suffering from OCD, and that volitional decreases of insula activation could be used for symptom alleviation in this disorder.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Introduction: Obsessive-compulsive disorder (OCD) is a common and chronic condition that can have disabling effects throughout the patient's lifespan. Frequent symptoms among OCD patients include fear of contamination and washing compulsions. Several studies have shown a link between contamination fears, disgust over-reactivity, and insula activation in OCD. In concordance with the role of insula in disgust processing, new neural models based on neuroimaging studies suggest that abnormally high activations of insula could be implicated in OCD psychopathology, at least in the subgroup of patients with contamination fears and washing compulsions. Methods: In the current study, we used a Brain Computer Interface (BCI) based on real-time func- tional magnetic resonance imaging (rtfMRI) to aid OCD patients to achieve down-regula- tion of the Blood Oxygenation Level Dependent (BOLD) signal in anterior insula. Our first aim was to investigate whether patients with contamination obsessions and washing com- pulsions can learn to volitionally decrease (down-regulate) activity in the insula in the pres- ence of disgust/anxiety provoking stimuli. Our second aimwas to evaluate the effect of down-regulation on clinical, behavioural and physiological changes pertaining to OCD symptoms. Hence, several pre- and post-training measures were performed, i.e., con- fronting the patient with a disgust/anxiety inducing real-world object (Ecological Disgust Test), and subjective rating and physiological responses (heart rate, skin conductance level) of disgust towards provoking pictures. Results: Results of this pilot study, performed in 3 patients (2 females), show that OCD patients can gain self-control of the BOLD activity of insula, albeit to different degrees. In two patients positive changes in behaviour in the EDT were observed following the rtfMRI trainings. Behavioural changes were also confirmed by reductions in the negative valence and in the subjective perception of disgust towards symptom provoking images. Conclusion: Although preliminary, results of this study confirmed that insula down-regulation is possible in patients suffering from OCD, and that volitional decreases of insula activation could be used for symptom alleviation in this disorder. |
Laura Cacciamani; Erica Wager; Mary A Peterson; Paige E Scalf Age-related changes in perirhinal cortex sensitivity to configuration and part familiarity and connectivity to visual cortex Journal Article Frontiers in Aging Neuroscience, 9 , pp. 1–15, 2017. Abstract | Links | BibTeX @article{Cacciamani2017,
title = {Age-related changes in perirhinal cortex sensitivity to configuration and part familiarity and connectivity to visual cortex},
author = {Laura Cacciamani and Erica Wager and Mary A Peterson and Paige E Scalf},
doi = {10.3389/fnagi.2017.00291},
year = {2017},
date = {2017-01-01},
journal = {Frontiers in Aging Neuroscience},
volume = {9},
pages = {1--15},
abstract = {The perirhinal cortex (PRC) is a medial temporal lobe (MTL) structure known to be involved in assessing whether an object is familiar (i.e., meaningful) or novel. Recent evidence shows that the PRC is sensitive to the familiarity of both whole object configurations and their parts, and suggests the PRC may modulate part familiarity responses in V2. Here, using functional magnetic resonance imaging (fMRI), we investigated age-related decline in the PRC's sensitivity to part/configuration familiarity and assessed its functional connectivity to visual cortex in young and older adults. Participants categorized peripherally presented silhouettes as familiar ("real-world") or novel. Part/configuration familiarity was manipulated via three silhouette configurations: Familiar (parts/configurations familiar), Control Novel (parts/configurations novel), and Part-Rearranged Novel (parts familiar, configurations novel). "Real-world" judgments were less accurate than "novel" judgments, although accuracy did not differ between age groups. The fMRI data revealed differential neural activity, however: In young adults, a linear pattern of activation was observed in left hemisphere (LH) PRC, with Familiar textgreater Control Novel textgreater Part-Rearranged Novel. Older adults did not show this pattern, indicating age-related decline in the PRC's sensitivity to part/configuration familiarity. A functional connectivity analysis revealed a significant coupling between the PRC and V2 in the LH in young adults only. Older adults showed a linear pattern of activation in the temporopolar cortex (TPC), but no evidence of TPC-V2 connectivity. This is the first study to demonstrate age-related decline in the PRC's representations of part/configuration familiarity and its covariance with visual cortex.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The perirhinal cortex (PRC) is a medial temporal lobe (MTL) structure known to be involved in assessing whether an object is familiar (i.e., meaningful) or novel. Recent evidence shows that the PRC is sensitive to the familiarity of both whole object configurations and their parts, and suggests the PRC may modulate part familiarity responses in V2. Here, using functional magnetic resonance imaging (fMRI), we investigated age-related decline in the PRC's sensitivity to part/configuration familiarity and assessed its functional connectivity to visual cortex in young and older adults. Participants categorized peripherally presented silhouettes as familiar ("real-world") or novel. Part/configuration familiarity was manipulated via three silhouette configurations: Familiar (parts/configurations familiar), Control Novel (parts/configurations novel), and Part-Rearranged Novel (parts familiar, configurations novel). "Real-world" judgments were less accurate than "novel" judgments, although accuracy did not differ between age groups. The fMRI data revealed differential neural activity, however: In young adults, a linear pattern of activation was observed in left hemisphere (LH) PRC, with Familiar textgreater Control Novel textgreater Part-Rearranged Novel. Older adults did not show this pattern, indicating age-related decline in the PRC's sensitivity to part/configuration familiarity. A functional connectivity analysis revealed a significant coupling between the PRC and V2 in the LH in young adults only. Older adults showed a linear pattern of activation in the temporopolar cortex (TPC), but no evidence of TPC-V2 connectivity. This is the first study to demonstrate age-related decline in the PRC's representations of part/configuration familiarity and its covariance with visual cortex. |
Florence Campana; Ignacio Rebollo; Anne Urai; Valentin Wyart; Catherine Tallon-Baudry Conscious vision proceeds from global to local content in goal-directed tasks and spontaneous vision Journal Article Journal of Neuroscience, 36 (19), pp. 5200–5213, 2016. Abstract | Links | BibTeX @article{Campana2016,
title = {Conscious vision proceeds from global to local content in goal-directed tasks and spontaneous vision},
author = {Florence Campana and Ignacio Rebollo and Anne Urai and Valentin Wyart and Catherine Tallon-Baudry},
url = {http://www.jneurosci.org/lookup/doi/10.1523/JNEUROSCI.3619-15.2016},
doi = {10.1523/JNEUROSCI.3619-15.2016},
year = {2016},
date = {2016-01-01},
journal = {Journal of Neuroscience},
volume = {36},
number = {19},
pages = {5200--5213},
abstract = {The reverse hierarchy theory (Hochstein and Ahissar, 2002) makes strong, but so far untested, predictions on conscious vision. In this theory, local details encoded in lower-order visual areas are unconsciously processed before being automatically and rapidly combined into global information in higher-order visual areas, where conscious percepts emerge. Contingent on current goals, local details can afterward be consciously retrieved. This model therefore predicts that (1) global information is perceived faster than local details, (2) global information is computed regardless of task demands during early visual processing, and (3) spontaneous vision is dominated by global percepts. We designed novel textured stimuli that are, as opposed to the classic Navon's letters, truly hierarchical (i.e., where global information is solely defined by local information but where local and global orientations can still be manipulated separately). In line with the predictions, observers were systematically faster reporting global than local properties of those stimuli. Second, global information could be decoded from magneto-encephalographic data during early visual processing regardless of task demands. Last, spontaneous subjective reports were dominated by global information and the frequency and speed of spontaneous global perception correlated with the accuracy and speed in the global task. No such correlation was observed for local information. We therefore show that information at different levels of the visual hierarchy is not equally likely to become conscious; rather, conscious percepts emerge preferentially at a global level. We further show that spontaneous reports can be reliable and are tightly linked to objective performance at the global level.},
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The reverse hierarchy theory (Hochstein and Ahissar, 2002) makes strong, but so far untested, predictions on conscious vision. In this theory, local details encoded in lower-order visual areas are unconsciously processed before being automatically and rapidly combined into global information in higher-order visual areas, where conscious percepts emerge. Contingent on current goals, local details can afterward be consciously retrieved. This model therefore predicts that (1) global information is perceived faster than local details, (2) global information is computed regardless of task demands during early visual processing, and (3) spontaneous vision is dominated by global percepts. We designed novel textured stimuli that are, as opposed to the classic Navon's letters, truly hierarchical (i.e., where global information is solely defined by local information but where local and global orientations can still be manipulated separately). In line with the predictions, observers were systematically faster reporting global than local properties of those stimuli. Second, global information could be decoded from magneto-encephalographic data during early visual processing regardless of task demands. Last, spontaneous subjective reports were dominated by global information and the frequency and speed of spontaneous global perception correlated with the accuracy and speed in the global task. No such correlation was observed for local information. We therefore show that information at different levels of the visual hierarchy is not equally likely to become conscious; rather, conscious percepts emerge preferentially at a global level. We further show that spontaneous reports can be reliable and are tightly linked to objective performance at the global level. |
Almudena Capilla; Pascal Belin; Joachim Gross The early spatio-temporal correlates and task independence of cerebral voice processing studied with MEG Journal Article Cerebral Cortex, 23 (6), pp. 1388–1395, 2013. Abstract | Links | BibTeX @article{Capilla2013,
title = {The early spatio-temporal correlates and task independence of cerebral voice processing studied with MEG},
author = {Almudena Capilla and Pascal Belin and Joachim Gross},
doi = {10.1093/cercor/bhs119},
year = {2013},
date = {2013-01-01},
journal = {Cerebral Cortex},
volume = {23},
number = {6},
pages = {1388--1395},
abstract = {Functional magnetic resonance imaging studies have repeatedly provided evidence for temporal voice areas (TVAs) with particular sensitivity to human voices along bilateral mid/anterior superior temporal sulci and superior temporal gyri (STS/STG). In contrast, electrophysiological studies of the spatio-temporal correlates of cerebral voice processing have yielded contradictory results, finding the earliest correlates either at ∼300-400 ms, or earlier at ∼200 ms ("fronto-temporal positivity to voice", FTPV). These contradictory results are likely the consequence of different stimulus sets and attentional demands. Here, we recorded magnetoencephalography activity while participants listened to diverse types of vocal and non-vocal sounds and performed different tasks varying in attentional demands. Our results confirm the existence of an early voice-preferential magnetic response (FTPVm, the magnetic counterpart of the FTPV) peaking at about 220 ms and distinguishing between vocal and non-vocal sounds as early as 150 ms after stimulus onset. The sources underlying the FTPVm were localized along bilateral mid-STS/STG, largely overlapping with the TVAs. The FTPVm was consistently observed across different stimulus subcategories, including speech and non-speech vocal sounds, and across different tasks. These results demonstrate the early, largely automatic recruitment of focal, voice-selective cerebral mechanisms with a time-course comparable to that of face processing.},
keywords = {},
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Functional magnetic resonance imaging studies have repeatedly provided evidence for temporal voice areas (TVAs) with particular sensitivity to human voices along bilateral mid/anterior superior temporal sulci and superior temporal gyri (STS/STG). In contrast, electrophysiological studies of the spatio-temporal correlates of cerebral voice processing have yielded contradictory results, finding the earliest correlates either at ∼300-400 ms, or earlier at ∼200 ms ("fronto-temporal positivity to voice", FTPV). These contradictory results are likely the consequence of different stimulus sets and attentional demands. Here, we recorded magnetoencephalography activity while participants listened to diverse types of vocal and non-vocal sounds and performed different tasks varying in attentional demands. Our results confirm the existence of an early voice-preferential magnetic response (FTPVm, the magnetic counterpart of the FTPV) peaking at about 220 ms and distinguishing between vocal and non-vocal sounds as early as 150 ms after stimulus onset. The sources underlying the FTPVm were localized along bilateral mid-STS/STG, largely overlapping with the TVAs. The FTPVm was consistently observed across different stimulus subcategories, including speech and non-speech vocal sounds, and across different tasks. These results demonstrate the early, largely automatic recruitment of focal, voice-selective cerebral mechanisms with a time-course comparable to that of face processing. |
Daniel Carey; Francesco Caprini; Micah Allen; Antoine Lutti; Nikolaus Weiskopf; Geraint Rees; Martina F Callaghan; Frederic Dick Quantitative MRI provides markers of intra-, inter-regional, and age-related differences in young adult cortical microstructure Journal Article NeuroImage, 182 , pp. 429–440, 2018. Abstract | Links | BibTeX @article{Carey2018,
title = {Quantitative MRI provides markers of intra-, inter-regional, and age-related differences in young adult cortical microstructure},
author = {Daniel Carey and Francesco Caprini and Micah Allen and Antoine Lutti and Nikolaus Weiskopf and Geraint Rees and Martina F Callaghan and Frederic Dick},
url = {https://doi.org/10.1016/j.neuroimage.2017.11.066},
doi = {10.1016/j.neuroimage.2017.11.066},
year = {2018},
date = {2018-01-01},
journal = {NeuroImage},
volume = {182},
pages = {429--440},
publisher = {Elsevier Ltd},
abstract = {Measuring the structural composition of the cortex is critical to understanding typical development, yet few investigations in humans have charted markers in vivo that are sensitive to tissue microstructural attributes. Here, we used a well-validated quantitative MR protocol to measure four parameters (R1, MT, R2* PD*) that differ in their sensitivity to facets of the tissue microstructural environment (R1, MT: myelin, macromolecular content; R2*: myelin, paramagnetic ions, i.e., iron; PD*: free water content). Mapping these parameters across cortical regions in a young adult cohort (18–39 years},
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tppubtype = {article}
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Measuring the structural composition of the cortex is critical to understanding typical development, yet few investigations in humans have charted markers in vivo that are sensitive to tissue microstructural attributes. Here, we used a well-validated quantitative MR protocol to measure four parameters (R1, MT, R2* PD*) that differ in their sensitivity to facets of the tissue microstructural environment (R1, MT: myelin, macromolecular content; R2*: myelin, paramagnetic ions, i.e., iron; PD*: free water content). Mapping these parameters across cortical regions in a young adult cohort (18–39 years |
Nathan Caruana; Jon Brock; Alexandra Woolgar A frontotemporoparietal network common to initiating and responding to joint attention bids Journal Article NeuroImage, 108 , pp. 34–46, 2015. Abstract | Links | BibTeX @article{Caruana2015,
title = {A frontotemporoparietal network common to initiating and responding to joint attention bids},
author = {Nathan Caruana and Jon Brock and Alexandra Woolgar},
url = {http://dx.doi.org/10.1016/j.neuroimage.2014.12.041},
doi = {10.1016/j.neuroimage.2014.12.041},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage},
volume = {108},
pages = {34--46},
publisher = {Elsevier B.V.},
abstract = {Joint attention is a fundamental cognitive ability that supports daily interpersonal relationships and communication. The Parallel Distributed Processing model (PDPM) postulates that responding to (RJA) and initiating (IJA) joint attention are predominantly supported by posterior-parietal and frontal regions respectively. It also argues that these neural networks integrate during development, supporting the parallel processes of self- and other-attention representation during interactions. However, direct evidence for the PDPM is limited due to a lack of ecologically valid experimental paradigms that can capture both RJA and IJA. Building on existing interactive approaches, we developed a virtual reality paradigm where participants engaged in an online interaction to complete a cooperative task. By including tightly controlled baseline conditions to remove activity associated with non-social task demands, we were able to directly contrast the neural correlates of RJA and IJA to determine whether these processes are supported by common brain regions. Both RJA and IJA activated broad frontotemporoparietal networks. Critically, a conjunction analysis identified that a subset of these regions were common to both RJA and IJA. This right-lateralised network included the dorsal portion of the middle frontal gyrus (MFG), inferior frontal gyrus (IFG), middle temporal gyrus (MTG), precentral gyrus, posterior superior temporal sulcus (pSTS), temporoparietal junction (TPJ) and precuneus. Additional activation was observed in this network for IJA relative to RJA at MFG, IFG, TPJ and precuneus. This is the first imaging study to directly investigate the neural correlates common to RJA and IJA engagement, and thus support the assumption that a broad integrated network underlies the parallel aspects of both initiating and responding to joint attention.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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Joint attention is a fundamental cognitive ability that supports daily interpersonal relationships and communication. The Parallel Distributed Processing model (PDPM) postulates that responding to (RJA) and initiating (IJA) joint attention are predominantly supported by posterior-parietal and frontal regions respectively. It also argues that these neural networks integrate during development, supporting the parallel processes of self- and other-attention representation during interactions. However, direct evidence for the PDPM is limited due to a lack of ecologically valid experimental paradigms that can capture both RJA and IJA. Building on existing interactive approaches, we developed a virtual reality paradigm where participants engaged in an online interaction to complete a cooperative task. By including tightly controlled baseline conditions to remove activity associated with non-social task demands, we were able to directly contrast the neural correlates of RJA and IJA to determine whether these processes are supported by common brain regions. Both RJA and IJA activated broad frontotemporoparietal networks. Critically, a conjunction analysis identified that a subset of these regions were common to both RJA and IJA. This right-lateralised network included the dorsal portion of the middle frontal gyrus (MFG), inferior frontal gyrus (IFG), middle temporal gyrus (MTG), precentral gyrus, posterior superior temporal sulcus (pSTS), temporoparietal junction (TPJ) and precuneus. Additional activation was observed in this network for IJA relative to RJA at MFG, IFG, TPJ and precuneus. This is the first imaging study to directly investigate the neural correlates common to RJA and IJA engagement, and thus support the assumption that a broad integrated network underlies the parallel aspects of both initiating and responding to joint attention. |
Wonil Choi; Rutvik H Desai; John M Henderson The neural substrates of natural reading: A comparison of normal and nonword text using eyetracking and fMRI Journal Article Frontiers in Human Neuroscience, 8 , pp. 1–11, 2014. Abstract | Links | BibTeX @article{Choi2014b,
title = {The neural substrates of natural reading: A comparison of normal and nonword text using eyetracking and fMRI},
author = {Wonil Choi and Rutvik H Desai and John M Henderson},
url = {http://journal.frontiersin.org/article/10.3389/fnhum.2014.01024/abstract},
doi = {10.3389/fnhum.2014.01024},
year = {2014},
date = {2014-01-01},
journal = {Frontiers in Human Neuroscience},
volume = {8},
pages = {1--11},
abstract = {Most previous studies investigating the neural correlates of reading have presented text using serial visual presentation (SVP), which may not fully reflect the underlying processes of natural reading. In the present study, eye movements and BOLD data were collected while subjects either read normal paragraphs naturally or moved their eyes through "paragraphs" of pseudo-text (pronounceable pseudowords or consonant letter strings) in two pseudo-reading conditions. Eye movement data established that subjects were reading and scanning the stimuli normally. A conjunction fMRI analysis across natural- and pseudo-reading showed that a common eye-movement network including frontal eye fields (FEF), supplementary eye fields (SEF), and intraparietal sulci was activated, consistent with previous studies using simpler eye movement tasks. In addition, natural reading versus pseudo-reading showed different patterns of brain activation: normal reading produced activation in a well-established language network that included superior temporal gyrus/sulcus, middle temporal gyrus (MTG), angular gyrus (AG), inferior frontal gyrus, and middle frontal gyrus, whereas pseudo-reading produced activation in an attentional network that included anterior/posterior cingulate and parietal cortex. These results are consistent with results found in previous single-saccade eye movement tasks and SVP reading studies, suggesting that component processes of eye-movement control and language processing observed in past fMRI research generalize to natural reading. The results also suggest that combining eyetracking and fMRI is a suitable method for investigating the component processes of natural reading in fMRI research.},
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Most previous studies investigating the neural correlates of reading have presented text using serial visual presentation (SVP), which may not fully reflect the underlying processes of natural reading. In the present study, eye movements and BOLD data were collected while subjects either read normal paragraphs naturally or moved their eyes through "paragraphs" of pseudo-text (pronounceable pseudowords or consonant letter strings) in two pseudo-reading conditions. Eye movement data established that subjects were reading and scanning the stimuli normally. A conjunction fMRI analysis across natural- and pseudo-reading showed that a common eye-movement network including frontal eye fields (FEF), supplementary eye fields (SEF), and intraparietal sulci was activated, consistent with previous studies using simpler eye movement tasks. In addition, natural reading versus pseudo-reading showed different patterns of brain activation: normal reading produced activation in a well-established language network that included superior temporal gyrus/sulcus, middle temporal gyrus (MTG), angular gyrus (AG), inferior frontal gyrus, and middle frontal gyrus, whereas pseudo-reading produced activation in an attentional network that included anterior/posterior cingulate and parietal cortex. These results are consistent with results found in previous single-saccade eye movement tasks and SVP reading studies, suggesting that component processes of eye-movement control and language processing observed in past fMRI research generalize to natural reading. The results also suggest that combining eyetracking and fMRI is a suitable method for investigating the component processes of natural reading in fMRI research. |
Wonil Choi; John M Henderson Neural correlates of active vision: An fMRI comparison of natural reading and scene viewing Journal Article Neuropsychologia, 75 , pp. 109–118, 2015. Abstract | Links | BibTeX @article{Choi2015,
title = {Neural correlates of active vision: An fMRI comparison of natural reading and scene viewing},
author = {Wonil Choi and John M Henderson},
url = {http://dx.doi.org/10.1016/j.neuropsychologia.2015.05.027},
doi = {10.1016/j.neuropsychologia.2015.05.027},
year = {2015},
date = {2015-01-01},
journal = {Neuropsychologia},
volume = {75},
pages = {109--118},
publisher = {Elsevier},
abstract = {Theories of eye movement control during active vision tasks such as reading and scene viewing have primarily been developed and tested using data from eye tracking and computational modeling, and little is currently known about the neurocognition of active vision. The current fMRI study was conducted to examine the nature of the cortical networks that are associated with active vision. Subjects were asked to read passages for meaning and view photographs of scenes for a later memory test. The eye movement control network comprising frontal eye field (FEF), supplementary eye fields (SEF), and intraparietal sulcus (IPS), commonly activated during single-saccade eye movement tasks, were also involved in reading and scene viewing, suggesting that a common control network is engaged when eye movements are executed. However, the activated locus of the FEF varied across the two tasks, with medial FEF more activated in scene viewing relative to passage reading and lateral FEF more activated in reading than scene viewing. The results suggest that eye movements during active vision are associated with both domain-general and domain-specific components of the eye movement control network.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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Theories of eye movement control during active vision tasks such as reading and scene viewing have primarily been developed and tested using data from eye tracking and computational modeling, and little is currently known about the neurocognition of active vision. The current fMRI study was conducted to examine the nature of the cortical networks that are associated with active vision. Subjects were asked to read passages for meaning and view photographs of scenes for a later memory test. The eye movement control network comprising frontal eye field (FEF), supplementary eye fields (SEF), and intraparietal sulcus (IPS), commonly activated during single-saccade eye movement tasks, were also involved in reading and scene viewing, suggesting that a common control network is engaged when eye movements are executed. However, the activated locus of the FEF varied across the two tasks, with medial FEF more activated in scene viewing relative to passage reading and lateral FEF more activated in reading than scene viewing. The results suggest that eye movements during active vision are associated with both domain-general and domain-specific components of the eye movement control network. |
Heeyoung Choo; Dirk B Walther Contour junctions underlie neural representations of scene categories in high-level human visual cortex: Contour junctions underlie neural representations of scenes Journal Article NeuroImage, 135 , pp. 32–44, 2016. Abstract | Links | BibTeX @article{Choo2016,
title = {Contour junctions underlie neural representations of scene categories in high-level human visual cortex: Contour junctions underlie neural representations of scenes},
author = {Heeyoung Choo and Dirk B Walther},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.04.021},
doi = {10.1016/j.neuroimage.2016.04.021},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {135},
pages = {32--44},
publisher = {Elsevier Inc.},
abstract = {Humans efficiently grasp complex visual environments, making highly consistent judgments of entry-level category despite their high variability in visual appearance. How does the human brain arrive at the invariant neural representations underlying categorization of real-world environments? We here show that the neural representation of visual environments in scene-selective human visual cortex relies on statistics of contour junctions, which provide cues for the three-dimensional arrangement of surfaces in a scene. We manipulated line drawings of real-world environments such that statistics of contour orientations or junctions were disrupted. Manipulated and intact line drawings were presented to participants in an fMRI experiment. Scene categories were decoded from neural activity patterns in the parahippocampal place area (PPA), the occipital place area (OPA) and other visual brain regions. Disruption of junctions but not orientations led to a drastic decrease in decoding accuracy in the PPA and OPA, indicating the reliance of these areas on intact junction statistics. Accuracy of decoding from early visual cortex, on the other hand, was unaffected by either image manipulation. We further show that the correlation of error patterns between decoding from the scene-selective brain areas and behavioral experiments is contingent on intact contour junctions. Finally, a searchlight analysis exposes the reliance of visually active brain regions on different sets of contour properties. Statistics of contour length and curvature dominate neural representations of scene categories in early visual areas and contour junctions in high-level scene-selective brain regions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Humans efficiently grasp complex visual environments, making highly consistent judgments of entry-level category despite their high variability in visual appearance. How does the human brain arrive at the invariant neural representations underlying categorization of real-world environments? We here show that the neural representation of visual environments in scene-selective human visual cortex relies on statistics of contour junctions, which provide cues for the three-dimensional arrangement of surfaces in a scene. We manipulated line drawings of real-world environments such that statistics of contour orientations or junctions were disrupted. Manipulated and intact line drawings were presented to participants in an fMRI experiment. Scene categories were decoded from neural activity patterns in the parahippocampal place area (PPA), the occipital place area (OPA) and other visual brain regions. Disruption of junctions but not orientations led to a drastic decrease in decoding accuracy in the PPA and OPA, indicating the reliance of these areas on intact junction statistics. Accuracy of decoding from early visual cortex, on the other hand, was unaffected by either image manipulation. We further show that the correlation of error patterns between decoding from the scene-selective brain areas and behavioral experiments is contingent on intact contour junctions. Finally, a searchlight analysis exposes the reliance of visually active brain regions on different sets of contour properties. Statistics of contour length and curvature dominate neural representations of scene categories in early visual areas and contour junctions in high-level scene-selective brain regions. |
S Clavagnier; S O Dumoulin; R F Hess Is the cortical deficit in amblyopia due to reduced cortical magnification, loss of neural resolution, or neural disorganization? Journal Article Journal of Neuroscience, 35 (44), pp. 14740–14755, 2015. Abstract | Links | BibTeX @article{Clavagnier2015,
title = {Is the cortical deficit in amblyopia due to reduced cortical magnification, loss of neural resolution, or neural disorganization?},
author = {S Clavagnier and S O Dumoulin and R F Hess},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.1101-15.2015},
doi = {10.1523/JNEUROSCI.1101-15.2015},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neuroscience},
volume = {35},
number = {44},
pages = {14740--14755},
abstract = {The neural basis of amblyopia is a matter of debate. The following possibilities have been suggested: loss of foveal cells, reduced cortical magnification, loss of spatial resolution of foveal cells, and topographical disarray in the cellular map. To resolve this we undertook a population receptive field (pRF) functional magnetic resonance imaging analysis in the central field in humans with moderate-to-severe amblyopia. We measured the relationship between averaged pRF size and retinal eccentricity in retinotopic visual areas. Results showed that cortical magnification is normal in the foveal field of strabismic amblyopes. However, the pRF sizes are enlarged for the amblyopic eye. We speculate that the pRF enlargement reflects loss of cellular resolution or an increased cellular positional disarray within the representation of the amblyopic eye.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The neural basis of amblyopia is a matter of debate. The following possibilities have been suggested: loss of foveal cells, reduced cortical magnification, loss of spatial resolution of foveal cells, and topographical disarray in the cellular map. To resolve this we undertook a population receptive field (pRF) functional magnetic resonance imaging analysis in the central field in humans with moderate-to-severe amblyopia. We measured the relationship between averaged pRF size and retinal eccentricity in retinotopic visual areas. Results showed that cortical magnification is normal in the foveal field of strabismic amblyopes. However, the pRF sizes are enlarged for the amblyopic eye. We speculate that the pRF enlargement reflects loss of cellular resolution or an increased cellular positional disarray within the representation of the amblyopic eye. |
Brian A Coffman; Piyadasa Kodituwakku; Elizabeth L Kodituwakku; Lucinda Romero; Nirupama Muniswamy Sharadamma; David Stone; Julia M Stephen Primary visual response (M100) delays in adolescents with FASD as measured with MEG Journal Article Human Brain Mapping, 34 (11), pp. 2852–2862, 2013. Abstract | Links | BibTeX @article{Coffman2013,
title = {Primary visual response (M100) delays in adolescents with FASD as measured with MEG},
author = {Brian A Coffman and Piyadasa Kodituwakku and Elizabeth L Kodituwakku and Lucinda Romero and Nirupama Muniswamy Sharadamma and David Stone and Julia M Stephen},
doi = {10.1002/hbm.22110},
year = {2013},
date = {2013-01-01},
journal = {Human Brain Mapping},
volume = {34},
number = {11},
pages = {2852--2862},
abstract = {Fetal alcohol spectrum disorders (FASD) are debilitating, with effects of prenatal alcohol exposure persisting into adolescence and adulthood. Complete characterization of FASD is crucial for the development of diagnostic tools and intervention techniques to decrease the high cost to individual families and society of this disorder. In this experiment, we investigated visual system deficits in adolescents (12-21 years) diagnosed with an FASD by measuring the latency of patients' primary visual M100 responses using MEG. We hypothesized that patients with FASD would demonstrate delayed primary visual responses compared to controls. M100 latencies were assessed both for FASD patients and age-matched healthy controls for stimuli presented at the fovea (central stimulus) and at the periphery (peripheral stimuli; left or right of the central stimulus) in a saccade task requiring participants to direct their attention and gaze to these stimuli. Source modeling was performed on visual responses to the central and peripheral stimuli and the latency of the first prominent peak (M100) in the occipital source timecourse was identified. The peak latency of the M100 responses were delayed in FASD patients for both stimulus types (central and peripheral), but the difference in latency of primary visual responses to central vs. peripheral stimuli was significant only in FASD patients, indicating that, while FASD patients' visual systems are impaired in general, this impairment is more pronounced in the periphery. These results suggest that basic sensory deficits in this population may contribute to sensorimotor integration deficits described previously in this disorder.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fetal alcohol spectrum disorders (FASD) are debilitating, with effects of prenatal alcohol exposure persisting into adolescence and adulthood. Complete characterization of FASD is crucial for the development of diagnostic tools and intervention techniques to decrease the high cost to individual families and society of this disorder. In this experiment, we investigated visual system deficits in adolescents (12-21 years) diagnosed with an FASD by measuring the latency of patients' primary visual M100 responses using MEG. We hypothesized that patients with FASD would demonstrate delayed primary visual responses compared to controls. M100 latencies were assessed both for FASD patients and age-matched healthy controls for stimuli presented at the fovea (central stimulus) and at the periphery (peripheral stimuli; left or right of the central stimulus) in a saccade task requiring participants to direct their attention and gaze to these stimuli. Source modeling was performed on visual responses to the central and peripheral stimuli and the latency of the first prominent peak (M100) in the occipital source timecourse was identified. The peak latency of the M100 responses were delayed in FASD patients for both stimulus types (central and peripheral), but the difference in latency of primary visual responses to central vs. peripheral stimuli was significant only in FASD patients, indicating that, while FASD patients' visual systems are impaired in general, this impairment is more pronounced in the periphery. These results suggest that basic sensory deficits in this population may contribute to sensorimotor integration deficits described previously in this disorder. |
Rutvik H Desai; Wonil Choi; Vicky T Lai; John M Henderson Toward semantics in the wild: Activation to manipulable nouns in naturalistic reading Journal Article Journal of Neuroscience, 36 (14), pp. 4050–4055, 2016. Abstract | Links | BibTeX @article{Desai2016,
title = {Toward semantics in the wild: Activation to manipulable nouns in naturalistic reading},
author = {Rutvik H Desai and Wonil Choi and Vicky T Lai and John M Henderson},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.1480-15.2016},
doi = {10.1523/JNEUROSCI.1480-15.2016},
year = {2016},
date = {2016-01-01},
journal = {Journal of Neuroscience},
volume = {36},
number = {14},
pages = {4050--4055},
abstract = {The neural basis of language processing, in the context of naturalistic reading of connected text, is a crucial but largely unexplored area. Here we combined functional MRI and eye tracking to examine the reading of text presented as whole paragraphs in two experiments with human subjects. We registered high-temporal resolution eye-tracking data to a low-temporal resolution BOLD signal to extract responses to single words during naturalistic reading where two to four words are typically processed per second. As a test case of a lexical variable, we examined the response to noun manipulability. In both experiments, signal in the left anterior inferior parietal lobule and posterior inferior temporal gyrus and sulcus was positively correlated with noun manipulability. These regions are associated with both action performance and action semantics, and their activation is consistent with a number of previous studies involving tool words and physical tool use. The results show that even during rapid reading of connected text, where semantics of words may be activated only partially, the meaning of manipulable nouns is grounded in action performance systems. This supports the grounded cognition view of semantics, which posits a close link between sensory-motor and conceptual systems of the brain. On the methodological front, these results demonstrate that BOLD responses to lexical variables during naturalistic reading can be extracted by simultaneous use of eye tracking. This opens up new avenues for the study of language and reading in the context of connected text.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The neural basis of language processing, in the context of naturalistic reading of connected text, is a crucial but largely unexplored area. Here we combined functional MRI and eye tracking to examine the reading of text presented as whole paragraphs in two experiments with human subjects. We registered high-temporal resolution eye-tracking data to a low-temporal resolution BOLD signal to extract responses to single words during naturalistic reading where two to four words are typically processed per second. As a test case of a lexical variable, we examined the response to noun manipulability. In both experiments, signal in the left anterior inferior parietal lobule and posterior inferior temporal gyrus and sulcus was positively correlated with noun manipulability. These regions are associated with both action performance and action semantics, and their activation is consistent with a number of previous studies involving tool words and physical tool use. The results show that even during rapid reading of connected text, where semantics of words may be activated only partially, the meaning of manipulable nouns is grounded in action performance systems. This supports the grounded cognition view of semantics, which posits a close link between sensory-motor and conceptual systems of the brain. On the methodological front, these results demonstrate that BOLD responses to lexical variables during naturalistic reading can be extracted by simultaneous use of eye tracking. This opens up new avenues for the study of language and reading in the context of connected text. |
Jelle A van Dijk; Benjamin de Haas; Christina Moutsiana; Samuel D Schwarzkopf Intersession reliability of population receptive field estimates Journal Article NeuroImage, 143 , pp. 293–303, 2016. Abstract | Links | BibTeX @article{Dijk2016,
title = {Intersession reliability of population receptive field estimates},
author = {Jelle A van Dijk and Benjamin de Haas and Christina Moutsiana and Samuel D Schwarzkopf},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.09.013},
doi = {10.1016/j.neuroimage.2016.09.013},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {143},
pages = {293--303},
publisher = {Elsevier},
abstract = {Population receptive field (pRF) analysis is a popular method to infer spatial selectivity of voxels in visual cortex. However, it remains largely untested how stable pRF estimates are over time. Here we measured the intersession reliability of pRF parameter estimates for the central visual field and near periphery, using a combined wedge and ring stimulus containing natural images. Sixteen healthy human participants completed two scanning sessions separated by 10–114 days. Individual participants showed very similar visual field maps for V1-V4 on both sessions. Intersession reliability for eccentricity and polar angle estimates was close to ceiling for most visual field maps (rtextgreater.8 for V1-3). PRF size and cortical magnification (CMF) estimates showed strong but lower overall intersession reliability (r≈.4–.6). Group level results for pRF size and CMF were highly similar between sessions. Additional control experiments confirmed that reliability does not depend on the carrier stimulus used and that reliability for pRF size and CMF is high for sessions acquired on the same day (rtextgreater.6). Our results demonstrate that pRF mapping is highly reliable across sessions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Population receptive field (pRF) analysis is a popular method to infer spatial selectivity of voxels in visual cortex. However, it remains largely untested how stable pRF estimates are over time. Here we measured the intersession reliability of pRF parameter estimates for the central visual field and near periphery, using a combined wedge and ring stimulus containing natural images. Sixteen healthy human participants completed two scanning sessions separated by 10–114 days. Individual participants showed very similar visual field maps for V1-V4 on both sessions. Intersession reliability for eccentricity and polar angle estimates was close to ceiling for most visual field maps (rtextgreater.8 for V1-3). PRF size and cortical magnification (CMF) estimates showed strong but lower overall intersession reliability (r≈.4–.6). Group level results for pRF size and CMF were highly similar between sessions. Additional control experiments confirmed that reliability does not depend on the carrier stimulus used and that reliability for pRF size and CMF is high for sessions acquired on the same day (rtextgreater.6). Our results demonstrate that pRF mapping is highly reliable across sessions. |
Mithun Diwakar; Deborah L Harrington; Jun Maruta; Jamshid Ghajar; Fady El-Gabalawy; Laura Muzzatti; Maurizio Corbetta; Ming-xiong Xiong Huang; Roland R Lee Filling in the gaps: Anticipatory control of eye movements in chronic mild traumatic brain injury Journal Article NeuroImage: Clinical, 8 , pp. 210–223, 2015. Abstract | Links | BibTeX @article{Diwakar2015,
title = {Filling in the gaps: Anticipatory control of eye movements in chronic mild traumatic brain injury},
author = {Mithun Diwakar and Deborah L Harrington and Jun Maruta and Jamshid Ghajar and Fady El-Gabalawy and Laura Muzzatti and Maurizio Corbetta and Ming-xiong Xiong Huang and Roland R Lee},
url = {http://dx.doi.org/10.1016/j.nicl.2015.04.011},
doi = {10.1016/j.nicl.2015.04.011},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage: Clinical},
volume = {8},
pages = {210--223},
publisher = {Elsevier B.V.},
abstract = {A barrier in the diagnosis of mild traumatic brain injury (mTBI) stems from the lack of measures that are adequately sensitive in detecting mild head injuries. MRI and CT are typically negative in mTBI patients with persistent symptoms of post-concussive syndrome (PCS), and characteristic difficulties in sustaining attention often go undetected on neuropsychological testing, which can be insensitive to momentary lapses in concentration. Conversely, visual tracking strongly depends on sustained attention over time and is impaired in chronic mTBI patients, especially when tracking an occluded target. This finding suggests deficient internal anticipatory control in mTBI, the neural underpinnings of which are poorly understood. The present study investigated the neuronal bases for deficient anticipatory control during visual tracking in 25 chronic mTBI patients with persistent PCS symptoms and 25 healthy control subjects. The task was performed while undergoing magnetoencephalography (MEG), which allowed us to examine whether neural dysfunction associated with anticipatory control deficits was due to altered alpha, beta, and/or gamma activity. Neuropsychological examinations characterized cognition in both groups. During MEG recordings, subjects tracked a predictably moving target that was either continuously visible or randomly occluded (gap condition). MEG source-imaging analyses tested for group differences in alpha, beta, and gamma frequency bands. The results showed executive functioning, information processing speed, and verbal memory deficits in the mTBI group. Visual tracking was impaired in the mTBI group only in the gap condition. Patients showed greater error than controls before and during target occlusion, and were slower to resynchronize with the target when it reappeared. Impaired tracking concurred with abnormal beta activity, which was suppressed in the parietal cortex, especially the right hemisphere, and enhanced in left caudate and frontaloral areas. Regional beta-amplitude demonstrated high classification accuracy (92%) compared to eye-tracking (65%) and neuropsychological variables (80%). These findings show that deficient internal anticipatory control in mTBI is associated with altered beta activity, which is remarkably sensitive given the heterogeneity of injuries.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A barrier in the diagnosis of mild traumatic brain injury (mTBI) stems from the lack of measures that are adequately sensitive in detecting mild head injuries. MRI and CT are typically negative in mTBI patients with persistent symptoms of post-concussive syndrome (PCS), and characteristic difficulties in sustaining attention often go undetected on neuropsychological testing, which can be insensitive to momentary lapses in concentration. Conversely, visual tracking strongly depends on sustained attention over time and is impaired in chronic mTBI patients, especially when tracking an occluded target. This finding suggests deficient internal anticipatory control in mTBI, the neural underpinnings of which are poorly understood. The present study investigated the neuronal bases for deficient anticipatory control during visual tracking in 25 chronic mTBI patients with persistent PCS symptoms and 25 healthy control subjects. The task was performed while undergoing magnetoencephalography (MEG), which allowed us to examine whether neural dysfunction associated with anticipatory control deficits was due to altered alpha, beta, and/or gamma activity. Neuropsychological examinations characterized cognition in both groups. During MEG recordings, subjects tracked a predictably moving target that was either continuously visible or randomly occluded (gap condition). MEG source-imaging analyses tested for group differences in alpha, beta, and gamma frequency bands. The results showed executive functioning, information processing speed, and verbal memory deficits in the mTBI group. Visual tracking was impaired in the mTBI group only in the gap condition. Patients showed greater error than controls before and during target occlusion, and were slower to resynchronize with the target when it reappeared. Impaired tracking concurred with abnormal beta activity, which was suppressed in the parietal cortex, especially the right hemisphere, and enhanced in left caudate and frontaloral areas. Regional beta-amplitude demonstrated high classification accuracy (92%) compared to eye-tracking (65%) and neuropsychological variables (80%). These findings show that deficient internal anticipatory control in mTBI is associated with altered beta activity, which is remarkably sensitive given the heterogeneity of injuries. |
Pascasie L Dombert; Anna Kuhns; Paola Mengotti; Gereon R Fink; Simone Vossel Functional mechanisms of probabilistic inference in feature- and space-based attentional systems Journal Article NeuroImage, 142 , pp. 553–564, 2016. Abstract | Links | BibTeX @article{Dombert2016a,
title = {Functional mechanisms of probabilistic inference in feature- and space-based attentional systems},
author = {Pascasie L Dombert and Anna Kuhns and Paola Mengotti and Gereon R Fink and Simone Vossel},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.08.010},
doi = {10.1016/j.neuroimage.2016.08.010},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {142},
pages = {553--564},
publisher = {Elsevier Inc.},
abstract = {Humans flexibly attend to features or locations and these processes are influenced by the probability of sensory events. We combined computational modeling of response times with fMRI to compare the functional correlates of (re-)orienting, and the modulation by probabilistic inference in spatial and feature-based attention systems. Twenty-four volunteers performed two task versions with spatial or color cues. Percentage of cue validity changed unpredictably. A hierarchical Bayesian model was used to derive trial-wise estimates of probability-dependent attention, entering the fMRI analysis as parametric regressors. Attentional orienting activated a dorsal frontoparietal network in both tasks, without significant parametric modulation. Spatially invalid trials activated a bilateral frontoparietal network and the precuneus, while invalid feature trials activated the left intraparietal sulcus (IPS). Probability-dependent attention modulated activity in the precuneus, left posterior IPS, middle occipital gyrus, and right temporoparietal junction for spatial attention, and in the left anterior IPS for feature-based and spatial attention. These findings provide novel insights into the generality and specificity of the functional basis of attentional control. They suggest that probabilistic inference can distinctively affect each attentional subsystem, but that there is an overlap in the left IPS, which responds to both spatial and feature-based expectancy violations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Humans flexibly attend to features or locations and these processes are influenced by the probability of sensory events. We combined computational modeling of response times with fMRI to compare the functional correlates of (re-)orienting, and the modulation by probabilistic inference in spatial and feature-based attention systems. Twenty-four volunteers performed two task versions with spatial or color cues. Percentage of cue validity changed unpredictably. A hierarchical Bayesian model was used to derive trial-wise estimates of probability-dependent attention, entering the fMRI analysis as parametric regressors. Attentional orienting activated a dorsal frontoparietal network in both tasks, without significant parametric modulation. Spatially invalid trials activated a bilateral frontoparietal network and the precuneus, while invalid feature trials activated the left intraparietal sulcus (IPS). Probability-dependent attention modulated activity in the precuneus, left posterior IPS, middle occipital gyrus, and right temporoparietal junction for spatial attention, and in the left anterior IPS for feature-based and spatial attention. These findings provide novel insights into the generality and specificity of the functional basis of attentional control. They suggest that probabilistic inference can distinctively affect each attentional subsystem, but that there is an overlap in the left IPS, which responds to both spatial and feature-based expectancy violations. |
João Valente Duarte; Gabriel Nascimento Costa; Ricardo Martins; Miguel Castelo-Branco Pivotal role of hMT+ in long-range disambiguation of interhemispheric bistable surface motion Journal Article Human Brain Mapping, 38 (10), pp. 4882–4897, 2017. Abstract | Links | BibTeX @article{Duarte2017,
title = {Pivotal role of hMT+ in long-range disambiguation of interhemispheric bistable surface motion},
author = {Jo{ã}o Valente Duarte and Gabriel Nascimento Costa and Ricardo Martins and Miguel Castelo-Branco},
doi = {10.1002/hbm.23701},
year = {2017},
date = {2017-01-01},
journal = {Human Brain Mapping},
volume = {38},
number = {10},
pages = {4882--4897},
abstract = {It remains an open question whether long-range disambiguation of ambiguous surface motion can be achieved in early visual cortex or instead in higher level regions, which concerns object/surface segmentation/integration mechanisms. We used a bistable moving stimulus that can be perceived as a pattern comprehending both visual hemi-fields moving coherently downward or as two widely segregated nonoverlapping component objects (in each visual hemi-field) moving separately inward. This paradigm requires long-range integration across the vertical meridian leading to interhemispheric binding. Our fMRI study (n = 30) revealed a close relation between activity in hMT+ and perceptual switches involving interhemispheric segregation/integration of motion signals, crucially under nonlocal conditions where components do not overlap and belong to distinct hemispheres. Higher signal changes were found in hMT+ in response to spatially segregated component (incoherent) percepts than to pattern (coherent) percepts. This did not occur in early visual cortex, unlike apparent motion, which does not entail surface segmentation. We also identified a role for top–down mechanisms in state transitions. Deconvolution analysis of switch-related changes revealed prefrontal, insula, and cingulate areas, with the right superior parietal lobule (SPL) being particularly involved. We observed that directed influences could emerge either from left or right hMT+ during bistable motion integration/segregation. SPL also exhibited significant directed functional connectivity with hMT+, during perceptual state maintenance (Granger causality analysis). Our results suggest that long-range interhemispheric binding of ambiguous motion representations mainly reflect bottom–up processes from hMT+ during perceptual state maintenance. In contrast, state transitions maybe influenced by high-level regions such as the SPL.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
It remains an open question whether long-range disambiguation of ambiguous surface motion can be achieved in early visual cortex or instead in higher level regions, which concerns object/surface segmentation/integration mechanisms. We used a bistable moving stimulus that can be perceived as a pattern comprehending both visual hemi-fields moving coherently downward or as two widely segregated nonoverlapping component objects (in each visual hemi-field) moving separately inward. This paradigm requires long-range integration across the vertical meridian leading to interhemispheric binding. Our fMRI study (n = 30) revealed a close relation between activity in hMT+ and perceptual switches involving interhemispheric segregation/integration of motion signals, crucially under nonlocal conditions where components do not overlap and belong to distinct hemispheres. Higher signal changes were found in hMT+ in response to spatially segregated component (incoherent) percepts than to pattern (coherent) percepts. This did not occur in early visual cortex, unlike apparent motion, which does not entail surface segmentation. We also identified a role for top–down mechanisms in state transitions. Deconvolution analysis of switch-related changes revealed prefrontal, insula, and cingulate areas, with the right superior parietal lobule (SPL) being particularly involved. We observed that directed influences could emerge either from left or right hMT+ during bistable motion integration/segregation. SPL also exhibited significant directed functional connectivity with hMT+, during perceptual state maintenance (Granger causality analysis). Our results suggest that long-range interhemispheric binding of ambiguous motion representations mainly reflect bottom–up processes from hMT+ during perceptual state maintenance. In contrast, state transitions maybe influenced by high-level regions such as the SPL. |
Grace Edwards; Petra Vetter; Fiona McGruer; Lucy S Petro; Lars Muckli Predictive feedback to V1 dynamically updates with sensory input Journal Article Scientific Reports, 7 (1), pp. 1–12, 2017. Abstract | Links | BibTeX @article{Edwards2017a,
title = {Predictive feedback to V1 dynamically updates with sensory input},
author = {Grace Edwards and Petra Vetter and Fiona McGruer and Lucy S Petro and Lars Muckli},
url = {http://dx.doi.org/10.1038/s41598-017-16093-y http://www.nature.com/articles/s41598-017-16093-y},
doi = {10.1038/s41598-017-16093-y},
year = {2017},
date = {2017-12-01},
journal = {Scientific Reports},
volume = {7},
number = {1},
pages = {1--12},
publisher = {Springer US},
abstract = {Predictive coding theories propose that the brain creates internal models of the environment to predict upcoming sensory input. Hierarchical predictive coding models of vision postulate that higher visual areas generate predictions of sensory inputs and feed them back to early visual cortex. In V1, sensory inputs that do not match the predictions lead to amplified brain activation, but does this amplification process dynamically update to new retinotopic locations with eye-movements? We investigated the effect of eye-movements in predictive feedback using functional brain imaging and eye-tracking whilst presenting an apparent motion illusion. Apparent motion induces an internal model of motion, during which sensory predictions of the illusory motion feed back to V1. We observed attenuated BOLD responses to predicted stimuli at the new post-saccadic location in V1. Therefore, pre-saccadic predictions update their retinotopic location in time for post-saccadic input, validating dynamic predictive coding theories in V1.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Predictive coding theories propose that the brain creates internal models of the environment to predict upcoming sensory input. Hierarchical predictive coding models of vision postulate that higher visual areas generate predictions of sensory inputs and feed them back to early visual cortex. In V1, sensory inputs that do not match the predictions lead to amplified brain activation, but does this amplification process dynamically update to new retinotopic locations with eye-movements? We investigated the effect of eye-movements in predictive feedback using functional brain imaging and eye-tracking whilst presenting an apparent motion illusion. Apparent motion induces an internal model of motion, during which sensory predictions of the illusory motion feed back to V1. We observed attenuated BOLD responses to predicted stimuli at the new post-saccadic location in V1. Therefore, pre-saccadic predictions update their retinotopic location in time for post-saccadic input, validating dynamic predictive coding theories in V1. |
Michiel van Elk; Michiel van Elk The left inferior parietal lobe represents stored hand-postures for object use and action prediction Journal Article Frontiers in Psychology, 5 , pp. 1–12, 2014. Abstract | Links | BibTeX @article{Elk2014,
title = {The left inferior parietal lobe represents stored hand-postures for object use and action prediction},
author = {Michiel van Elk and Michiel van Elk},
doi = {10.3389/fpsyg.2014.00333},
year = {2014},
date = {2014-01-01},
journal = {Frontiers in Psychology},
volume = {5},
pages = {1--12},
abstract = {Action semantics enables us to plan actions with objects and to predict others' object-directed actions as well. Previous studies have suggested that action semantics are represented in a fronto-parietal action network that has also been implicated to play a role in action observation. In the present fMRI study it was investigated how activity within this network changes as a function of the predictability of an action involving multiple objects and requiring the use of action semantics. Participants performed an action prediction task in which they were required to anticipate the use of a centrally presented object that could be moved to an associated target object (e.g., hammer-nail). The availability of actor information (i.e., presenting a hand grasping the central object) and the number of possible target objects (i.e., 0, 1, or 2 target objects) were independently manipulated, resulting in different levels of predictability. It was found that making an action prediction based on actor information resulted in an increased activation in the extrastriate body area (EBA) and the fronto-parietal action observation network (AON). Predicting actions involving a target object resulted in increased activation in the bilateral IPL and frontal motor areas. Within the AON, activity in the left inferior parietal lobe (IPL) and the left premotor cortex (PMC) increased as a function of the level of action predictability. Together these findings suggest that the left IPL represents stored hand-postures that can be used for planning object-directed actions and for predicting other's actions as well.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Action semantics enables us to plan actions with objects and to predict others' object-directed actions as well. Previous studies have suggested that action semantics are represented in a fronto-parietal action network that has also been implicated to play a role in action observation. In the present fMRI study it was investigated how activity within this network changes as a function of the predictability of an action involving multiple objects and requiring the use of action semantics. Participants performed an action prediction task in which they were required to anticipate the use of a centrally presented object that could be moved to an associated target object (e.g., hammer-nail). The availability of actor information (i.e., presenting a hand grasping the central object) and the number of possible target objects (i.e., 0, 1, or 2 target objects) were independently manipulated, resulting in different levels of predictability. It was found that making an action prediction based on actor information resulted in an increased activation in the extrastriate body area (EBA) and the fronto-parietal action observation network (AON). Predicting actions involving a target object resulted in increased activation in the bilateral IPL and frontal motor areas. Within the AON, activity in the left inferior parietal lobe (IPL) and the left premotor cortex (PMC) increased as a function of the level of action predictability. Together these findings suggest that the left IPL represents stored hand-postures that can be used for planning object-directed actions and for predicting other's actions as well. |
Abdurahman S Elkhetali; Ryan J Vaden; Sean M Pool; Kristina M Visscher Early visual cortex reflects initiation and maintenance of task set Journal Article NeuroImage, 107 , pp. 277–288, 2015. Abstract | Links | BibTeX @article{Elkhetali2015,
title = {Early visual cortex reflects initiation and maintenance of task set},
author = {Abdurahman S Elkhetali and Ryan J Vaden and Sean M Pool and Kristina M Visscher},
url = {http://dx.doi.org/10.1016/j.neuroimage.2014.11.061},
doi = {10.1016/j.neuroimage.2014.11.061},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage},
volume = {107},
pages = {277--288},
publisher = {Elsevier B.V.},
abstract = {The human brain is able to process information flexibly, depending on a person's task. The mechanisms underlying this ability to initiate and maintain a task set are not well understood, but they are important for understanding the flexibility of human behavior and developing therapies for disorders involving attention. Here we investigate the differential roles of early visual cortical areas in initiating and maintaining a task set.Using functional Magnetic Resonance Imaging (fMRI), we characterized three different components of task set-related, but trial-independent activity in retinotopically mapped areas of early visual cortex, while human participants performed attention demanding visual or auditory tasks. These trial-independent effects reflected: (1) maintenance of attention over a long duration, (2) orienting to a cue, and (3) initiation of a task set. Participants performed tasks that differed in the modality of stimulus to be attended (auditory or visual) and in whether there was a simultaneous distractor (auditory only, visual only, or simultaneous auditory and visual). We found that patterns of trial-independent activity in early visual areas (V1, V2, V3, hV4) depend on attended modality, but not on stimuli. Further, different early visual areas play distinct roles in the initiation of a task set. In addition, activity associated with maintaining a task set tracks with a participant's behavior. These results show that trial-independent activity in early visual cortex reflects initiation and maintenance of a person's task set.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The human brain is able to process information flexibly, depending on a person's task. The mechanisms underlying this ability to initiate and maintain a task set are not well understood, but they are important for understanding the flexibility of human behavior and developing therapies for disorders involving attention. Here we investigate the differential roles of early visual cortical areas in initiating and maintaining a task set.Using functional Magnetic Resonance Imaging (fMRI), we characterized three different components of task set-related, but trial-independent activity in retinotopically mapped areas of early visual cortex, while human participants performed attention demanding visual or auditory tasks. These trial-independent effects reflected: (1) maintenance of attention over a long duration, (2) orienting to a cue, and (3) initiation of a task set. Participants performed tasks that differed in the modality of stimulus to be attended (auditory or visual) and in whether there was a simultaneous distractor (auditory only, visual only, or simultaneous auditory and visual). We found that patterns of trial-independent activity in early visual areas (V1, V2, V3, hV4) depend on attended modality, but not on stimuli. Further, different early visual areas play distinct roles in the initiation of a task set. In addition, activity associated with maintaining a task set tracks with a participant's behavior. These results show that trial-independent activity in early visual cortex reflects initiation and maintenance of a person's task set. |
Nathan Faivre; Sylvain Charron; Paul Roux; Stephane Lehericy; Sid Kouider Nonconscious emotional processing involves distinct neural pathways for pictures and videos Journal Article Neuropsychologia, 50 , pp. 3736–3744, 2012. Abstract | Links | BibTeX @article{Faivre2012a,
title = {Nonconscious emotional processing involves distinct neural pathways for pictures and videos},
author = {Nathan Faivre and Sylvain Charron and Paul Roux and Stephane Lehericy and Sid Kouider},
doi = {10.1016/j.neuropsychologia.2012.10.025},
year = {2012},
date = {2012-01-01},
journal = {Neuropsychologia},
volume = {50},
pages = {3736--3744},
abstract = {Facial expressions are known to impact observers' behavior, even when they are not consciously identifiable. Relying on visual crowding, a perceptual phenomenon whereby peripheral faces become undiscriminable, we show that participants exposed to happy vs. neutral crowded faces rated the pleasantness of subsequent neutral targets accordingly to the facial expression's valence. Using functional magnetic resonance imaging (fMRI) along with psychophysiological interaction analysis, we investigated the neural determinants of this nonconscious preference bias, either induced by static (i.e., pictures) or dynamic (i.e., videos) facial expressions. We found that while static expressions activated primarily the ventral visual pathway (including task-related functional connectivity between the fusiform face area and the amygdala), dynamic expressions triggered the dorsal visual pathway (i.e., posterior partietal cortex) and the substantia innominata, a structure that is contiguous with the dorsal amygdala. As temporal cues are known to improve the processing of visible facial expressions, the absence of ventral activation we observed with crowded videos questions the capacity to integrate facial features and facial motions without awareness. Nevertheless, both static and dynamic facial expressions activated the hippocampus and the orbitofrontal cortex, suggesting that nonconscious preference judgments may arise from the evaluation of emotional context and the computation of aesthetic evaluation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Facial expressions are known to impact observers' behavior, even when they are not consciously identifiable. Relying on visual crowding, a perceptual phenomenon whereby peripheral faces become undiscriminable, we show that participants exposed to happy vs. neutral crowded faces rated the pleasantness of subsequent neutral targets accordingly to the facial expression's valence. Using functional magnetic resonance imaging (fMRI) along with psychophysiological interaction analysis, we investigated the neural determinants of this nonconscious preference bias, either induced by static (i.e., pictures) or dynamic (i.e., videos) facial expressions. We found that while static expressions activated primarily the ventral visual pathway (including task-related functional connectivity between the fusiform face area and the amygdala), dynamic expressions triggered the dorsal visual pathway (i.e., posterior partietal cortex) and the substantia innominata, a structure that is contiguous with the dorsal amygdala. As temporal cues are known to improve the processing of visible facial expressions, the absence of ventral activation we observed with crowded videos questions the capacity to integrate facial features and facial motions without awareness. Nevertheless, both static and dynamic facial expressions activated the hippocampus and the orbitofrontal cortex, suggesting that nonconscious preference judgments may arise from the evaluation of emotional context and the computation of aesthetic evaluation. |
Jamie Ferri; Joseph Schmidt; Greg Hajcak; Turhan Canli Neural correlates of attentional deployment within unpleasant pictures Journal Article NeuroImage, 70 , pp. 268–277, 2013. Abstract | Links | BibTeX @article{Ferri2013,
title = {Neural correlates of attentional deployment within unpleasant pictures},
author = {Jamie Ferri and Joseph Schmidt and Greg Hajcak and Turhan Canli},
url = {http://dx.doi.org/10.1016/j.neuroimage.2012.12.030},
doi = {10.1016/j.neuroimage.2012.12.030},
year = {2013},
date = {2013-01-01},
journal = {NeuroImage},
volume = {70},
pages = {268--277},
publisher = {Elsevier Inc.},
abstract = {Attentional deployment is an emotion regulation strategy that involves shifting attentional focus towards or away from particular aspects of emotional stimuli. Previous studies have highlighted the prevalence of attentional deployment and demonstrated that it can have a significant impact on brain activity and behavior. However, little is known about the neural correlates of this strategy. The goal of the present studies was to examine the effect of attentional deployment on neural activity by directing attention to more or less arousing portions of unpleasant images. In Studies 1 and 2, participants passively viewed counterbalanced blocks of unpleasant images without a focus, unpleasant images with an arousing focus, unpleasant images with a non-arousing focus, neutral images without a focus, and neutral images with a non-arousing focus for 4000. ms each. In Study 2, eye-tracking data were collected on all participants during image acquisition. In both studies, affect ratings following each block indicated that participants felt significantly less negative affect after viewing unpleasant images with a non-arousing focus compared to unpleasant images with an arousing focus. In both studies, the unpleasant non-arousing focus condition compared to the unpleasant arousing focus condition was associated with increased activity in frontal and parietal regions implicated in inhibitory control and visual attention. In Study 2, the unpleasant non-arousing focus condition compared to the unpleasant arousing focus condition was associated with reduced activity in the amygdala and visual cortex. Collectively these data suggest that attending to a non-arousing portion of an unpleasant image successfully reduces subjective negative affect and recruits fronto-parietal networks implicated in inhibitory control. Moreover, when ensuring task compliance by monitoring eye movements, attentional deployment modulates amygdala activity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Attentional deployment is an emotion regulation strategy that involves shifting attentional focus towards or away from particular aspects of emotional stimuli. Previous studies have highlighted the prevalence of attentional deployment and demonstrated that it can have a significant impact on brain activity and behavior. However, little is known about the neural correlates of this strategy. The goal of the present studies was to examine the effect of attentional deployment on neural activity by directing attention to more or less arousing portions of unpleasant images. In Studies 1 and 2, participants passively viewed counterbalanced blocks of unpleasant images without a focus, unpleasant images with an arousing focus, unpleasant images with a non-arousing focus, neutral images without a focus, and neutral images with a non-arousing focus for 4000. ms each. In Study 2, eye-tracking data were collected on all participants during image acquisition. In both studies, affect ratings following each block indicated that participants felt significantly less negative affect after viewing unpleasant images with a non-arousing focus compared to unpleasant images with an arousing focus. In both studies, the unpleasant non-arousing focus condition compared to the unpleasant arousing focus condition was associated with increased activity in frontal and parietal regions implicated in inhibitory control and visual attention. In Study 2, the unpleasant non-arousing focus condition compared to the unpleasant arousing focus condition was associated with reduced activity in the amygdala and visual cortex. Collectively these data suggest that attending to a non-arousing portion of an unpleasant image successfully reduces subjective negative affect and recruits fronto-parietal networks implicated in inhibitory control. Moreover, when ensuring task compliance by monitoring eye movements, attentional deployment modulates amygdala activity. |
Jamie Ferri; Joseph Schmidt; Greg Hajcak; Turhan Canli Emotion regulation and amygdala-precuneus connectivity: Focusing on attentional deployment Journal Article Cognitive, Affective and Behavioral Neuroscience, 16 (6), pp. 991–1002, 2016. Abstract | Links | BibTeX @article{Ferri2016,
title = {Emotion regulation and amygdala-precuneus connectivity: Focusing on attentional deployment},
author = {Jamie Ferri and Joseph Schmidt and Greg Hajcak and Turhan Canli},
url = {http://dx.doi.org/10.3758/s13415-016-0447-y},
doi = {10.3758/s13415-016-0447-y},
year = {2016},
date = {2016-01-01},
journal = {Cognitive, Affective and Behavioral Neuroscience},
volume = {16},
number = {6},
pages = {991--1002},
publisher = {Cognitive, Affective, & Behavioral Neuroscience},
abstract = {Attentional deployment is an emotion regulation strategy that involves shifting attentional focus. Deploying attention to non-arousing, compared to arousing, regions of unpleasant images has been associated with reduced negative affect, reduced amygdala activation, and increased activity in fronto-parietal control networks. The current study examined neural correlates and functional connectivity associated with using attentional deployment to increase negative affect (deploying attention towards arousing unpleasant informa- tion) or to decrease negative affect (deploying attention away from arousing unpleasant information), compared to naturally viewing unpleasant images, in 42 individuals while concur- rently monitoring eye movements. Directing attention to both arousing and non-arousing regions resulted in enhanced fronto-parietal activation compared to natural viewing, but only directing attention to non-arousing regions was associat- ed with changes in amygdala activation. There were no sig- nificant differences in connectivity between naturally viewing unpleasant images and focusing on arousing regions. However, naturally viewing unpleasant images, relative to fo- cusing on non-arousing regions, was associated with in- creased connectivity between the amygdala and visual cortex, while focusing on non-arousing regions of unpleasant images, compared to natural viewing, was associated with increased connectivity between the amygdala and the precuneus. Amygdala-precuneus connectivity correlated positively with eye-tracking measures of attentional deployment success and with trait reappraisal. Deploying attention away from arousing unpleasant information, then, may depend upon functional relationships between the amygdala and parietal regions im- plicated in attentional control. Furthermore, these relation- ships might relate to the ability to successfully implement attentional deployment, and the predisposition to utilize adap- tive emotion regulation strategies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Attentional deployment is an emotion regulation strategy that involves shifting attentional focus. Deploying attention to non-arousing, compared to arousing, regions of unpleasant images has been associated with reduced negative affect, reduced amygdala activation, and increased activity in fronto-parietal control networks. The current study examined neural correlates and functional connectivity associated with using attentional deployment to increase negative affect (deploying attention towards arousing unpleasant informa- tion) or to decrease negative affect (deploying attention away from arousing unpleasant information), compared to naturally viewing unpleasant images, in 42 individuals while concur- rently monitoring eye movements. Directing attention to both arousing and non-arousing regions resulted in enhanced fronto-parietal activation compared to natural viewing, but only directing attention to non-arousing regions was associat- ed with changes in amygdala activation. There were no sig- nificant differences in connectivity between naturally viewing unpleasant images and focusing on arousing regions. However, naturally viewing unpleasant images, relative to fo- cusing on non-arousing regions, was associated with in- creased connectivity between the amygdala and visual cortex, while focusing on non-arousing regions of unpleasant images, compared to natural viewing, was associated with increased connectivity between the amygdala and the precuneus. Amygdala-precuneus connectivity correlated positively with eye-tracking measures of attentional deployment success and with trait reappraisal. Deploying attention away from arousing unpleasant information, then, may depend upon functional relationships between the amygdala and parietal regions im- plicated in attentional control. Furthermore, these relation- ships might relate to the ability to successfully implement attentional deployment, and the predisposition to utilize adap- tive emotion regulation strategies. |
Nonie J Finlayson; Xiaoli Zhang; Julie D Golomb Differential patterns of 2D location versus depth decoding along the visual hierarchy Journal Article NeuroImage, 147 , pp. 507–516, 2017. Abstract | Links | BibTeX @article{Finlayson2017a,
title = {Differential patterns of 2D location versus depth decoding along the visual hierarchy},
author = {Nonie J Finlayson and Xiaoli Zhang and Julie D Golomb},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.12.039},
doi = {10.1016/j.neuroimage.2016.12.039},
year = {2017},
date = {2017-01-01},
journal = {NeuroImage},
volume = {147},
pages = {507--516},
publisher = {Elsevier},
abstract = {Visual information is initially represented as 2D images on the retina, but our brains are able to transform this input to perceive our rich 3D environment. While many studies have explored 2D spatial representations or depth perception in isolation, it remains unknown if or how these processes interact in human visual cortex. Here we used functional MRI and multi-voxel pattern analysis to investigate the relationship between 2D location and position-in-depth information. We stimulated different 3D locations in a blocked design: each location was defined by horizontal, vertical, and depth position. Participants remained fixated at the center of the screen while passively viewing the peripheral stimuli with red/green anaglyph glasses. Our results revealed a widespread, systematic transition throughout visual cortex. As expected, 2D location information (horizontal and vertical) could be strongly decoded in early visual areas, with reduced decoding higher along the visual hierarchy, consistent with known changes in receptive field sizes. Critically, we found that the decoding of position-in-depth information tracked inversely with the 2D location pattern, with the magnitude of depth decoding gradually increasing from intermediate to higher visual and category regions. Representations of 2D location information became increasingly location-tolerant in later areas, where depth information was also tolerant to changes in 2D location. We propose that spatial representations gradually transition from 2D-dominant to balanced 3D (2D and depth) along the visual hierarchy.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Visual information is initially represented as 2D images on the retina, but our brains are able to transform this input to perceive our rich 3D environment. While many studies have explored 2D spatial representations or depth perception in isolation, it remains unknown if or how these processes interact in human visual cortex. Here we used functional MRI and multi-voxel pattern analysis to investigate the relationship between 2D location and position-in-depth information. We stimulated different 3D locations in a blocked design: each location was defined by horizontal, vertical, and depth position. Participants remained fixated at the center of the screen while passively viewing the peripheral stimuli with red/green anaglyph glasses. Our results revealed a widespread, systematic transition throughout visual cortex. As expected, 2D location information (horizontal and vertical) could be strongly decoded in early visual areas, with reduced decoding higher along the visual hierarchy, consistent with known changes in receptive field sizes. Critically, we found that the decoding of position-in-depth information tracked inversely with the 2D location pattern, with the magnitude of depth decoding gradually increasing from intermediate to higher visual and category regions. Representations of 2D location information became increasingly location-tolerant in later areas, where depth information was also tolerant to changes in 2D location. We propose that spatial representations gradually transition from 2D-dominant to balanced 3D (2D and depth) along the visual hierarchy. |
Stefan Frässle; Sören Krach; Frieder Michel Paulus; Andreas Jansen Handedness is related to neural mechanisms underlying hemispheric lateralization of face processing Journal Article Scientific Reports, 6 , pp. 1–17, 2016. Abstract | Links | BibTeX @article{Fraessle2016,
title = {Handedness is related to neural mechanisms underlying hemispheric lateralization of face processing},
author = {Stefan Frässle and Sören Krach and Frieder Michel Paulus and Andreas Jansen},
url = {http://dx.doi.org/10.1038/srep27153},
doi = {10.1038/srep27153},
year = {2016},
date = {2016-01-01},
journal = {Scientific Reports},
volume = {6},
pages = {1--17},
publisher = {Nature Publishing Group},
abstract = {While the right-hemispheric lateralization of the face perception network is well established, recent evidence suggests that handedness affects the cerebral lateralization of face processing at the hierarchical level of the fusiform face area (FFA). However, the neural mechanisms underlying differential hemispheric lateralization of face perception in right- and left-handers are largely unknown. Using dynamic causal modeling (DCM) for fMRI, we aimed to unravel the putative processes that mediate handedness-related differences by investigating the effective connectivity in the bilateral core face perception network. Our results reveal an enhanced recruitment of the left FFA in left-handers compared to right-handers, as evidenced by more pronounced face-specific modulatory influences on both intra- and interhemispheric connections. As structural and physiological correlates of handedness- related differences in face processing, right- and left-handers varied with regard to their gray matter volume in the left fusiform gyrus and their pupil responses to face stimuli. Overall, these results describe how handedness is related to the lateralization of the core face perception network, and point to different neural mechanisms underlying face processing in right- and left-handers. In a wider context, this demonstrates the entanglement of structurally and functionally remote brain networks, suggesting a broader underlying process regulating brain lateralization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
While the right-hemispheric lateralization of the face perception network is well established, recent evidence suggests that handedness affects the cerebral lateralization of face processing at the hierarchical level of the fusiform face area (FFA). However, the neural mechanisms underlying differential hemispheric lateralization of face perception in right- and left-handers are largely unknown. Using dynamic causal modeling (DCM) for fMRI, we aimed to unravel the putative processes that mediate handedness-related differences by investigating the effective connectivity in the bilateral core face perception network. Our results reveal an enhanced recruitment of the left FFA in left-handers compared to right-handers, as evidenced by more pronounced face-specific modulatory influences on both intra- and interhemispheric connections. As structural and physiological correlates of handedness- related differences in face processing, right- and left-handers varied with regard to their gray matter volume in the left fusiform gyrus and their pupil responses to face stimuli. Overall, these results describe how handedness is related to the lateralization of the core face perception network, and point to different neural mechanisms underlying face processing in right- and left-handers. In a wider context, this demonstrates the entanglement of structurally and functionally remote brain networks, suggesting a broader underlying process regulating brain lateralization. |
Stefan Frässle; Frieder Michel Paulus; Sören Krach; Stefan Robert Schweinberger; Klaas Enno Stephan; Andreas Jansen Mechanisms of hemispheric lateralization: Asymmetric interhemispheric recruitment in the face perception network Journal Article NeuroImage, 124 , pp. 977–988, 2016. Abstract | Links | BibTeX @article{Fraessle2016a,
title = {Mechanisms of hemispheric lateralization: Asymmetric interhemispheric recruitment in the face perception network},
author = {Stefan Frässle and Frieder Michel Paulus and Sören Krach and Stefan Robert Schweinberger and Klaas Enno Stephan and Andreas Jansen},
url = {http://dx.doi.org/10.1016/j.neuroimage.2015.09.055},
doi = {10.1016/j.neuroimage.2015.09.055},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {124},
pages = {977--988},
publisher = {Elsevier Inc.},
abstract = {Perceiving human faces constitutes a fundamental ability of the human mind, integrating a wealth of information essential for social interactions in everyday life. Neuroimaging studies have unveiled a distributed neural network consisting of multiple brain regions in both hemispheres. Whereas the individual regions in the face perception network and the right-hemispheric dominance for face processing have been subject to intensive research, the functional integration among these regions and hemispheres has received considerably less attention. Using dynamic causal modeling (DCM) for fMRI, we analyzed the effective connectivity between the core regions in the face perception network of healthy humans to unveil the mechanisms underlying both intra- and interhemispheric integration. Our results suggest that the right-hemispheric lateralization of the network is due to an asymmetric face-specific interhemispheric recruitment at an early processing stage - that is, at the level of the occipital face area (OFA) but not the fusiform face area (FFA). As a structural correlate, we found that OFA gray matter volume was correlated with this asymmetric interhemispheric recruitment. Furthermore, exploratory analyses revealed that interhemispheric connection asymmetries were correlated with the strength of pupil constriction in response to faces, a measure with potential sensitivity to holistic (as opposed to feature-based) processing of faces. Overall, our findings thus provide a mechanistic description for lateralized processes in the core face perception network, point to a decisive role of interhemispheric integration at an early stage of face processing among bilateral OFA, and tentatively indicate a relation to individual variability in processing strategies for faces. These findings provide a promising avenue for systematic investigations of the potential role of interhemispheric integration in future studies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Perceiving human faces constitutes a fundamental ability of the human mind, integrating a wealth of information essential for social interactions in everyday life. Neuroimaging studies have unveiled a distributed neural network consisting of multiple brain regions in both hemispheres. Whereas the individual regions in the face perception network and the right-hemispheric dominance for face processing have been subject to intensive research, the functional integration among these regions and hemispheres has received considerably less attention. Using dynamic causal modeling (DCM) for fMRI, we analyzed the effective connectivity between the core regions in the face perception network of healthy humans to unveil the mechanisms underlying both intra- and interhemispheric integration. Our results suggest that the right-hemispheric lateralization of the network is due to an asymmetric face-specific interhemispheric recruitment at an early processing stage - that is, at the level of the occipital face area (OFA) but not the fusiform face area (FFA). As a structural correlate, we found that OFA gray matter volume was correlated with this asymmetric interhemispheric recruitment. Furthermore, exploratory analyses revealed that interhemispheric connection asymmetries were correlated with the strength of pupil constriction in response to faces, a measure with potential sensitivity to holistic (as opposed to feature-based) processing of faces. Overall, our findings thus provide a mechanistic description for lateralized processes in the core face perception network, point to a decisive role of interhemispheric integration at an early stage of face processing among bilateral OFA, and tentatively indicate a relation to individual variability in processing strategies for faces. These findings provide a promising avenue for systematic investigations of the potential role of interhemispheric integration in future studies. |
J Freeman; G J Brouwer; D J Heeger; E P Merriam Orientation decoding depends on maps, not columns Journal Article Journal of Neuroscience, 31 (13), pp. 4792–4804, 2011. Abstract | Links | BibTeX @article{Freeman2011,
title = {Orientation decoding depends on maps, not columns},
author = {J Freeman and G J Brouwer and D J Heeger and E P Merriam},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.5160-10.2011},
doi = {10.1523/JNEUROSCI.5160-10.2011},
year = {2011},
date = {2011-01-01},
journal = {Journal of Neuroscience},
volume = {31},
number = {13},
pages = {4792--4804},
abstract = {The representation of orientation in primary visual cortex (V1) has been examined at a fine spatial scale corresponding to the columnar architecture. We present functional magnetic resonance imaging (fMRI) measurements providing evidence for a topographic map of orientation preference in human V1 at a much coarser scale, in register with the angular-position component of the retinotopic map of V1. This coarse-scale orientation map provides a parsimonious explanation for why multivariate pattern analysis methods succeed in decoding stimulus orientation from fMRI measurements, challenging the widely held assumption that decoding results reflect sampling of spatial irregularities in the fine-scale columnar architecture. Decoding stimulus attributes and cognitive states from fMRI measurements has proven useful for a number of applications, but our results demonstrate that the interpretation cannot assume decoding reflects or exploits columnar organization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The representation of orientation in primary visual cortex (V1) has been examined at a fine spatial scale corresponding to the columnar architecture. We present functional magnetic resonance imaging (fMRI) measurements providing evidence for a topographic map of orientation preference in human V1 at a much coarser scale, in register with the angular-position component of the retinotopic map of V1. This coarse-scale orientation map provides a parsimonious explanation for why multivariate pattern analysis methods succeed in decoding stimulus orientation from fMRI measurements, challenging the widely held assumption that decoding results reflect sampling of spatial irregularities in the fine-scale columnar architecture. Decoding stimulus attributes and cognitive states from fMRI measurements has proven useful for a number of applications, but our results demonstrate that the interpretation cannot assume decoding reflects or exploits columnar organization. |
J Freeman; D J Heeger; E P Merriam Coarse-scale biases for spirals and orientation in human visual cortex Journal Article Journal of Neuroscience, 33 (50), pp. 19695–19703, 2013. Abstract | Links | BibTeX @article{Freeman2013,
title = {Coarse-scale biases for spirals and orientation in human visual cortex},
author = {J Freeman and D J Heeger and E P Merriam},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.0889-13.2013},
doi = {10.1523/JNEUROSCI.0889-13.2013},
year = {2013},
date = {2013-01-01},
journal = {Journal of Neuroscience},
volume = {33},
number = {50},
pages = {19695--19703},
abstract = {Multivariate decoding analyses are widely applied to functional magnetic resonance imaging (fMRI) data, but there is controversy over their interpretation. Orientation decoding in primary visual cortex (V1) reflects coarse-scale biases, including an over-representation of radial orientations. But fMRI responses to clockwise and counter-clockwise spirals can also be decoded. Because these stimuli are matched for radial orientation, while differing in local orientation, it has been argued that fine-scale columnar selectivity for orientation contributes to orientation decoding. We measured fMRI responses in human V1 to both oriented gratings and spirals. Responses to oriented gratings exhibited a complex topography, including a radial bias that was most pronounced in the peripheral representation, and a near-vertical bias that was most pronounced near the foveal representation. Responses to clockwise and counter-clockwise spirals also exhibited coarse-scale organization, at the scale of entire visual quadrants. The preference of each voxel for clockwise or counter-clockwise spirals was predicted from the preferences of that voxel for orientation and spatial position (i.e., within the retinotopic map). Our results demonstrate a bias for local stimulus orientation that has a coarse spatial scale, is robust across stimulus classes (spirals and gratings), and suffices to explain decoding from fMRI responses in V1.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Multivariate decoding analyses are widely applied to functional magnetic resonance imaging (fMRI) data, but there is controversy over their interpretation. Orientation decoding in primary visual cortex (V1) reflects coarse-scale biases, including an over-representation of radial orientations. But fMRI responses to clockwise and counter-clockwise spirals can also be decoded. Because these stimuli are matched for radial orientation, while differing in local orientation, it has been argued that fine-scale columnar selectivity for orientation contributes to orientation decoding. We measured fMRI responses in human V1 to both oriented gratings and spirals. Responses to oriented gratings exhibited a complex topography, including a radial bias that was most pronounced in the peripheral representation, and a near-vertical bias that was most pronounced near the foveal representation. Responses to clockwise and counter-clockwise spirals also exhibited coarse-scale organization, at the scale of entire visual quadrants. The preference of each voxel for clockwise or counter-clockwise spirals was predicted from the preferences of that voxel for orientation and spatial position (i.e., within the retinotopic map). Our results demonstrate a bias for local stimulus orientation that has a coarse spatial scale, is robust across stimulus classes (spirals and gratings), and suffices to explain decoding from fMRI responses in V1. |
Marc Galanter; Zoran Josipovic; Helen Dermatis; Jochen Weber; Mary Alice Millard An initial fMRI study on neural correlates of prayer in members of Alcoholics Anonymous Journal Article American Journal of Drug and Alcohol Abuse, 43 (1), pp. 44–54, 2017. Abstract | Links | BibTeX @article{Galanter2017,
title = {An initial fMRI study on neural correlates of prayer in members of Alcoholics Anonymous},
author = {Marc Galanter and Zoran Josipovic and Helen Dermatis and Jochen Weber and Mary Alice Millard},
url = {http://dx.doi.org/10.3109/00952990.2016.1141912},
doi = {10.3109/00952990.2016.1141912},
year = {2017},
date = {2017-01-01},
journal = {American Journal of Drug and Alcohol Abuse},
volume = {43},
number = {1},
pages = {44--54},
publisher = {Informa Healthcare},
abstract = {Background: Many individuals with alcohol-use disorders who had experienced alcohol craving before joining Alcoholics Anonymous (AA) report little or no craving after becoming long-term members. Their use of AA prayers may contribute to this. Neural mechanisms underlying this process have not been delineated. Objective: To define experiential and neural correlates of diminished alcohol craving followingAA prayers amongmembers with long-termabstinence. Methods: Twenty AAmembers with long-term abstinence participated. Self-report measures and functional magnetic resonance imaging of differential neural response to alcohol-craving-inducing images were obtained in three conditions: after reading of AA prayers, after reading irrelevant news, and with passive viewing. Random-effects robust regressions were computed for the main effect (prayer textgreater passive + news) and for estimating the correlations between themain effect and the self-report measures. Results: Compared to the other two conditions, the prayer condition was characterized by: less self-reported craving; increased activation in left-anterior middle frontal gyrus, left superior parietal lobule, bilateral precuneus, and bilateral posterior middle temporal gyrus. Craving following prayer was inversely correlated with activation in brain areas associated with self-referential processing and the default mode network, and with characteristics reflecting AA program involvement. Conclusion:AA members' prayer was asso- ciated with a relative reduction in self-reported craving and with concomitant engagement of neural mechanisms that reflect control of attention and emotion. These findings suggest neural processes underlying the apparent effectiveness of AA prayer.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Many individuals with alcohol-use disorders who had experienced alcohol craving before joining Alcoholics Anonymous (AA) report little or no craving after becoming long-term members. Their use of AA prayers may contribute to this. Neural mechanisms underlying this process have not been delineated. Objective: To define experiential and neural correlates of diminished alcohol craving followingAA prayers amongmembers with long-termabstinence. Methods: Twenty AAmembers with long-term abstinence participated. Self-report measures and functional magnetic resonance imaging of differential neural response to alcohol-craving-inducing images were obtained in three conditions: after reading of AA prayers, after reading irrelevant news, and with passive viewing. Random-effects robust regressions were computed for the main effect (prayer textgreater passive + news) and for estimating the correlations between themain effect and the self-report measures. Results: Compared to the other two conditions, the prayer condition was characterized by: less self-reported craving; increased activation in left-anterior middle frontal gyrus, left superior parietal lobule, bilateral precuneus, and bilateral posterior middle temporal gyrus. Craving following prayer was inversely correlated with activation in brain areas associated with self-referential processing and the default mode network, and with characteristics reflecting AA program involvement. Conclusion:AA members' prayer was asso- ciated with a relative reduction in self-reported craving and with concomitant engagement of neural mechanisms that reflect control of attention and emotion. These findings suggest neural processes underlying the apparent effectiveness of AA prayer. |
Jan Willem de Gee; Olympia Colizoli; Niels A Kloosterman; Tomas Knapen; Sander Nieuwenhuis; Tobias H Donner Dynamic modulation of decision biases by brainstem arousal systems Journal Article eLife, 6 , pp. 1–36, 2017. Abstract | Links | BibTeX @article{Gee2017,
title = {Dynamic modulation of decision biases by brainstem arousal systems},
author = {Jan Willem de Gee and Olympia Colizoli and Niels A Kloosterman and Tomas Knapen and Sander Nieuwenhuis and Tobias H Donner},
url = {https://cdn.elifesciences.org/articles/23232/elife-23232-v3.pdf},
doi = {10.7554/eLife.23232},
year = {2017},
date = {2017-01-01},
journal = {eLife},
volume = {6},
pages = {1--36},
abstract = {Decision-makers often arrive at different choices when faced with repeated presentations of the same evidence. Variability of behavior is commonly attributed to noise in the brain's decision-making machinery. We hypothesized that phasic responses of brainstem arousal systems are a significant source of this variability. We tracked pupil responses (a proxy of phasic arousal) during sensory-motor decisions in humans, across different sensory modalities and task protocols. Large pupil responses generally predicted a reduction in decision bias. Using fMRI, we showed that the pupil-linked bias reduction was (i) accompanied by a modulation of choice-encoding pattern signals in parietal and prefrontal cortex and (ii) predicted by phasic, pupil-linked responses of a number of neuromodulatory brainstem centers involved in the control of cortical arousal state, including the noradrenergic locus coeruleus. We conclude that phasic arousal suppresses decision bias on a trial-by-trial basis, thus accounting for a significant component of the variability of choice behavior.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Decision-makers often arrive at different choices when faced with repeated presentations of the same evidence. Variability of behavior is commonly attributed to noise in the brain's decision-making machinery. We hypothesized that phasic responses of brainstem arousal systems are a significant source of this variability. We tracked pupil responses (a proxy of phasic arousal) during sensory-motor decisions in humans, across different sensory modalities and task protocols. Large pupil responses generally predicted a reduction in decision bias. Using fMRI, we showed that the pupil-linked bias reduction was (i) accompanied by a modulation of choice-encoding pattern signals in parietal and prefrontal cortex and (ii) predicted by phasic, pupil-linked responses of a number of neuromodulatory brainstem centers involved in the control of cortical arousal state, including the noradrenergic locus coeruleus. We conclude that phasic arousal suppresses decision bias on a trial-by-trial basis, thus accounting for a significant component of the variability of choice behavior. |
Hanna Gertz; Maximilian Hilger; Mathias Hegele; Katja Fiehler Violating instructed human agency: An fMRI study on ocular tracking of biological and nonbiological motion stimuli Journal Article NeuroImage, 138 , pp. 109–122, 2016. Abstract | Links | BibTeX @article{Gertz2016,
title = {Violating instructed human agency: An fMRI study on ocular tracking of biological and nonbiological motion stimuli},
author = {Hanna Gertz and Maximilian Hilger and Mathias Hegele and Katja Fiehler},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.05.043},
doi = {10.1016/j.neuroimage.2016.05.043},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {138},
pages = {109--122},
publisher = {Elsevier Inc.},
abstract = {Previous studies have shown that beliefs about the human origin of a stimulus are capable of modulating the coupling of perception and action. Such beliefs can be based on top-down recognition of the identity of an actor or bottom-up observation of the behavior of the stimulus. Instructed human agency has been shown to lead to superior tracking performance of a moving dot as compared to instructed computer agency, especially when the dot followed a biological velocity profile and thus matched the predicted movement, whereas a violation of instructed human agency by a nonbiological dot motion impaired oculomotor tracking (Zwickel et al., 2012). This suggests that the instructed agency biases the selection of predictive models on the movement trajectory of the dot motion. The aim of the present fMRI study was to examine the neural correlates of top-down and bottom-up modulations of perception–action couplings by manipulating the instructed agency (human action vs. computer-generated action) and the observable behavior of the stimulus (biological vs. nonbiological velocity profile). To this end, participants performed an oculomotor tracking task in an MRI environment. Oculomotor tracking activated areas of the eye movement network. A right-hemisphere occipito-temporal cluster comprising the motion-sensitive area V5 showed a preference for the biological as compared to the nonbiological velocity profile. Importantly, a mismatch between instructed human agency and a nonbiological velocity profile primarily activated medial–frontal areas comprising the frontal pole, the paracingulate gyrus, and the anterior cingulate gyrus, as well as the cerebellum and the supplementary eye field as part of the eye movement network. This mismatch effect was specific to the instructed human agency and did not occur in conditions with a mismatch between instructed computer agency and a biological velocity profile. Our results support the hypothesis that humans activate a specific predictive model for biological movements based on their own motor expertise. A violation of this predictive model causes costs as the movement needs to be corrected in accordance with incoming (nonbiological) sensory information.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Previous studies have shown that beliefs about the human origin of a stimulus are capable of modulating the coupling of perception and action. Such beliefs can be based on top-down recognition of the identity of an actor or bottom-up observation of the behavior of the stimulus. Instructed human agency has been shown to lead to superior tracking performance of a moving dot as compared to instructed computer agency, especially when the dot followed a biological velocity profile and thus matched the predicted movement, whereas a violation of instructed human agency by a nonbiological dot motion impaired oculomotor tracking (Zwickel et al., 2012). This suggests that the instructed agency biases the selection of predictive models on the movement trajectory of the dot motion. The aim of the present fMRI study was to examine the neural correlates of top-down and bottom-up modulations of perception–action couplings by manipulating the instructed agency (human action vs. computer-generated action) and the observable behavior of the stimulus (biological vs. nonbiological velocity profile). To this end, participants performed an oculomotor tracking task in an MRI environment. Oculomotor tracking activated areas of the eye movement network. A right-hemisphere occipito-temporal cluster comprising the motion-sensitive area V5 showed a preference for the biological as compared to the nonbiological velocity profile. Importantly, a mismatch between instructed human agency and a nonbiological velocity profile primarily activated medial–frontal areas comprising the frontal pole, the paracingulate gyrus, and the anterior cingulate gyrus, as well as the cerebellum and the supplementary eye field as part of the eye movement network. This mismatch effect was specific to the instructed human agency and did not occur in conditions with a mismatch between instructed computer agency and a biological velocity profile. Our results support the hypothesis that humans activate a specific predictive model for biological movements based on their own motor expertise. A violation of this predictive model causes costs as the movement needs to be corrected in accordance with incoming (nonbiological) sensory information. |
Stephan Geuter; Sabrina Boll; Falk Eippert; Christian Büchel Functional dissociation of stimulus intensity encoding and predictive coding of pain in the insula Journal Article eLife, 6 , pp. 1–22, 2017. Abstract | Links | BibTeX @article{Geuter2017,
title = {Functional dissociation of stimulus intensity encoding and predictive coding of pain in the insula},
author = {Stephan Geuter and Sabrina Boll and Falk Eippert and Christian Büchel},
doi = {10.7554/eLife.24770},
year = {2017},
date = {2017-01-01},
journal = {eLife},
volume = {6},
pages = {1--22},
abstract = {textlessptextgreaterThe computational principles by which the brain creates a painful experience from nociception are still unknown. Classic theories suggest that cortical regions either reflect stimulus intensity or additive effects of intensity and expectations, respectively. By contrast, predictive coding theories provide a unified framework explaining how perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these believes against sensory input. Using functional magnetic resonance imaging during a probabilistic heat pain paradigm, we investigated which computations underlie pain perception. Skin conductance, pupil dilation, and anterior insula responses to cued pain stimuli strictly followed the response patterns hypothesized by the predictive coding model, whereas posterior insula encoded stimulus intensity. This novel functional dissociation of pain processing within the insula together with previously observed alterations in chronic pain offer a novel interpretation of aberrant pain processing as disturbed weighting of predictions and prediction errors.textless/ptextgreater},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
textlessptextgreaterThe computational principles by which the brain creates a painful experience from nociception are still unknown. Classic theories suggest that cortical regions either reflect stimulus intensity or additive effects of intensity and expectations, respectively. By contrast, predictive coding theories provide a unified framework explaining how perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these believes against sensory input. Using functional magnetic resonance imaging during a probabilistic heat pain paradigm, we investigated which computations underlie pain perception. Skin conductance, pupil dilation, and anterior insula responses to cued pain stimuli strictly followed the response patterns hypothesized by the predictive coding model, whereas posterior insula encoded stimulus intensity. This novel functional dissociation of pain processing within the insula together with previously observed alterations in chronic pain offer a novel interpretation of aberrant pain processing as disturbed weighting of predictions and prediction errors.textless/ptextgreater |
Lauren R Godier; Jessica C Scaife; Sven Braeutigam; Rebecca J Park Enhanced early neuronal processing of food pictures in Anorexia Nervosa: A magnetoencephalography study Journal Article Psychiatry Journal, 2016 , pp. 1–13, 2016. Abstract | Links | BibTeX @article{Godier2016,
title = {Enhanced early neuronal processing of food pictures in Anorexia Nervosa: A magnetoencephalography study},
author = {Lauren R Godier and Jessica C Scaife and Sven Braeutigam and Rebecca J Park},
url = {http://www.hindawi.com/journals/psychiatry/2016/1795901/},
doi = {10.1155/2016/1795901},
year = {2016},
date = {2016-01-01},
journal = {Psychiatry Journal},
volume = {2016},
pages = {1--13},
abstract = {Neuroimaging studies in Anorexia Nervosa (AN) have shown increased activation in reward and cognitive control regions in response to food, and a behavioral attentional bias (AB) towards food stimuli is reported. This study aimed to further investigate the neural processing of food using magnetoencephalography (MEG). Participants were 13 females with restricting-type AN, 14 females recovered from restricting-type AN, and 15 female healthy controls. MEG data was acquired whilst participants viewed high- and low-calorie food pictures. Attention was assessed with a reaction time task and eye tracking. Time-series analysis suggested increased neural activity in response to both calorie conditions in the AN groups, consistent with an early AB. Increased activity was observed at 150 ms in the current AN group. Neuronal activity at this latency was at normal level in the recovered group; however, this group exhibited enhanced activity at 320 ms after stimulus. Consistent with previous studies, analysis in source space and behavioral data suggested enhanced attention and cognitive control processes in response to food stimuli in AN. This may enable avoidance of salient food stimuli and maintenance of dietary restraint in AN. A later latency of increased activity in the recovered group may reflect a reversal of this avoidance, with source space and behavioral data indicating increased visual and cognitive processing of food stimuli.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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Neuroimaging studies in Anorexia Nervosa (AN) have shown increased activation in reward and cognitive control regions in response to food, and a behavioral attentional bias (AB) towards food stimuli is reported. This study aimed to further investigate the neural processing of food using magnetoencephalography (MEG). Participants were 13 females with restricting-type AN, 14 females recovered from restricting-type AN, and 15 female healthy controls. MEG data was acquired whilst participants viewed high- and low-calorie food pictures. Attention was assessed with a reaction time task and eye tracking. Time-series analysis suggested increased neural activity in response to both calorie conditions in the AN groups, consistent with an early AB. Increased activity was observed at 150 ms in the current AN group. Neuronal activity at this latency was at normal level in the recovered group; however, this group exhibited enhanced activity at 320 ms after stimulus. Consistent with previous studies, analysis in source space and behavioral data suggested enhanced attention and cognitive control processes in response to food stimuli in AN. This may enable avoidance of salient food stimuli and maintenance of dietary restraint in AN. A later latency of increased activity in the recovered group may reflect a reversal of this avoidance, with source space and behavioral data indicating increased visual and cognitive processing of food stimuli. |
Claudia C Gonzalez; Jac Billington; Melanie R Burke The involvement of the fronto-parietal brain network in oculomotor sequence learning using fMRI Journal Article Neuropsychologia, 87 , pp. 1–11, 2016. Abstract | Links | BibTeX @article{Gonzalez2016,
title = {The involvement of the fronto-parietal brain network in oculomotor sequence learning using fMRI},
author = {Claudia C Gonzalez and Jac Billington and Melanie R Burke},
url = {http://dx.doi.org/10.1016/j.neuropsychologia.2016.04.021},
doi = {10.1016/j.neuropsychologia.2016.04.021},
year = {2016},
date = {2016-01-01},
journal = {Neuropsychologia},
volume = {87},
pages = {1--11},
publisher = {Elsevier},
abstract = {The basis of motor learning involves decomposing complete actions into a series of predictive individual components that form the whole. The present fMRI study investigated the areas of the human brain important for oculomotor short-term learning, by using a novel sequence learning paradigm that is equivalent in visual and temporal properties for both saccades and pursuit, enabling more direct comparisons between the oculomotor subsystems. In contrast with previous studies that have implemented a series of discrete ramps to observe predictive behaviour as evidence for learning, we presented a continuous sequence of interlinked components that better represents sequences of actions. We implemented both a classic univariate fMRI analysis, followed by a further multivariate pattern analysis (MVPA) within a priori regions of interest, to investigate oculomotor sequence learning in the brain and to determine whether these mechanisms overlap in pursuit and saccades as part of a higher order learning network. This study has uniquely identified an equivalent frontal-parietal network (dorsolateral prefrontal cortex, frontal eye fields and posterior parietal cortex) in both saccades and pursuit sequence learning. In addition, this is the first study to investigate oculomotor sequence learning during fMRI brain imaging, and makes significant contributions to understanding the role of the dorsal networks in motor learning.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The basis of motor learning involves decomposing complete actions into a series of predictive individual components that form the whole. The present fMRI study investigated the areas of the human brain important for oculomotor short-term learning, by using a novel sequence learning paradigm that is equivalent in visual and temporal properties for both saccades and pursuit, enabling more direct comparisons between the oculomotor subsystems. In contrast with previous studies that have implemented a series of discrete ramps to observe predictive behaviour as evidence for learning, we presented a continuous sequence of interlinked components that better represents sequences of actions. We implemented both a classic univariate fMRI analysis, followed by a further multivariate pattern analysis (MVPA) within a priori regions of interest, to investigate oculomotor sequence learning in the brain and to determine whether these mechanisms overlap in pursuit and saccades as part of a higher order learning network. This study has uniquely identified an equivalent frontal-parietal network (dorsolateral prefrontal cortex, frontal eye fields and posterior parietal cortex) in both saccades and pursuit sequence learning. In addition, this is the first study to investigate oculomotor sequence learning during fMRI brain imaging, and makes significant contributions to understanding the role of the dorsal networks in motor learning. |
Evan M Gordon; Timothy O Laumann; Adrian W Gilmore; Dillan J Newbold; Deanna J Greene; Jeffrey J Berg; Mario Ortega; Catherine Hoyt-Drazen; Caterina Gratton; Haoxin Sun; Jacqueline M Hampton; Rebecca S Coalson; Annie L Nguyen; Kathleen B McDermott; Joshua S Shimony; Abraham Z Snyder; Bradley L Schlaggar; Steven E Petersen; Steven M Nelson; Nico U F Dosenbach Precision functional mapping of individual human brains Journal Article Neuron, 95 (4), pp. 791–807, 2017. Abstract | Links | BibTeX @article{Gordon2017,
title = {Precision functional mapping of individual human brains},
author = {Evan M Gordon and Timothy O Laumann and Adrian W Gilmore and Dillan J Newbold and Deanna J Greene and Jeffrey J Berg and Mario Ortega and Catherine Hoyt-Drazen and Caterina Gratton and Haoxin Sun and Jacqueline M Hampton and Rebecca S Coalson and Annie L Nguyen and Kathleen B McDermott and Joshua S Shimony and Abraham Z Snyder and Bradley L Schlaggar and Steven E Petersen and Steven M Nelson and Nico U F Dosenbach},
url = {http://dx.doi.org/10.1016/j.neuron.2017.07.011},
doi = {10.1016/j.neuron.2017.07.011},
year = {2017},
date = {2017-01-01},
journal = {Neuron},
volume = {95},
number = {4},
pages = {791--807},
publisher = {Elsevier Inc.},
abstract = {Human functional MRI (fMRI) research primarily focuses on analyzing data averaged across groups, which limits the detail, specificity, and clinical utility of fMRI resting-state functional connectivity (RSFC) and task-activation maps. To push our understanding of functional brain organization to the level of individual humans, we assembled a novel MRI dataset containing 5 hr of RSFC data, 6 hr of task fMRI, multiple structural MRIs, and neuro- psychological tests from each of ten adults. Using these data, we generated ten high-fidelity, individual-specific functional connectomes. This individual-connectome approach revealed several new types of spatial and organizational variability in brain networks, including unique network features and topologies that corresponded with structural and task-derived brain features. We are releasing this highly sampled, individual-focused dataset as a resource for neuroscientists, and we propose precision individual connectomics as a model for future work examining the organization of healthy and diseased individual human brains.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Human functional MRI (fMRI) research primarily focuses on analyzing data averaged across groups, which limits the detail, specificity, and clinical utility of fMRI resting-state functional connectivity (RSFC) and task-activation maps. To push our understanding of functional brain organization to the level of individual humans, we assembled a novel MRI dataset containing 5 hr of RSFC data, 6 hr of task fMRI, multiple structural MRIs, and neuro- psychological tests from each of ten adults. Using these data, we generated ten high-fidelity, individual-specific functional connectomes. This individual-connectome approach revealed several new types of spatial and organizational variability in brain networks, including unique network features and topologies that corresponded with structural and task-derived brain features. We are releasing this highly sampled, individual-focused dataset as a resource for neuroscientists, and we propose precision individual connectomics as a model for future work examining the organization of healthy and diseased individual human brains. |
Tsafrir Greenberg; Joshua M Carlson; Jiook Cha; Greg Hajcak; Lilianne R Mujica-Parodi Ventromedial prefrontal cortex reactivity is altered in generalized anxiety disorder during fear generalization Journal Article Depression and Anxiety, 30 (3), pp. 242–250, 2013. Abstract | Links | BibTeX @article{Greenberg2013,
title = {Ventromedial prefrontal cortex reactivity is altered in generalized anxiety disorder during fear generalization},
author = {Tsafrir Greenberg and Joshua M Carlson and Jiook Cha and Greg Hajcak and Lilianne R Mujica-Parodi},
url = {http://doi.wiley.com/10.1002/da.22016},
doi = {10.1002/da.22016},
year = {2013},
date = {2013-01-01},
journal = {Depression and Anxiety},
volume = {30},
number = {3},
pages = {242--250},
abstract = {BACKGROUND: Fear generalization is thought to contribute to the development and maintenance of anxiety symptoms and accordingly has been the focus of recent research. Previously, we reported that in healthy individuals (N = 25) neural reactivity in the insula, anterior cingulate cortex (ACC), supplementary motor area (SMA), and caudate follow a generalization gradient with a peak response to a conditioned stimulus (CS) that declines with greater perceptual dissimilarity of generalization stimuli (GS) to the CS. In contrast, reactivity in the ventromedial prefrontal cortex (vmPFC), a region linked to fear inhibition, showed an opposite response pattern. The aim of the current study was to examine whether neural responses to fear generalization differ in generalized anxiety disorder (GAD). A second aim was to examine connectivity of primary regions engaged by the generalization task in the GAD group versus healthy group, using psychophysiological interaction analysis. METHODS: Thirty-two women diagnosed with GAD were scanned using the same generalization task as our healthy group. RESULTS: Individuals with GAD exhibited a less discriminant vmPFC response pattern suggestive of deficient recruitment of vmPFC during fear inhibition. Across participants, there was enhanced anterior insula (aINS) coupling with the posterior insula, ACC, SMA, and amygdala during presentation of the CS, consistent with a modulatory role for the aINS in the execution of fear responses. CONCLUSIONS: These findings suggest that deficits in fear regulation, rather than in the excitatory response itself, are more critical to the pathophysiology of GAD in the context of fear generalization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
BACKGROUND: Fear generalization is thought to contribute to the development and maintenance of anxiety symptoms and accordingly has been the focus of recent research. Previously, we reported that in healthy individuals (N = 25) neural reactivity in the insula, anterior cingulate cortex (ACC), supplementary motor area (SMA), and caudate follow a generalization gradient with a peak response to a conditioned stimulus (CS) that declines with greater perceptual dissimilarity of generalization stimuli (GS) to the CS. In contrast, reactivity in the ventromedial prefrontal cortex (vmPFC), a region linked to fear inhibition, showed an opposite response pattern. The aim of the current study was to examine whether neural responses to fear generalization differ in generalized anxiety disorder (GAD). A second aim was to examine connectivity of primary regions engaged by the generalization task in the GAD group versus healthy group, using psychophysiological interaction analysis. METHODS: Thirty-two women diagnosed with GAD were scanned using the same generalization task as our healthy group. RESULTS: Individuals with GAD exhibited a less discriminant vmPFC response pattern suggestive of deficient recruitment of vmPFC during fear inhibition. Across participants, there was enhanced anterior insula (aINS) coupling with the posterior insula, ACC, SMA, and amygdala during presentation of the CS, consistent with a modulatory role for the aINS in the execution of fear responses. CONCLUSIONS: These findings suggest that deficits in fear regulation, rather than in the excitatory response itself, are more critical to the pathophysiology of GAD in the context of fear generalization. |
Tsafrir Greenberg; Joshua M Carlson; Jiook Cha; Greg Hajcak; Lilianne R Mujica-Parodi Neural reactivity tracks fear generalization gradients Journal Article Biological Psychology, 92 (1), pp. 2–8, 2013. Abstract | Links | BibTeX @article{Greenberg2013a,
title = {Neural reactivity tracks fear generalization gradients},
author = {Tsafrir Greenberg and Joshua M Carlson and Jiook Cha and Greg Hajcak and Lilianne R Mujica-Parodi},
url = {http://dx.doi.org/10.1016/j.biopsycho.2011.12.007},
doi = {10.1016/j.biopsycho.2011.12.007},
year = {2013},
date = {2013-01-01},
journal = {Biological Psychology},
volume = {92},
number = {1},
pages = {2--8},
publisher = {Elsevier B.V.},
abstract = {Recent studies on fear generalization have demonstrated that fear-potentiated startle and skin conductance responses to a conditioned stimulus (CS) generalize to similar stimuli, with the strength of the fear response linked to perceptual similarity to the CS. The aim of the present study was to extend this work by examining neural correlates of fear generalization. An initial experiment (N= 8) revealed that insula reactivity tracks the conditioned fear gradient. We then replicated this effect in a larger independent sample (N= 25). Activation in the insula, anterior cingulate, right supplementary motor cortex and caudate increased reactivity as generalization stimuli (GS) were more similar to the CS, consistent with participants' overall ratings of perceived shock likelihood and pupillary response to each stimulus.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Recent studies on fear generalization have demonstrated that fear-potentiated startle and skin conductance responses to a conditioned stimulus (CS) generalize to similar stimuli, with the strength of the fear response linked to perceptual similarity to the CS. The aim of the present study was to extend this work by examining neural correlates of fear generalization. An initial experiment (N= 8) revealed that insula reactivity tracks the conditioned fear gradient. We then replicated this effect in a larger independent sample (N= 25). Activation in the insula, anterior cingulate, right supplementary motor cortex and caudate increased reactivity as generalization stimuli (GS) were more similar to the CS, consistent with participants' overall ratings of perceived shock likelihood and pupillary response to each stimulus. |
Sarah Gregory; Marco Fusca; Geraint Rees; Samuel D Schwarzkopf; Gareth Barnes Gamma frequency and the spatial tuning of primary visual cortex Journal Article PLoS ONE, 11 (6), pp. 1–12, 2016. Abstract | Links | BibTeX @article{Gregory2016a,
title = {Gamma frequency and the spatial tuning of primary visual cortex},
author = {Sarah Gregory and Marco Fusca and Geraint Rees and Samuel D Schwarzkopf and Gareth Barnes},
doi = {10.1371/journal.pone.0157374},
year = {2016},
date = {2016-01-01},
journal = {PLoS ONE},
volume = {11},
number = {6},
pages = {1--12},
abstract = {Visual stimulation produces oscillatory gamma responses in human primary visual cortex (V1) that also relate to visual perception. We have shown previously that peak gamma frequency positively correlates with central V1 cortical surface area. We hypothesized that people with larger V1 would have smaller receptive fields and that receptive field size, not V1 are, might explain this relationship. Here we set out to test this hypothesis directly by investigating the relationship between fMRI estimated population receptive field (pRF) size and gamma frequency in V1. We stimulated both the near-centre and periphery of the visual field using both large and small stimuli in each location and replicated our previous finding of a positive correlation between V1 surface area and peak gamma frequency. Counter to our expectation, we found that between participants V1 size (and not pRF size) accounted for most of the variability in gamma frequency. Within-participants we found that gamma frequency increased, rather than decreased, with stimulus eccentricity directly contradicting our initial hypothesis.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Visual stimulation produces oscillatory gamma responses in human primary visual cortex (V1) that also relate to visual perception. We have shown previously that peak gamma frequency positively correlates with central V1 cortical surface area. We hypothesized that people with larger V1 would have smaller receptive fields and that receptive field size, not V1 are, might explain this relationship. Here we set out to test this hypothesis directly by investigating the relationship between fMRI estimated population receptive field (pRF) size and gamma frequency in V1. We stimulated both the near-centre and periphery of the visual field using both large and small stimuli in each location and replicated our previous finding of a positive correlation between V1 surface area and peak gamma frequency. Counter to our expectation, we found that between participants V1 size (and not pRF size) accounted for most of the variability in gamma frequency. Within-participants we found that gamma frequency increased, rather than decreased, with stimulus eccentricity directly contradicting our initial hypothesis. |
Joseph C Griffis; Abdurahman S Elkhetali; Ryan J Vaden; Kristina M Visscher Distinct effects of trial-driven and task set-related control in primary visual cortex Journal Article NeuroImage, 120 , pp. 285–297, 2015. Abstract | Links | BibTeX @article{Griffis2015,
title = {Distinct effects of trial-driven and task set-related control in primary visual cortex},
author = {Joseph C Griffis and Abdurahman S Elkhetali and Ryan J Vaden and Kristina M Visscher},
doi = {10.1007/s10995-015-1800-4.Alcohol},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage},
volume = {120},
pages = {285--297},
abstract = {Task sets are task-specific configurations of cognitive processes that facilitate task-appropriate reactions to stimuli. While it is established that the trial-by-trial deployment of visual attention to expected stimuli influences neural responses in primary visual cortex (V1) in a retinotopically specific manner, it is not clear whether the mechanisms that help maintain a task set over many trials also operate with similar retinotopic specificity. Here, we address this question by using BOLD fMRI to characterize how portions of V1 that are specialized for different eccentricities respond during distinct components of an attention-demanding discrimination task: cue-driven preparation for a trial, trial-driven processing, task-initiation at the beginning of a block of trials, and task-maintenance throughout a block of trials. Tasks required either unimodal attention to an auditory or a visual stimulus or selective intermodal attention to the visual or auditory component of simultaneously presented visual and auditory stimuli. We found that while the retinotopic patterns of trial-driven and cue-driven activity depended on the attended stimulus, the retinotopic patterns of task-initiation and task-maintenance activity did not. Further, only the retinotopic patterns of trial-driven activity were found to depend on the presence of inter-modal distraction. Participants who performed well on the intermodal selective attention tasks showed strong task-specific modulations of both trial-driven and task-maintenance activity. Importantly, task-related modulations of trial-driven and task-maintenance activity were in opposite directions. Together, these results confirm that there are (at least) two different processes for top-down control of V1: One, working trial-by-trial, differently modulates activity across different eccentricity sectors - portions of V1 corresponding to different visual eccentricities. The second process works across longer epochs of task performance, and does not differ among eccentricity sectors. These results are discussed in the context of previous literature examining top-down control of visual cortical areas.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Task sets are task-specific configurations of cognitive processes that facilitate task-appropriate reactions to stimuli. While it is established that the trial-by-trial deployment of visual attention to expected stimuli influences neural responses in primary visual cortex (V1) in a retinotopically specific manner, it is not clear whether the mechanisms that help maintain a task set over many trials also operate with similar retinotopic specificity. Here, we address this question by using BOLD fMRI to characterize how portions of V1 that are specialized for different eccentricities respond during distinct components of an attention-demanding discrimination task: cue-driven preparation for a trial, trial-driven processing, task-initiation at the beginning of a block of trials, and task-maintenance throughout a block of trials. Tasks required either unimodal attention to an auditory or a visual stimulus or selective intermodal attention to the visual or auditory component of simultaneously presented visual and auditory stimuli. We found that while the retinotopic patterns of trial-driven and cue-driven activity depended on the attended stimulus, the retinotopic patterns of task-initiation and task-maintenance activity did not. Further, only the retinotopic patterns of trial-driven activity were found to depend on the presence of inter-modal distraction. Participants who performed well on the intermodal selective attention tasks showed strong task-specific modulations of both trial-driven and task-maintenance activity. Importantly, task-related modulations of trial-driven and task-maintenance activity were in opposite directions. Together, these results confirm that there are (at least) two different processes for top-down control of V1: One, working trial-by-trial, differently modulates activity across different eccentricity sectors - portions of V1 corresponding to different visual eccentricities. The second process works across longer epochs of task performance, and does not differ among eccentricity sectors. These results are discussed in the context of previous literature examining top-down control of visual cortical areas. |
Joseph C Griffis; Abdurahman S Elkhetali; Wesley K Burge; Richard H Chen; Anthony D Bowman; Jerzy P Szaflarski; Kristina M Visscher Retinotopic patterns of functional connectivity between V1 and large-scale brain networks during resting fixation Journal Article NeuroImage, 146 , pp. 1071–1083, 2017. Abstract | Links | BibTeX @article{Griffis2017,
title = {Retinotopic patterns of functional connectivity between V1 and large-scale brain networks during resting fixation},
author = {Joseph C Griffis and Abdurahman S Elkhetali and Wesley K Burge and Richard H Chen and Anthony D Bowman and Jerzy P Szaflarski and Kristina M Visscher},
doi = {10.1016/j.neuroimage.2016.08.035},
year = {2017},
date = {2017-01-01},
journal = {NeuroImage},
volume = {146},
pages = {1071--1083},
abstract = {Psychophysical and neurobiological evidence suggests that central and peripheral vision are specialized for different functions. This specialization of function might be expected to lead to differences in the large-scale functional interactions of early cortical areas that represent central and peripheral visual space. Here, we characterize differences in whole-brain functional connectivity among sectors in primary visual cortex (V1) corresponding to central, near-peripheral, and far-peripheral vision during resting fixation. Importantly, our analyses reveal that eccentricity sectors in V1 have different functional connectivity with non-visual areas associated with large-scale brain networks. Regions associated with the fronto-parietal control network are most strongly connected with central sectors of V1, regions associated with the cingulo-opercular control network are most strongly connected with near-peripheral sectors of V1, and regions associated with the default mode and auditory networks are most strongly connected with far-peripheral sectors of V1. Additional analyses suggest that similar patterns are present during eyes-closed rest. These results suggest that different types of visual information may be prioritized by large-scale brain networks with distinct functional profiles, and provide insights into how the small-scale functional specialization within early visual regions such as V1 relates to the large-scale organization of functionally distinct whole-brain networks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Psychophysical and neurobiological evidence suggests that central and peripheral vision are specialized for different functions. This specialization of function might be expected to lead to differences in the large-scale functional interactions of early cortical areas that represent central and peripheral visual space. Here, we characterize differences in whole-brain functional connectivity among sectors in primary visual cortex (V1) corresponding to central, near-peripheral, and far-peripheral vision during resting fixation. Importantly, our analyses reveal that eccentricity sectors in V1 have different functional connectivity with non-visual areas associated with large-scale brain networks. Regions associated with the fronto-parietal control network are most strongly connected with central sectors of V1, regions associated with the cingulo-opercular control network are most strongly connected with near-peripheral sectors of V1, and regions associated with the default mode and auditory networks are most strongly connected with far-peripheral sectors of V1. Additional analyses suggest that similar patterns are present during eyes-closed rest. These results suggest that different types of visual information may be prioritized by large-scale brain networks with distinct functional profiles, and provide insights into how the small-scale functional specialization within early visual regions such as V1 relates to the large-scale organization of functionally distinct whole-brain networks. |
Scott A Guerin; Clifford A Robbins; Adrian W Gilmore; Daniel L Schacter Retrieval failure contributes to gist-based false recognition Journal Article Journal of Memory and Language, 66 (1), pp. 68–78, 2012. Abstract | Links | BibTeX @article{Guerin2012,
title = {Retrieval failure contributes to gist-based false recognition},
author = {Scott A Guerin and Clifford A Robbins and Adrian W Gilmore and Daniel L Schacter},
url = {http://dx.doi.org/10.1016/j.jml.2011.07.002},
doi = {10.1016/j.jml.2011.07.002},
year = {2012},
date = {2012-01-01},
journal = {Journal of Memory and Language},
volume = {66},
number = {1},
pages = {68--78},
publisher = {Elsevier Inc.},
abstract = {People often falsely recognize items that are similar to previously encountered items. This robust memory error is referred to as gist-based false recognition. A widely held view is that this error occurs because the details fade rapidly from our memory. Contrary to this view, an initial experiment revealed that, following the same encoding conditions that produce high rates of gist-based false recognition, participants overwhelmingly chose the correct target rather than its related foil when given the option to do so. A second experiment showed that this result is due to increased access to stored details provided by reinstatement of the originally encoded photograph, rather than to increased attention to the details. Collectively, these results suggest that details needed for accurate recognition are, to a large extent, still stored in memory and that a critical factor determining whether false recognition will occur is whether these details can be accessed during retrieval.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
People often falsely recognize items that are similar to previously encountered items. This robust memory error is referred to as gist-based false recognition. A widely held view is that this error occurs because the details fade rapidly from our memory. Contrary to this view, an initial experiment revealed that, following the same encoding conditions that produce high rates of gist-based false recognition, participants overwhelmingly chose the correct target rather than its related foil when given the option to do so. A second experiment showed that this result is due to increased access to stored details provided by reinstatement of the originally encoded photograph, rather than to increased attention to the details. Collectively, these results suggest that details needed for accurate recognition are, to a large extent, still stored in memory and that a critical factor determining whether false recognition will occur is whether these details can be accessed during retrieval. |
M Guitart-Masip; G R Barnes; A Horner; Markus Bauer; R J Dolan; E Duzel Synchronization of medial temporal lobe and prefrontal rhythms in human decision making Journal Article Journal of Neuroscience, 33 (2), pp. 442–451, 2013. Abstract | Links | BibTeX @article{Guitart-Masip2013,
title = {Synchronization of medial temporal lobe and prefrontal rhythms in human decision making},
author = {M Guitart-Masip and G R Barnes and A Horner and Markus Bauer and R J Dolan and E Duzel},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.2573-12.2013},
doi = {10.1523/JNEUROSCI.2573-12.2013},
year = {2013},
date = {2013-01-01},
journal = {Journal of Neuroscience},
volume = {33},
number = {2},
pages = {442--451},
abstract = {Optimal decision making requires that we integrate mnemonic information regarding previous decisions with value signals that entail likely rewards and punishments. The fact that memory and value signals appear to be coded by segregated brain regions, the hippocampus in the case of memory and sectors of prefrontal cortex in the case of value, raises the question as to how they are integrated during human decision making. Using magnetoencephalography to study healthy human participants, we show increased theta oscillations over frontal and temporal sensors during nonspatial decisions based on memories from previous trials. Using source reconstruction we found that the medial temporal lobe (MTL), in a location compatible with the anterior hippocampus, and the anterior cingulate cortex in the medial wall of the frontal lobe are the source of this increased theta power. Moreover, we observed a correlation between theta power in the MTL source and behavioral performance in decision making, supporting a role for MTL theta oscillations in decision-making performance. These MTL theta oscillations were synchronized with several prefrontal sources, including lateral superior frontal gyrus, dorsal anterior cingulate gyrus, and medial frontopolar cortex. There was no relationship between the strength of synchronization and the expected value of choices. Our results indicate a mnemonic guidance of human decision making, beyond anticipation of expected reward, is supported by hippocampal-prefrontal theta synchronization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Optimal decision making requires that we integrate mnemonic information regarding previous decisions with value signals that entail likely rewards and punishments. The fact that memory and value signals appear to be coded by segregated brain regions, the hippocampus in the case of memory and sectors of prefrontal cortex in the case of value, raises the question as to how they are integrated during human decision making. Using magnetoencephalography to study healthy human participants, we show increased theta oscillations over frontal and temporal sensors during nonspatial decisions based on memories from previous trials. Using source reconstruction we found that the medial temporal lobe (MTL), in a location compatible with the anterior hippocampus, and the anterior cingulate cortex in the medial wall of the frontal lobe are the source of this increased theta power. Moreover, we observed a correlation between theta power in the MTL source and behavioral performance in decision making, supporting a role for MTL theta oscillations in decision-making performance. These MTL theta oscillations were synchronized with several prefrontal sources, including lateral superior frontal gyrus, dorsal anterior cingulate gyrus, and medial frontopolar cortex. There was no relationship between the strength of synchronization and the expected value of choices. Our results indicate a mnemonic guidance of human decision making, beyond anticipation of expected reward, is supported by hippocampal-prefrontal theta synchronization. |
Fei Guo; Tim J Preston; Koel Das; Barry Giesbrecht; Miguel P Eckstein Feature-independent neural coding of target detection during search of natural scenes Journal Article Journal of Neuroscience, 32 (28), pp. 9499–9510, 2012. Abstract | Links | BibTeX @article{Guo2012,
title = {Feature-independent neural coding of target detection during search of natural scenes},
author = {Fei Guo and Tim J Preston and Koel Das and Barry Giesbrecht and Miguel P Eckstein},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.5876-11.2012},
doi = {10.1523/JNEUROSCI.5876-11.2012},
year = {2012},
date = {2012-01-01},
journal = {Journal of Neuroscience},
volume = {32},
number = {28},
pages = {9499--9510},
abstract = {Visual search requires humans to detect a great variety of target objects in scenes cluttered by other objects or the natural environment. It is unknown whether there is a general purpose neural detection mechanism in the brain that codes the presence of a wide variety of categories of objects embedded in natural scenes. We provide evidence for a feature-independent coding mechanism for detecting behaviorally relevant targets in natural scenes in the dorsal frontoparietal network. Pattern classifiers using single-trial fMRI responses in the dorsal frontoparietal network reliably predicted the presence of 368 different target objects and also the observer's choices. Other vision-related areas such as the primary visual cortex, lateral occipital complex, the parahippocampal, and the fusiform gyri did not predict target presence, while high-level association areas related to general purpose decision making, including the dorsolateral prefrontal cortex and anterior cingulate, did. Activity in the intraparietal sulcus, a main area in the dorsal frontoparietal network, correlated with observers' decision confidence and with the task difficulty of individual images. These results cannot be explained by physical differences across images or eye movements. Thus, the dorsal frontoparietal network detects behaviorally relevant targets in natural scenes independent of their defining visual features and may be the human analog of the priority map in monkey lateral intraparietal cortex.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Visual search requires humans to detect a great variety of target objects in scenes cluttered by other objects or the natural environment. It is unknown whether there is a general purpose neural detection mechanism in the brain that codes the presence of a wide variety of categories of objects embedded in natural scenes. We provide evidence for a feature-independent coding mechanism for detecting behaviorally relevant targets in natural scenes in the dorsal frontoparietal network. Pattern classifiers using single-trial fMRI responses in the dorsal frontoparietal network reliably predicted the presence of 368 different target objects and also the observer's choices. Other vision-related areas such as the primary visual cortex, lateral occipital complex, the parahippocampal, and the fusiform gyri did not predict target presence, while high-level association areas related to general purpose decision making, including the dorsolateral prefrontal cortex and anterior cingulate, did. Activity in the intraparietal sulcus, a main area in the dorsal frontoparietal network, correlated with observers' decision confidence and with the task difficulty of individual images. These results cannot be explained by physical differences across images or eye movements. Thus, the dorsal frontoparietal network detects behaviorally relevant targets in natural scenes independent of their defining visual features and may be the human analog of the priority map in monkey lateral intraparietal cortex. |
Michael Hanke; Nico Adelhöfer; Daniel Kottke; Vittorio Iacovella; Ayan Sengupta; Falko R Kaule; Roland Nigbur; Alexander Q Waite; Florian Baumgartner; Jörg Stadler A studyforrest extension, simultaneous fMRI and eye gaze recordings during prolonged natural stimulation Journal Article Scientific Data, 3 , pp. 1–15, 2016. Abstract | Links | BibTeX @article{Hanke2016,
title = {A studyforrest extension, simultaneous fMRI and eye gaze recordings during prolonged natural stimulation},
author = {Michael Hanke and Nico Adelhöfer and Daniel Kottke and Vittorio Iacovella and Ayan Sengupta and Falko R Kaule and Roland Nigbur and Alexander Q Waite and Florian Baumgartner and Jörg Stadler},
doi = {10.1038/sdata.2016.92},
year = {2016},
date = {2016-01-01},
journal = {Scientific Data},
volume = {3},
pages = {1--15},
abstract = {Here we present an update of the studyforrest (http://studyforrest.org) dataset that complements the previously released functional magnetic resonance imaging (fMRI) data for natural language processing with a new two-hour 3 Tesla fMRI acquisition while 15 of the original participants were shown an audio-visual version of the stimulus motion picture. We demonstrate with two validation analyses that these new data support modeling specific properties of the complex natural stimulus, as well as a substantial within-subject BOLD response congruency in brain areas related to the processing of auditory inputs, speech, and narrative when compared to the existing fMRI data for audio-only stimulation. In addition, we provide participants' eye gaze location as recorded simultaneously with fMRI, and an additional sample of 15 control participants whose eye gaze trajectories for the entire movie were recorded in a lab setting-to enable studies on attentional processes and comparative investigations on the potential impact of the stimulation setting on these processes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Here we present an update of the studyforrest (http://studyforrest.org) dataset that complements the previously released functional magnetic resonance imaging (fMRI) data for natural language processing with a new two-hour 3 Tesla fMRI acquisition while 15 of the original participants were shown an audio-visual version of the stimulus motion picture. We demonstrate with two validation analyses that these new data support modeling specific properties of the complex natural stimulus, as well as a substantial within-subject BOLD response congruency in brain areas related to the processing of auditory inputs, speech, and narrative when compared to the existing fMRI data for audio-only stimulation. In addition, we provide participants' eye gaze location as recorded simultaneously with fMRI, and an additional sample of 15 control participants whose eye gaze trajectories for the entire movie were recorded in a lab setting-to enable studies on attentional processes and comparative investigations on the potential impact of the stimulation setting on these processes. |
Wei He; Jon Brock; Blake W Johnson Face-sensitive brain responses measured from a four-year-old child with a custom-sized child MEG system Journal Article Journal of Neuroscience Methods, 222 , pp. 213–217, 2014. Abstract | Links | BibTeX @article{He2014c,
title = {Face-sensitive brain responses measured from a four-year-old child with a custom-sized child MEG system},
author = {Wei He and Jon Brock and Blake W Johnson},
doi = {10.1016/j.jneumeth.2013.11.020},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neuroscience Methods},
volume = {222},
pages = {213--217},
publisher = {222},
abstract = {Background: Previous magnetoencephalography (MEG) studies have failed to find a facesensitive, brain response-M170 in children. If this is the case, this suggests that the developmental trajectory of the M170 is different from that of its electrical equivalent, the N170. We investigated the alternative possibility that the child M170 may not be detectable in conventional adult-sized MEG systems. New method: Brain responses to pictures of faces and well controlled stimuli were measured from the same four-year-old child with a custom child MEG system and an adult-sized MEG system. Results: The goodness of fit of the child's head was about the same over the occipital head surface in both systems, but was much worse over all other parts of the head surface in the adult MEG system compared to the child MEG system. The face-sensitive M170 was measured from the child in both MEG systems, but was larger in amplitude, clearer in morphology, and had a more accurate source localization when measured in the child MEG system. Comparison with existing method: The custom-sized child MEG system is superior for measuring the face-sensitive M170 brain response in children than the conventional adult MEG system. Conclusions: The present results show that the face-sensitive M170 brain response can be elicited in a four-year-old child. This provides new evidence for early maturation of face processing brain mechanisms in humans, and offers new opportunities for the study of neurodevelopmental disorders that show atypical face processing capabilities, such as autism spectrum disorder.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Previous magnetoencephalography (MEG) studies have failed to find a facesensitive, brain response-M170 in children. If this is the case, this suggests that the developmental trajectory of the M170 is different from that of its electrical equivalent, the N170. We investigated the alternative possibility that the child M170 may not be detectable in conventional adult-sized MEG systems. New method: Brain responses to pictures of faces and well controlled stimuli were measured from the same four-year-old child with a custom child MEG system and an adult-sized MEG system. Results: The goodness of fit of the child's head was about the same over the occipital head surface in both systems, but was much worse over all other parts of the head surface in the adult MEG system compared to the child MEG system. The face-sensitive M170 was measured from the child in both MEG systems, but was larger in amplitude, clearer in morphology, and had a more accurate source localization when measured in the child MEG system. Comparison with existing method: The custom-sized child MEG system is superior for measuring the face-sensitive M170 brain response in children than the conventional adult MEG system. Conclusions: The present results show that the face-sensitive M170 brain response can be elicited in a four-year-old child. This provides new evidence for early maturation of face processing brain mechanisms in humans, and offers new opportunities for the study of neurodevelopmental disorders that show atypical face processing capabilities, such as autism spectrum disorder. |
Wei He; Jon Brock; Blake W Johnson Face processing in the brains of pre-school aged children measured with MEG Journal Article NeuroImage, 106 , pp. 317–327, 2015. Abstract | Links | BibTeX @article{He2015a,
title = {Face processing in the brains of pre-school aged children measured with MEG},
author = {Wei He and Jon Brock and Blake W Johnson},
url = {http://dx.doi.org/10.1016/j.neuroimage.2014.11.029},
doi = {10.1016/j.neuroimage.2014.11.029},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage},
volume = {106},
pages = {317--327},
publisher = {Elsevier Inc.},
abstract = {There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions. |
Wei He; Marta I Garrido; Paul F Sowman; Jon Brock; Blake W Johnson Development of effective connectivity in the core network for face perception Journal Article Human Brain Mapping, 36 (6), pp. 2161–2173, 2015. Abstract | Links | BibTeX @article{He2015b,
title = {Development of effective connectivity in the core network for face perception},
author = {Wei He and Marta I Garrido and Paul F Sowman and Jon Brock and Blake W Johnson},
doi = {10.1002/hbm.22762},
year = {2015},
date = {2015-01-01},
journal = {Human Brain Mapping},
volume = {36},
number = {6},
pages = {2161--2173},
abstract = {This study measured effective connectivity within the core face network in young children using a paediatric magnetoencephalograph (MEG). Dynamic casual modeling (DCM) of brain responses was performed in a group of adults (N = 14) and a group of young children aged from 3 to 6 years (N = 15). Three candidate DCM models were tested, and the fits of the MEG data to the three models were compared at both individual and group levels. The results show that the connectivity structure of the core face network differs significantly between adults and children. Further, the relative strengths of face network connections were differentially modulated by experimental conditions in the two groups. These results support the interpretation that the core face network undergoes significant structural configuration and functional specialization between four years of age and adulthood.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This study measured effective connectivity within the core face network in young children using a paediatric magnetoencephalograph (MEG). Dynamic casual modeling (DCM) of brain responses was performed in a group of adults (N = 14) and a group of young children aged from 3 to 6 years (N = 15). Three candidate DCM models were tested, and the fits of the MEG data to the three models were compared at both individual and group levels. The results show that the connectivity structure of the core face network differs significantly between adults and children. Further, the relative strengths of face network connections were differentially modulated by experimental conditions in the two groups. These results support the interpretation that the core face network undergoes significant structural configuration and functional specialization between four years of age and adulthood. |
Simone G Heideman; Freek van Ede; Anna C Nobre Temporal alignment of anticipatory motor cortical beta lateralisation in hidden visual-motor sequences Journal Article European Journal of Neuroscience, 48 (8), pp. 2684–2695, 2018. Abstract | Links | BibTeX @article{Heideman2018,
title = {Temporal alignment of anticipatory motor cortical beta lateralisation in hidden visual-motor sequences},
author = {Simone G Heideman and Freek van Ede and Anna C Nobre},
doi = {10.1111/ejn.13700},
year = {2018},
date = {2018-01-01},
journal = {European Journal of Neuroscience},
volume = {48},
number = {8},
pages = {2684--2695},
abstract = {Performance improves when participants respond to events that are structured in repeating sequences, suggesting that learning can lead to proactive anticipatory preparation. Whereas most sequence-learning studies have emphasised spatial structure, most sequences also contain a prominent temporal structure. We used MEG to investigate spatial and temporal anticipatory neural dynamics in a modified serial reaction time (SRT) task. Performance and brain activity were compared between blocks with learned spatial-temporal sequences and blocks with new sequences. After confirming a strong behavioural benefit of spatial-temporal predictability, we show lateralisation of beta oscillations in anticipation of the response associated with the upcoming target location and show that this also aligns to the expected timing of these forthcoming events. This effect was found both when comparing between repeated (learned) and new (unlearned) sequences, as well as when comparing targets that were expected after short vs. long intervals within the repeated (learned) sequence. Our findings suggest that learning of spatial-temporal structure leads to proactive and dynamic modulation of motor cortical excitability in anticipation of both the location and timing of events that are relevant to guide action.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Performance improves when participants respond to events that are structured in repeating sequences, suggesting that learning can lead to proactive anticipatory preparation. Whereas most sequence-learning studies have emphasised spatial structure, most sequences also contain a prominent temporal structure. We used MEG to investigate spatial and temporal anticipatory neural dynamics in a modified serial reaction time (SRT) task. Performance and brain activity were compared between blocks with learned spatial-temporal sequences and blocks with new sequences. After confirming a strong behavioural benefit of spatial-temporal predictability, we show lateralisation of beta oscillations in anticipation of the response associated with the upcoming target location and show that this also aligns to the expected timing of these forthcoming events. This effect was found both when comparing between repeated (learned) and new (unlearned) sequences, as well as when comparing targets that were expected after short vs. long intervals within the repeated (learned) sequence. Our findings suggest that learning of spatial-temporal structure leads to proactive and dynamic modulation of motor cortical excitability in anticipation of both the location and timing of events that are relevant to guide action. |
Hanna Heikkinen; Fariba Sharifian; Ricardo Vigario; Simo Vanni Feedback to distal dendrites links fMRI signals to neural receptive fields in a spiking network model of the visual cortex Journal Article Journal of Neurophysiology, 114 (1), pp. 57–69, 2015. Abstract | Links | BibTeX @article{Heikkinen2015,
title = {Feedback to distal dendrites links fMRI signals to neural receptive fields in a spiking network model of the visual cortex},
author = {Hanna Heikkinen and Fariba Sharifian and Ricardo Vigario and Simo Vanni},
url = {http://jn.physiology.org/lookup/doi/10.1152/jn.00169.2015},
doi = {10.1152/jn.00169.2015},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neurophysiology},
volume = {114},
number = {1},
pages = {57--69},
abstract = {The blood oxygenation level-dependent (BOLD) response has been strongly associated with neuronal activity in the brain. However, some neuronal tuning properties are consistently different from the BOLD response. We studied the spatial extent of neural and hemodynamic responses in the primary visual cortex, where the BOLD responses spread and interact over much longer distances than the small receptive fields of individual neurons would predict. Our model shows that a feedforward-feedback loop between V1 and a higher visual area can account for the observed spread of the BOLD response. In particular, anisotropic landing of inputs to compartmental neurons were necessary to account for the BOLD signal spread, while retaining realistic spiking responses. Our work shows that simple dendrites can separate tuning at the synapses and at the action potential output, thus bridging the BOLD signal to the neural receptive fields with high fidelity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The blood oxygenation level-dependent (BOLD) response has been strongly associated with neuronal activity in the brain. However, some neuronal tuning properties are consistently different from the BOLD response. We studied the spatial extent of neural and hemodynamic responses in the primary visual cortex, where the BOLD responses spread and interact over much longer distances than the small receptive fields of individual neurons would predict. Our model shows that a feedforward-feedback loop between V1 and a higher visual area can account for the observed spread of the BOLD response. In particular, anisotropic landing of inputs to compartmental neurons were necessary to account for the BOLD signal spread, while retaining realistic spiking responses. Our work shows that simple dendrites can separate tuning at the synapses and at the action potential output, thus bridging the BOLD signal to the neural receptive fields with high fidelity. |
John M Henderson; Wonil Choi; Steven G Luke Morphology of primary visual cortex predicts individual differences in fixation duration during text reading Journal Article Journal of Cognitive Neuroscience, 26 (12), pp. 2880–2888, 2014. Abstract | Links | BibTeX @article{Henderson2014,
title = {Morphology of primary visual cortex predicts individual differences in fixation duration during text reading},
author = {John M Henderson and Wonil Choi and Steven G Luke},
doi = {10.1162/jocn_a_00668},
year = {2014},
date = {2014-01-01},
journal = {Journal of Cognitive Neuroscience},
volume = {26},
number = {12},
pages = {2880--2888},
abstract = {In skilled reading, fixations are brief periods of time in which the eyes settle on words. E-Z Reader, a computational model of dynamic reading, posits that fixation durations are under realtime control of lexical processing. Lexical processing, in turn, requires efficient visual encoding. Here we tested the hypothesis that individual differences in fixation durations are related to individual differences in the efficiency of early visual encoding. To test this hypothesis, we recorded participantsʼ eye movements during reading. We then examined individual differences in fixation duration distributions as a function of individual differences in the morphology of primary visual cortex measured from MRI scans. The results showed that greater gray matter surface area and volume in visual cortex predicted shorter and less variable fixation durations in reading. These results suggest that individual differences in eye movements during skilled reading are related to initial visual encoding, consistent with models such as E-Z Reader that emphasize lexical control over fixation time.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In skilled reading, fixations are brief periods of time in which the eyes settle on words. E-Z Reader, a computational model of dynamic reading, posits that fixation durations are under realtime control of lexical processing. Lexical processing, in turn, requires efficient visual encoding. Here we tested the hypothesis that individual differences in fixation durations are related to individual differences in the efficiency of early visual encoding. To test this hypothesis, we recorded participantsʼ eye movements during reading. We then examined individual differences in fixation duration distributions as a function of individual differences in the morphology of primary visual cortex measured from MRI scans. The results showed that greater gray matter surface area and volume in visual cortex predicted shorter and less variable fixation durations in reading. These results suggest that individual differences in eye movements during skilled reading are related to initial visual encoding, consistent with models such as E-Z Reader that emphasize lexical control over fixation time. |
John M Henderson; Wonil Choi; Steven G Luke; Rutvik H Desai Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI Journal Article NeuroImage, 119 , pp. 390–397, 2015. Abstract | Links | BibTeX @article{Henderson2015,
title = {Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI},
author = {John M Henderson and Wonil Choi and Steven G Luke and Rutvik H Desai},
url = {http://dx.doi.org/10.1016/j.neuroimage.2015.06.072},
doi = {10.1016/j.neuroimage.2015.06.072},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage},
volume = {119},
pages = {390--397},
publisher = {Elsevier Inc.},
abstract = {A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading. |
John M Henderson; Wonil Choi; Matthew W Lowder; Fernanda Ferreira Language structure in the brain: A fixation-related fMRI study of syntactic surprisal in reading Journal Article NeuroImage, 132 , pp. 293–300, 2016. Abstract | Links | BibTeX @article{Henderson2016,
title = {Language structure in the brain: A fixation-related fMRI study of syntactic surprisal in reading},
author = {John M Henderson and Wonil Choi and Matthew W Lowder and Fernanda Ferreira},
url = {http://www.elsevier.com/inca/publications/store/6/2/2/9/2/5/index.htt%0Ahttp://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=emexb&NEWS=N&AN=608885794 http://dx.doi.org/10.1016/j.neuroimage.2016.02.050},
doi = {10.1016/j.neuroimage.2016.02.050},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {132},
pages = {293--300},
publisher = {Elsevier Inc.},
abstract = {How is syntactic analysis implemented by the human brain during language comprehension? The current study combined methods from computational linguistics, eyetracking, and fMRI to address this question. Subjects read passages of text presented as paragraphs while their eye movements were recorded in an MRI scanner. We parsed the text using a probabilistic context-free grammar to isolate syntactic difficulty. Syntactic difficulty was quantified as syntactic surprisal, which is related to the expectedness of a given word's syntactic category given its preceding context. We compared words with high and low syntactic surprisal values that were equated for length, frequency, and lexical surprisal, and used fixation-related (FIRE) fMRI to measure neural activity associated with syntactic surprisal for each fixated word. We observed greater neural activity for high than low syntactic surprisal in two predicted cortical regions previously identified with syntax: left inferior frontal gyrus (IFG) and less robustly, left anterior superior temporal lobe (ATL). These results support the hypothesis that left IFG and ATL play a central role in syntactic analysis during language comprehension. More generally, the results suggest a broader cortical network associated with syntactic prediction that includes increased activity in bilateral IFG and insula, as well as fusiform and right lingual gyri.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
How is syntactic analysis implemented by the human brain during language comprehension? The current study combined methods from computational linguistics, eyetracking, and fMRI to address this question. Subjects read passages of text presented as paragraphs while their eye movements were recorded in an MRI scanner. We parsed the text using a probabilistic context-free grammar to isolate syntactic difficulty. Syntactic difficulty was quantified as syntactic surprisal, which is related to the expectedness of a given word's syntactic category given its preceding context. We compared words with high and low syntactic surprisal values that were equated for length, frequency, and lexical surprisal, and used fixation-related (FIRE) fMRI to measure neural activity associated with syntactic surprisal for each fixated word. We observed greater neural activity for high than low syntactic surprisal in two predicted cortical regions previously identified with syntax: left inferior frontal gyrus (IFG) and less robustly, left anterior superior temporal lobe (ATL). These results support the hypothesis that left IFG and ATL play a central role in syntactic analysis during language comprehension. More generally, the results suggest a broader cortical network associated with syntactic prediction that includes increased activity in bilateral IFG and insula, as well as fusiform and right lingual gyri. |
John M Henderson; Wonil Choi; Steven G Luke; Joseph Schmidt Neural correlates of individual differences in fixation duration during natural reading Journal Article Quarterly Journal of Experimental Psychology, 71 (1), pp. 314–323, 2018. Abstract | Links | BibTeX @article{Henderson2018,
title = {Neural correlates of individual differences in fixation duration during natural reading},
author = {John M Henderson and Wonil Choi and Steven G Luke and Joseph Schmidt},
doi = {10.1080/17470218.2017.1329322},
year = {2018},
date = {2018-01-01},
journal = {Quarterly Journal of Experimental Psychology},
volume = {71},
number = {1},
pages = {314--323},
abstract = {Reading requires integration of language and cognitive processes with attention and eye movement control. Individuals differ in their reading ability, but little is known about the neurocognitive processes associated with these individual differences. To investigate this issue, we combined eyetracking and functional magnetic resonance imaging (fMRI), simultaneously recording eye movements and blood oxygen level dependent (BOLD) activity while subjects read text passages. We found that the variability and skew of fixation duration distributions across individuals, as assessed by ex-Gaussian analyses, decreased with increasing neural activity in regions associated with the cortical eye movement control network (left frontal eye fields [FEF], left intraparietal sulcus [IPS] , left inferior frontal gyrus [IFG] and right IFG). The results suggest that individual differences in fixation duration during reading are related to underlying neurocognitive processes associated with the eye movement control system and its relationship to language processing. The results also show that eye movements and fMRI can be combined to investigate the neural correlates of individual differences in natural reading.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Reading requires integration of language and cognitive processes with attention and eye movement control. Individuals differ in their reading ability, but little is known about the neurocognitive processes associated with these individual differences. To investigate this issue, we combined eyetracking and functional magnetic resonance imaging (fMRI), simultaneously recording eye movements and blood oxygen level dependent (BOLD) activity while subjects read text passages. We found that the variability and skew of fixation duration distributions across individuals, as assessed by ex-Gaussian analyses, decreased with increasing neural activity in regions associated with the cortical eye movement control network (left frontal eye fields [FEF], left intraparietal sulcus [IPS] , left inferior frontal gyrus [IFG] and right IFG). The results suggest that individual differences in fixation duration during reading are related to underlying neurocognitive processes associated with the eye movement control system and its relationship to language processing. The results also show that eye movements and fMRI can be combined to investigate the neural correlates of individual differences in natural reading. |
Erno J Hermans; Jonathan W Kanen; Arielle Tambini; Guillén Fernández; Lila Davachi; Elizabeth A Phelps Persistence of amygdala-hippocampal connectivity and multi-voxel correlation structures during awake rest after fear learning predicts long-term expression of fear Journal Article Cerebral Cortex, 27 (5), pp. 3028–3041, 2017. Abstract | Links | BibTeX @article{Hermans2017,
title = {Persistence of amygdala-hippocampal connectivity and multi-voxel correlation structures during awake rest after fear learning predicts long-term expression of fear},
author = {Erno J Hermans and Jonathan W Kanen and Arielle Tambini and Guillén Fernández and Lila Davachi and Elizabeth A Phelps},
doi = {10.1093/cercor/bhw145},
year = {2017},
date = {2017-01-01},
journal = {Cerebral Cortex},
volume = {27},
number = {5},
pages = {3028--3041},
abstract = {After encoding, memories undergo a process of consolidation that determines long-term retention. For conditioned fear, animal models postulate that consolidation involves reactivations of neuronal assemblies supporting fear learning during postlearning " offline " periods. However, no human studies to date have investigated such processes, particularly in relation to long-term expression of fear. We tested 24 participants using functional MRI on 2 consecutive days in a fear conditioning paradigm involving 1 habituation block, 2 acquisition blocks, and 2 extinction blocks on day 1, and 2 re-extinction blocks on day 2. Conditioning blocks were preceded and followed by 4.5-min rest blocks. Strength of spontaneous recovery of fear on day 2 served as a measure of long-term expression of fear. Amygdala connectivity primarily with hippocampus increased progressively during postacquisition and postextinction rest on day 1. Intraregional multi-voxel correlation structures within amygdala and hippocampus sampled during a block of differential fear conditioning furthermore persisted after fear learning. Critically, both these main findings were stronger in participants who exhibited spontaneous recovery 24 h later. Our findings indicate that neural circuits activated during fear conditioning exhibit persistent postlearning activity that may be functionally relevant in promoting consolidation of the fear memory.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
After encoding, memories undergo a process of consolidation that determines long-term retention. For conditioned fear, animal models postulate that consolidation involves reactivations of neuronal assemblies supporting fear learning during postlearning " offline " periods. However, no human studies to date have investigated such processes, particularly in relation to long-term expression of fear. We tested 24 participants using functional MRI on 2 consecutive days in a fear conditioning paradigm involving 1 habituation block, 2 acquisition blocks, and 2 extinction blocks on day 1, and 2 re-extinction blocks on day 2. Conditioning blocks were preceded and followed by 4.5-min rest blocks. Strength of spontaneous recovery of fear on day 2 served as a measure of long-term expression of fear. Amygdala connectivity primarily with hippocampus increased progressively during postacquisition and postextinction rest on day 1. Intraregional multi-voxel correlation structures within amygdala and hippocampus sampled during a block of differential fear conditioning furthermore persisted after fear learning. Critically, both these main findings were stronger in participants who exhibited spontaneous recovery 24 h later. Our findings indicate that neural circuits activated during fear conditioning exhibit persistent postlearning activity that may be functionally relevant in promoting consolidation of the fear memory. |
Katrin Herrmann; Leila Montaser-Kouhsari; Marisa Carrasco; David J Heeger When size matters: Attention affects performance by contrast or response gain Journal Article Nature Neuroscience, 13 (12), pp. 1554–1561, 2010. Abstract | Links | BibTeX @article{Herrmann2010,
title = {When size matters: Attention affects performance by contrast or response gain},
author = {Katrin Herrmann and Leila Montaser-Kouhsari and Marisa Carrasco and David J Heeger},
url = {http://dx.doi.org/10.1038/nn.2669},
doi = {10.1038/nn.2669},
year = {2010},
date = {2010-01-01},
journal = {Nature Neuroscience},
volume = {13},
number = {12},
pages = {1554--1561},
publisher = {Nature Publishing Group},
abstract = {Covert attention, the selective processing of visual information in the absence of eye movements, improves behavioral performance. Here, we show that attention, both exogenous (involuntary) and endogenous (voluntary), can affect performance by contrast or response gain changes, depending on the stimulus size and the relative size of the attention field. These two variables were manipulated in a cueing task while varying stimulus contrast. We observed a change in behavioral performance consonant with a change in contrast gain for small stimuli paired with spatial uncertainty, but a change in response gain for large stimuli presented at one location (no uncertainty) and surrounded by irrelevant flanking distracters. A complementary neuroimaging experiment revealed that observers' attention field was wider with than without spatial uncertainty. Our results support key predictions of the normalization model of attention, and reconcile previous, seemingly contradictory, findings on the effects of visual attention. Introduction},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Covert attention, the selective processing of visual information in the absence of eye movements, improves behavioral performance. Here, we show that attention, both exogenous (involuntary) and endogenous (voluntary), can affect performance by contrast or response gain changes, depending on the stimulus size and the relative size of the attention field. These two variables were manipulated in a cueing task while varying stimulus contrast. We observed a change in behavioral performance consonant with a change in contrast gain for small stimuli paired with spatial uncertainty, but a change in response gain for large stimuli presented at one location (no uncertainty) and surrounded by irrelevant flanking distracters. A complementary neuroimaging experiment revealed that observers' attention field was wider with than without spatial uncertainty. Our results support key predictions of the normalization model of attention, and reconcile previous, seemingly contradictory, findings on the effects of visual attention. Introduction |
Nora A Herweg; Bernd Weber; Anna Kasparbauer; Inga Meyhöfer; Maria Steffens; Nikos Smyrnis; Ulrich Ettinger Functional magnetic resonance imaging of sensorimotor transformations in saccades and antisaccades Journal Article NeuroImage, 102 , pp. 848–860, 2014. Abstract | Links | BibTeX @article{Herweg2014,
title = {Functional magnetic resonance imaging of sensorimotor transformations in saccades and antisaccades},
author = {Nora A Herweg and Bernd Weber and Anna Kasparbauer and Inga Meyhöfer and Maria Steffens and Nikos Smyrnis and Ulrich Ettinger},
doi = {10.1016/j.neuroimage.2014.08.033},
year = {2014},
date = {2014-01-01},
journal = {NeuroImage},
volume = {102},
pages = {848--860},
abstract = {Saccades to peripheral targets require a direct visuomotor transformation. In contrast, antisaccades, saccades in opposite direction of a peripheral target, require more complex transformation processes due to the inversion of the spatial vector. Here, the differential neural mechanisms underlying sensorimotor control in saccades and antisaccades were investigated using functional magnetic resonance imaging (fMRI) at 3. T field strength in 22 human volunteers. We combined a task factor (prosaccades: look towards target; antisaccades: look away from target) with a parametric factor of transformation demand (single vs. multiple peripheral targets) in a two-factorial block design. Behaviorally, a greater number of peripheral targets resulted in decreased spatial accuracy and increased reaction times in antisaccades. No effects were seen on the percentage of antisaccade direction errors or on any prosaccade measures. Neurally, a greater number of targets led to increased BOLD signal in the posterior parietal cortex (PPC) bilaterally. This effect was partially qualified by an interaction that extended into somatosensory cortex, indicating greater increases during antisaccades than prosaccades. The results implicate the PPC as a sensorimotor interface that is especially important in nonstandard mapping for antisaccades and point to a supportive role of somatosensory areas in antisaccade sensorimotor control, possibly by means of proprioceptive processes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Saccades to peripheral targets require a direct visuomotor transformation. In contrast, antisaccades, saccades in opposite direction of a peripheral target, require more complex transformation processes due to the inversion of the spatial vector. Here, the differential neural mechanisms underlying sensorimotor control in saccades and antisaccades were investigated using functional magnetic resonance imaging (fMRI) at 3. T field strength in 22 human volunteers. We combined a task factor (prosaccades: look towards target; antisaccades: look away from target) with a parametric factor of transformation demand (single vs. multiple peripheral targets) in a two-factorial block design. Behaviorally, a greater number of peripheral targets resulted in decreased spatial accuracy and increased reaction times in antisaccades. No effects were seen on the percentage of antisaccade direction errors or on any prosaccade measures. Neurally, a greater number of targets led to increased BOLD signal in the posterior parietal cortex (PPC) bilaterally. This effect was partially qualified by an interaction that extended into somatosensory cortex, indicating greater increases during antisaccades than prosaccades. The results implicate the PPC as a sensorimotor interface that is especially important in nonstandard mapping for antisaccades and point to a supportive role of somatosensory areas in antisaccade sensorimotor control, possibly by means of proprioceptive processes. |
Jörn M Horschig; Ole Jensen; Martine R van Schouwenburg; Roshan Cools; Mathilde Bonnefond Alpha activity reflects individual abilities to adapt to the environment Journal Article NeuroImage, 89 , pp. 235–243, 2014. Abstract | Links | BibTeX @article{Horschig2014,
title = {Alpha activity reflects individual abilities to adapt to the environment},
author = {Jörn M Horschig and Ole Jensen and Martine R van Schouwenburg and Roshan Cools and Mathilde Bonnefond},
url = {http://dx.doi.org/10.1016/j.neuroimage.2013.12.018},
doi = {10.1016/j.neuroimage.2013.12.018},
year = {2014},
date = {2014-01-01},
journal = {NeuroImage},
volume = {89},
pages = {235--243},
publisher = {Elsevier Inc.},
abstract = {Recent findings suggest that oscillatory alpha activity (7-13. Hz) is associated with functional inhibition of sensory regions by filtering incoming information. Accordingly the alpha power in visual regions varies in anticipation of upcoming, predictable stimuli which has consequences for visual processing and subsequent behavior. In covert spatial attention studies it has been demonstrated that performance correlates with the adaptation of alpha power in response to explicit spatial cueing. However it remains unknown whether such an adaptation also occurs in response to implicit statistical properties of a task. In a covert attention switching paradigm, we here show evidence that individuals differ on how they adapt to implicit statistical properties of the task. Subjects whose behavioral performance reflects the implicit change in switch trial likelihood show strong adjustment of anticipatory alpha power lateralization. Most importantly, the stronger the behavioral adjustment to the switch trial likelihood was, the stronger the adjustment of anticipatory posterior alpha lateralization. We conclude that anticipatory spatial attention is reflected in the distribution of posterior alpha band power which is predictive of individual detection performance in response to the implicit statistical properties of the task.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Recent findings suggest that oscillatory alpha activity (7-13. Hz) is associated with functional inhibition of sensory regions by filtering incoming information. Accordingly the alpha power in visual regions varies in anticipation of upcoming, predictable stimuli which has consequences for visual processing and subsequent behavior. In covert spatial attention studies it has been demonstrated that performance correlates with the adaptation of alpha power in response to explicit spatial cueing. However it remains unknown whether such an adaptation also occurs in response to implicit statistical properties of a task. In a covert attention switching paradigm, we here show evidence that individuals differ on how they adapt to implicit statistical properties of the task. Subjects whose behavioral performance reflects the implicit change in switch trial likelihood show strong adjustment of anticipatory alpha power lateralization. Most importantly, the stronger the behavioral adjustment to the switch trial likelihood was, the stronger the adjustment of anticipatory posterior alpha lateralization. We conclude that anticipatory spatial attention is reflected in the distribution of posterior alpha band power which is predictive of individual detection performance in response to the implicit statistical properties of the task. |
Jörn M Horschig; Wouter Oosterheert; Robert Oostenveld; Ole Jensen Modulation of posterior alpha activity by spatial attention allows for controlling a continuous brain–computer interface Journal Article Brain Topography, 28 (6), pp. 852–864, 2015. Abstract | Links | BibTeX @article{Horschig2015,
title = {Modulation of posterior alpha activity by spatial attention allows for controlling a continuous brain–computer interface},
author = {Jörn M Horschig and Wouter Oosterheert and Robert Oostenveld and Ole Jensen},
doi = {10.1007/s10548-014-0401-7},
year = {2015},
date = {2015-01-01},
journal = {Brain Topography},
volume = {28},
number = {6},
pages = {852--864},
abstract = {Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing. |
Jaakko Hotta; Jukka Saari; Miika Koskinen; Yevhen Hlushchuk; Nina Forss; Riitta Hari Abnormal brain responses to action observation in complex regional pain syndrome Journal Article Journal of Pain, 18 (3), pp. 255–265, 2017. Abstract | Links | BibTeX @article{Hotta2017,
title = {Abnormal brain responses to action observation in complex regional pain syndrome},
author = {Jaakko Hotta and Jukka Saari and Miika Koskinen and Yevhen Hlushchuk and Nina Forss and Riitta Hari},
url = {http://dx.doi.org/10.1016/j.jpain.2016.10.017},
doi = {10.1016/j.jpain.2016.10.017},
year = {2017},
date = {2017-01-01},
journal = {Journal of Pain},
volume = {18},
number = {3},
pages = {255--265},
publisher = {Elsevier Inc},
abstract = {Patients with complex regional pain syndrome (CRPS) display various abnormalities in central motor function, and their pain is intensified when they perform or just observe motor actions. In this study, we examined the abnormalities of brain responses to action observation in CRPS. We analyzed 3-T functional magnetic resonance images from 13 upper limb CRPS patients (all female, ages 31–58 years) and 13 healthy, age- and sex-matched control subjects. The functional magnetic resonance imaging data were acquired while the subjects viewed brief videos of hand actions shown in the first-person perspective. A pattern-classification analysis was applied to characterize brain areas where the activation pattern differed between CRPS patients and healthy subjects. Brain areas with statistically significant group differences (q textless .05, false discovery rate-corrected) included the hand representation area in the sensorimotor cortex, inferior frontal gyrus, secondary somatosensory cortex, inferior parietal lobule, orbitofrontal cortex, and thalamus. Our findings indicate that CRPS impairs action observation by affecting brain areas related to pain processing and motor control. Perspective This article shows that in CRPS, the observation of others' motor actions induces abnormal neural activity in brain areas essential for sensorimotor functions and pain. These results build the cerebral basis for action-observation impairments in CRPS.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Patients with complex regional pain syndrome (CRPS) display various abnormalities in central motor function, and their pain is intensified when they perform or just observe motor actions. In this study, we examined the abnormalities of brain responses to action observation in CRPS. We analyzed 3-T functional magnetic resonance images from 13 upper limb CRPS patients (all female, ages 31–58 years) and 13 healthy, age- and sex-matched control subjects. The functional magnetic resonance imaging data were acquired while the subjects viewed brief videos of hand actions shown in the first-person perspective. A pattern-classification analysis was applied to characterize brain areas where the activation pattern differed between CRPS patients and healthy subjects. Brain areas with statistically significant group differences (q textless .05, false discovery rate-corrected) included the hand representation area in the sensorimotor cortex, inferior frontal gyrus, secondary somatosensory cortex, inferior parietal lobule, orbitofrontal cortex, and thalamus. Our findings indicate that CRPS impairs action observation by affecting brain areas related to pain processing and motor control. Perspective This article shows that in CRPS, the observation of others' motor actions induces abnormal neural activity in brain areas essential for sensorimotor functions and pain. These results build the cerebral basis for action-observation impairments in CRPS. |
A Hummer; M Ritter; M Tik; A A Ledolter; M Woletz; G E Holder; S O Dumoulinef; U Schmidt-Erfurth; C Windischberger; S O Dumoulin; U Schmidt-Erfurth; C Windischberger Eyetracker-based gaze correction for robust mapping of population receptive fields Journal Article NeuroImage, 142 , pp. 211–224, 2016. Abstract | Links | BibTeX @article{Hummer2016,
title = {Eyetracker-based gaze correction for robust mapping of population receptive fields},
author = {A Hummer and M Ritter and M Tik and A A Ledolter and M Woletz and G E Holder and S O Dumoulinef and U Schmidt-Erfurth and C Windischberger and S O Dumoulin and U Schmidt-Erfurth and C Windischberger},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.07.003},
doi = {10.1016/j.neuroimage.2016.07.003},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {142},
pages = {211--224},
publisher = {Elsevier B.V.},
abstract = {Functional MRI enables the acquisition of a retinotopic map that relates regions of the visual field to neural populations in the visual cortex. During such a “population receptive field” (PRF) experiment, stable gaze fixation is of utmost importance in order to correctly link the presented stimulus patterns to stimulated retinal regions and the resulting Blood Oxygen Level Dependent (BOLD) response of the appropriate region within the visual cortex. A method is described that compensates for unstable gaze fixation by recording gaze position via an eyetracker and subsequently modifies the input stimulus underlying the PRF analysis according to the eyetracking measures. Here we show that PRF maps greatly improve when the method is applied to data acquired with either saccadic or smooth eye movements. We conclude that the technique presented herein is useful for studies involving subjects with unstable gaze fixation, particularly elderly patient populations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Functional MRI enables the acquisition of a retinotopic map that relates regions of the visual field to neural populations in the visual cortex. During such a “population receptive field” (PRF) experiment, stable gaze fixation is of utmost importance in order to correctly link the presented stimulus patterns to stimulated retinal regions and the resulting Blood Oxygen Level Dependent (BOLD) response of the appropriate region within the visual cortex. A method is described that compensates for unstable gaze fixation by recording gaze position via an eyetracker and subsequently modifies the input stimulus underlying the PRF analysis according to the eyetracking measures. Here we show that PRF maps greatly improve when the method is applied to data acquired with either saccadic or smooth eye movements. We conclude that the technique presented herein is useful for studies involving subjects with unstable gaze fixation, particularly elderly patient populations. |
Akiko Ikkai; Sangita Dandekar; Clayton E Curtis Lateralization in alpha-band oscillations predicts the locus and spatial distribution of attention Journal Article PLoS ONE, 11 (5), pp. 1–17, 2016. Abstract | Links | BibTeX @article{Ikkai2016,
title = {Lateralization in alpha-band oscillations predicts the locus and spatial distribution of attention},
author = {Akiko Ikkai and Sangita Dandekar and Clayton E Curtis},
doi = {10.1371/journal.pone.0154796},
year = {2016},
date = {2016-01-01},
journal = {PLoS ONE},
volume = {11},
number = {5},
pages = {1--17},
abstract = {Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8-13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target's location, while on others it contained no spatial information. When the target's location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target's location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8-13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target's location, while on others it contained no spatial information. When the target's location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target's location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex. |
Monika Intaitė; João Valente Duarte; Miguel Castelo-Branco Working memory load influences perceptual ambiguity by competing for fronto-parietal attentional resources Journal Article Brain Research, 1650 , pp. 142–151, 2016. Abstract | Links | BibTeX @article{Intaite2016,
title = {Working memory load influences perceptual ambiguity by competing for fronto-parietal attentional resources},
author = {Monika Intaitė and Jo{ã}o Valente Duarte and Miguel Castelo-Branco},
doi = {10.1016/j.brainres.2016.08.044},
year = {2016},
date = {2016-01-01},
journal = {Brain Research},
volume = {1650},
pages = {142--151},
abstract = {A visual stimulus is defined as ambiguous when observers perceive it as having at least two distinct and spontaneously alternating interpretations. Neuroimaging studies suggest an involvement of a right fronto-parietal network regulating the balance between stable percepts and the triggering of alternative interpretations. As spontaneous perceptual reversals may occur even in the absence of attention to these stimuli, we investigated neural activity patterns in response to perceptual changes of ambiguous Necker cube under different amounts of working memory load using a dual-task design. We hypothesized that the same regions that process working memory load are involved in perceptual switching and confirmed the prediction that perceptual reversals led to fMRI responses that linearly depended on load. Accordingly, posterior Superior Parietal Lobule, anterior Prefrontal and Dorsolateral Prefrontal cortices exhibited differential BOLD signal changes in response to perceptual reversals under working memory load. Our results also suggest that the posterior Superior Parietal Lobule may be directly involved in the emergence of perceptual reversals, given that it specifically reflects both perceptual versus real changes and load levels. The anterior Prefrontal and Dorsolateral Prefrontal cortices, showing a significant interaction between reversal levels and load, might subserve a modulatory role in such reversals, in a mirror symmetric way: in the former activation is suppressed by the highest loads, and in the latter deactivation is reduced by highest loads, suggesting a more direct role of the aPFC in reversal generation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A visual stimulus is defined as ambiguous when observers perceive it as having at least two distinct and spontaneously alternating interpretations. Neuroimaging studies suggest an involvement of a right fronto-parietal network regulating the balance between stable percepts and the triggering of alternative interpretations. As spontaneous perceptual reversals may occur even in the absence of attention to these stimuli, we investigated neural activity patterns in response to perceptual changes of ambiguous Necker cube under different amounts of working memory load using a dual-task design. We hypothesized that the same regions that process working memory load are involved in perceptual switching and confirmed the prediction that perceptual reversals led to fMRI responses that linearly depended on load. Accordingly, posterior Superior Parietal Lobule, anterior Prefrontal and Dorsolateral Prefrontal cortices exhibited differential BOLD signal changes in response to perceptual reversals under working memory load. Our results also suggest that the posterior Superior Parietal Lobule may be directly involved in the emergence of perceptual reversals, given that it specifically reflects both perceptual versus real changes and load levels. The anterior Prefrontal and Dorsolateral Prefrontal cortices, showing a significant interaction between reversal levels and load, might subserve a modulatory role in such reversals, in a mirror symmetric way: in the former activation is suppressed by the highest loads, and in the latter deactivation is reduced by highest loads, suggesting a more direct role of the aPFC in reversal generation. |
Leyla Isik; Ethan M Meyers; Joel Z Leibo; Tomaso Poggio The dynamics of invariant object recognition in the human visual system Journal Article Journal of Neurophysiology, 111 (1), pp. 91–102, 2014. Abstract | Links | BibTeX @article{Isik2014,
title = {The dynamics of invariant object recognition in the human visual system},
author = {Leyla Isik and Ethan M Meyers and Joel Z Leibo and Tomaso Poggio},
url = {http://jn.physiology.org/cgi/doi/10.1152/jn.00394.2013},
doi = {10.1152/jn.00394.2013},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neurophysiology},
volume = {111},
number = {1},
pages = {91--102},
abstract = {The human visual system can rapidly recognize objects despite transformations that alter their appearance. The precise timing of when the brain computes neural representations that are invariant to particular transformations, however, has not been mapped in humans. Here we employ magnetoencephalography decoding analysis to measure the dynamics of size- and position-invariant visual information development in the ventral visual stream. With this method we can read out the identity of objects beginning as early as 60 ms. Size- and position-invariant visual information appear around 125 ms and 150 ms, respectively, and both develop in stages, with invariance to smaller transformations arising before invariance to larger transformations. Additionally, the magnetoencephalography sensor activity localizes to neural sources that are in the most posterior occipital regions at the early decoding times and then move temporally as invariant information develops. These results provide previously unknown latencies for key stages of human-invariant object recognition, as well as new and compelling evidence for a feed-forward hierarchical model of invariant object recognition where invariance increases at each successive visual area along the ventral stream.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The human visual system can rapidly recognize objects despite transformations that alter their appearance. The precise timing of when the brain computes neural representations that are invariant to particular transformations, however, has not been mapped in humans. Here we employ magnetoencephalography decoding analysis to measure the dynamics of size- and position-invariant visual information development in the ventral visual stream. With this method we can read out the identity of objects beginning as early as 60 ms. Size- and position-invariant visual information appear around 125 ms and 150 ms, respectively, and both develop in stages, with invariance to smaller transformations arising before invariance to larger transformations. Additionally, the magnetoencephalography sensor activity localizes to neural sources that are in the most posterior occipital regions at the early decoding times and then move temporally as invariant information develops. These results provide previously unknown latencies for key stages of human-invariant object recognition, as well as new and compelling evidence for a feed-forward hierarchical model of invariant object recognition where invariance increases at each successive visual area along the ventral stream. |
Sharna D Jamadar; Beth P Johnson; Meaghan Clough; Gary F Egan; Joanne Fielding Behavioral and neural plasticity of ocular motor control: Changes in performance and fMRI activity following antisaccade training Journal Article Frontiers in Human Nuroscience, 9 (653), pp. 1–13, 2015. Abstract | Links | BibTeX @article{Jamadar2015,
title = {Behavioral and neural plasticity of ocular motor control: Changes in performance and fMRI activity following antisaccade training},
author = {Sharna D Jamadar and Beth P Johnson and Meaghan Clough and Gary F Egan and Joanne Fielding},
url = {http://journal.frontiersin.org/Article/10.3389/fnhum.2015.00653/abstract},
doi = {10.3389/fnhum.2015.00653},
year = {2015},
date = {2015-01-01},
journal = {Frontiers in Human Nuroscience},
volume = {9},
number = {653},
pages = {1--13},
abstract = {The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behavior against the volitional control of a goal-directed behavior. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behavior and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following 2 weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following 2 weeks of training; however this increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus, and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behavior against the volitional control of a goal-directed behavior. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behavior and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following 2 weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following 2 weeks of training; however this increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus, and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. |
Su Keun Jeong; Yaoda Xu The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex Journal Article Journal of Vision, 16 (10), pp. 1–21, 2016. Abstract | Links | BibTeX @article{Jeong2016,
title = {The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex},
author = {Su Keun Jeong and Yaoda Xu},
url = {http://dx.doi.org/10.1167/16.10.2},
doi = {10.1167/16.10.2},
year = {2016},
date = {2016-01-01},
journal = {Journal of Vision},
volume = {16},
number = {10},
pages = {1--21},
abstract = {The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region. |
Su Keun Jeong; Yaoda Xu Task-context-dependent linear representation of multiple visual objects in human parietal cortex Journal Article Journal of Cognitive Neuroscience, 29 (10), pp. 1778–1789, 2017. Abstract | Links | BibTeX @article{Jeong2017,
title = {Task-context-dependent linear representation of multiple visual objects in human parietal cortex},
author = {Su Keun Jeong and Yaoda Xu},
url = {www.brainvoyager.com},
doi = {10.1162/jocn_a_01156},
year = {2017},
date = {2017-01-01},
journal = {Journal of Cognitive Neuroscience},
volume = {29},
number = {10},
pages = {1778--1789},
abstract = {A host of recent studies have reported robust representations of visual object information in the human parietal cortex, similar to those found in ventral visual cortex. In ventral visual cortex, both monkey neurophysiology and human fMRI studies showed that the neural representation ofa pair ofunrelated objects can be approximated by the averaged neural representation of the constituent objects shown in isolation. In this study, we examined whether such a linear relationship between objects exists for object representations in the human parietal cortex. Using fMRI and multivoxel pattern analysis, we examined object representations in human inferior and superior intraparietal sulcus, two parietal regions previously implicated in visual object selection and encoding, respectively. We also examined responses from the lateral occipital region, a ventral object processing area. We obtained fMRI response patterns to object pairs and their constituent objects shown in isolation while participants viewed these objects and performed a 1-back repetition detection task. By measuring fMRI response pattern correlations, we found that all three brain regions contained representations for both single object and object pairs. In the lateral occipital region, the representation for a pair ofobjects could be reliably approximated by the average representation of its constituent objects shown in isolation, replicating previous findings in ventral visual cortex. Such a simple linear relationship, however, was not observed in either parietal region examined. Nevertheless, when we equated the amount of task information present by examining responses from two pairs of objects, we found that representations for the average of two object pairs were indistinguishable in both parietal regions from the average of another two object pairs containing the same four component objects but with a different pairing of the objects (i.e., the average of AB and CD vs. that of AD and CB). Thus, when task information was held consistent, the same linear relationship may govern how multiple independent objects are represented in the human parietal cortex as it does in ventral visual cortex. These findings show that object and task representations coexist in the human parietal cortex and characterize one significant dif- ference of how visual information may be represented in ventral visual and parietal regions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A host of recent studies have reported robust representations of visual object information in the human parietal cortex, similar to those found in ventral visual cortex. In ventral visual cortex, both monkey neurophysiology and human fMRI studies showed that the neural representation ofa pair ofunrelated objects can be approximated by the averaged neural representation of the constituent objects shown in isolation. In this study, we examined whether such a linear relationship between objects exists for object representations in the human parietal cortex. Using fMRI and multivoxel pattern analysis, we examined object representations in human inferior and superior intraparietal sulcus, two parietal regions previously implicated in visual object selection and encoding, respectively. We also examined responses from the lateral occipital region, a ventral object processing area. We obtained fMRI response patterns to object pairs and their constituent objects shown in isolation while participants viewed these objects and performed a 1-back repetition detection task. By measuring fMRI response pattern correlations, we found that all three brain regions contained representations for both single object and object pairs. In the lateral occipital region, the representation for a pair ofobjects could be reliably approximated by the average representation of its constituent objects shown in isolation, replicating previous findings in ventral visual cortex. Such a simple linear relationship, however, was not observed in either parietal region examined. Nevertheless, when we equated the amount of task information present by examining responses from two pairs of objects, we found that representations for the average of two object pairs were indistinguishable in both parietal regions from the average of another two object pairs containing the same four component objects but with a different pairing of the objects (i.e., the average of AB and CD vs. that of AD and CB). Thus, when task information was held consistent, the same linear relationship may govern how multiple independent objects are represented in the human parietal cortex as it does in ventral visual cortex. These findings show that object and task representations coexist in the human parietal cortex and characterize one significant dif- ference of how visual information may be represented in ventral visual and parietal regions. |
Trenton A Jerde; Elisha P Merriam; Adam C Riggall; James H Hedges; Clayton E Curtis Prioritized maps of space in human frontoparietal cortex Journal Article Journal of Neuroscience, 32 (48), pp. 17382–17390, 2012. Abstract | Links | BibTeX @article{Jerde2012,
title = {Prioritized maps of space in human frontoparietal cortex},
author = {Trenton A Jerde and Elisha P Merriam and Adam C Riggall and James H Hedges and Clayton E Curtis},
url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.3810-12.2012},
doi = {10.1523/JNEUROSCI.3810-12.2012},
year = {2012},
date = {2012-01-01},
journal = {Journal of Neuroscience},
volume = {32},
number = {48},
pages = {17382--17390},
abstract = {Priority maps are theorized to be composed of large populations of neurons organized topographically into a map of gaze-centered space whose activity spatially tags salient and behaviorally relevant information. Here, we identified four priority map candidates along human posterior intraparietal sulcus (IPS0-IPS3) and two along the precentral sulcus (PCS) that contained reliable retinotopically organized maps of contralateral visual space. Persistent activity increased from posterior-to-anterior IPS areas and from inferior-to-superior PCS areas during the maintenance of a working memory representation, the maintenance of covert attention, and the maintenance of a saccade plan. Moreover, decoders trained to predict the locations on one task (e.g., working memory) cross-predicted the locations on other tasks (e.g., attention) in superior PCS and IPS2, suggesting that these patterns of maintenance activity may be interchangeable across the tasks. Such properties make these two areas in frontal and parietal cortex viable priority map candidates.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Priority maps are theorized to be composed of large populations of neurons organized topographically into a map of gaze-centered space whose activity spatially tags salient and behaviorally relevant information. Here, we identified four priority map candidates along human posterior intraparietal sulcus (IPS0-IPS3) and two along the precentral sulcus (PCS) that contained reliable retinotopically organized maps of contralateral visual space. Persistent activity increased from posterior-to-anterior IPS areas and from inferior-to-superior PCS areas during the maintenance of a working memory representation, the maintenance of covert attention, and the maintenance of a saccade plan. Moreover, decoders trained to predict the locations on one task (e.g., working memory) cross-predicted the locations on other tasks (e.g., attention) in superior PCS and IPS2, suggesting that these patterns of maintenance activity may be interchangeable across the tasks. Such properties make these two areas in frontal and parietal cortex viable priority map candidates. |
Zoran Josipovic; Ilan Dinstein; Jochen Weber; David J Heeger Influence of meditation on anti-correlated networks in the brain Journal Article Frontiers in Human Neuroscience, 5 , pp. 1–11, 2012. Abstract | Links | BibTeX @article{Josipovic2012,
title = {Influence of meditation on anti-correlated networks in the brain},
author = {Zoran Josipovic and Ilan Dinstein and Jochen Weber and David J Heeger},
url = {http://journal.frontiersin.org/article/10.3389/fnhum.2011.00183/abstract},
doi = {10.3389/fnhum.2011.00183},
year = {2012},
date = {2012-01-01},
journal = {Frontiers in Human Neuroscience},
volume = {5},
pages = {1--11},
abstract = {Human experiences can be broadly divided into those that are external and related to interaction with the environment, and experiences that are internal and self-related. The cerebral cortex appears to be divided into two corresponding systems: an "extrinsic" system composed of brain areas that respond more to external stimuli and tasks and an "intrinsic" system composed of brain areas that respond less to external stimuli and tasks. These two broad brain systems seem to compete with each other, such that their activity levels over time is usually anti-correlated, even when subjects are "at rest" and not performing any task. This study used meditation as an experimental manipulation to test whether this competition (anti-correlation) can be modulated by cognitive strategy. Participants either fixated without meditation (fixation), or engaged in non-dual awareness (NDA) or focused attention (FA) meditations. We computed inter-area correlations ("functional connectivity") between pairs of brain regions within each system, and between the entire extrinsic and intrinsic systems. Anti-correlation between extrinsic vs. intrinsic systems was stronger during FA meditation and weaker during NDA meditation in comparison to fixation (without mediation). However, correlation between areas within each system did not change across conditions. These results suggest that the anti-correlation found between extrinsic and intrinsic systems is not an immutable property of brain organization and that practicing different forms of meditation can modulate this gross functional organization in profoundly different ways.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Human experiences can be broadly divided into those that are external and related to interaction with the environment, and experiences that are internal and self-related. The cerebral cortex appears to be divided into two corresponding systems: an "extrinsic" system composed of brain areas that respond more to external stimuli and tasks and an "intrinsic" system composed of brain areas that respond less to external stimuli and tasks. These two broad brain systems seem to compete with each other, such that their activity levels over time is usually anti-correlated, even when subjects are "at rest" and not performing any task. This study used meditation as an experimental manipulation to test whether this competition (anti-correlation) can be modulated by cognitive strategy. Participants either fixated without meditation (fixation), or engaged in non-dual awareness (NDA) or focused attention (FA) meditations. We computed inter-area correlations ("functional connectivity") between pairs of brain regions within each system, and between the entire extrinsic and intrinsic systems. Anti-correlation between extrinsic vs. intrinsic systems was stronger during FA meditation and weaker during NDA meditation in comparison to fixation (without mediation). However, correlation between areas within each system did not change across conditions. These results suggest that the anti-correlation found between extrinsic and intrinsic systems is not an immutable property of brain organization and that practicing different forms of meditation can modulate this gross functional organization in profoundly different ways. |
Anna Maria Kasparbauer; Inga Meyhöfer; Maria Steffens; Bernd Weber; Merve Aydin; Veena Kumari; Rene Hurlemann; Ulrich Ettinger Neural effects of methylphenidate and nicotine during smooth pursuit eye movements Journal Article NeuroImage, 141 , pp. 52–59, 2016. Abstract | Links | BibTeX @article{Kasparbauer2016,
title = {Neural effects of methylphenidate and nicotine during smooth pursuit eye movements},
author = {Anna Maria Kasparbauer and Inga Meyhöfer and Maria Steffens and Bernd Weber and Merve Aydin and Veena Kumari and Rene Hurlemann and Ulrich Ettinger},
url = {http://dx.doi.org/10.1016/j.neuroimage.2016.07.012},
doi = {10.1016/j.neuroimage.2016.07.012},
year = {2016},
date = {2016-01-01},
journal = {NeuroImage},
volume = {141},
pages = {52--59},
publisher = {Elsevier Inc.},
abstract = {Introduction: Nicotine and methylphenidate are putative cognitive enhancers in healthy and patient populations. Although they stimulate different neurotransmitter systems, they have been shown to enhance performance on overlapping measures of attention. So far, there has been no direct comparison of the effects of these two stimulants on behavioural performance or brain function in healthy humans. Here, we directly compare the two compounds using a well-established oculomotor biomarker in order to explore common and distinct behavioural and neural effects. Methods: Eighty-two healthy male non-smokers performed a smooth pursuit eye movement task while lying in an fMRI scanner. In a between-subjects, double-blind design, subjects either received placebo (placebo patch and capsule), nicotine (7 mg nicotine patch and placebo capsule), or methylphenidate (placebo patch and 40 mg methylphenidate capsule). Results: There were no significant drug effects on behavioural measures. At the neural level, methylphenidate elicited higher activation in left frontal eye field compared to nicotine, with an intermediate response under placebo. Discussion: The reduced activation of task-related regions under nicotine could be associated with more efficient neural processing, while increased hemodynamic response under methylphenidate is interpretable as enhanced processing of task-relevant networks. Together, these findings suggest dissociable neural effects of these putative cognitive enhancers.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Introduction: Nicotine and methylphenidate are putative cognitive enhancers in healthy and patient populations. Although they stimulate different neurotransmitter systems, they have been shown to enhance performance on overlapping measures of attention. So far, there has been no direct comparison of the effects of these two stimulants on behavioural performance or brain function in healthy humans. Here, we directly compare the two compounds using a well-established oculomotor biomarker in order to explore common and distinct behavioural and neural effects. Methods: Eighty-two healthy male non-smokers performed a smooth pursuit eye movement task while lying in an fMRI scanner. In a between-subjects, double-blind design, subjects either received placebo (placebo patch and capsule), nicotine (7 mg nicotine patch and placebo capsule), or methylphenidate (placebo patch and 40 mg methylphenidate capsule). Results: There were no significant drug effects on behavioural measures. At the neural level, methylphenidate elicited higher activation in left frontal eye field compared to nicotine, with an intermediate response under placebo. Discussion: The reduced activation of task-related regions under nicotine could be associated with more efficient neural processing, while increased hemodynamic response under methylphenidate is interpretable as enhanced processing of task-relevant networks. Together, these findings suggest dissociable neural effects of these putative cognitive enhancers. |
Jukka Pekka Kauppi; Melih Kandemir; Veli Matti Saarinen; Lotta Hirvenkari; Lauri Parkkonen; Arto Klami; Riitta Hari; Samuel Kaski Towards brain-activity-controlled information retrieval: Decoding image relevance from MEG signals Journal Article NeuroImage, 112 , pp. 288–298, 2015. Abstract | Links | BibTeX @article{Kauppi2015,
title = {Towards brain-activity-controlled information retrieval: Decoding image relevance from MEG signals},
author = {Jukka Pekka Kauppi and Melih Kandemir and Veli Matti Saarinen and Lotta Hirvenkari and Lauri Parkkonen and Arto Klami and Riitta Hari and Samuel Kaski},
url = {http://dx.doi.org/10.1016/j.neuroimage.2014.12.079},
doi = {10.1016/j.neuroimage.2014.12.079},
year = {2015},
date = {2015-01-01},
journal = {NeuroImage},
volume = {112},
pages = {288--298},
publisher = {Elsevier Inc.},
abstract = {We hypothesize that brain activity can be used to control future information retrieval systems. To this end, we conducted a feasibility study on predicting the relevance of visual objects from brain activity. We analyze both magnetoencephalographic (MEG) and gaze signals from nine subjects who were viewing image collages, a subset of which was relevant to a predetermined task. We report three findings: i) the relevance of an image a subject looks at can be decoded from MEG signals with performance significantly better than chance, ii) fusion of gaze-based and MEG-based classifiers significantly improves the prediction performance compared to using either signal alone, and iii) non-linear classification of the MEG signals using Gaussian process classifiers outperforms linear classification. These findings break new ground for building brain-activity-based interactive image retrieval systems, as well as for systems utilizing feedback both from brain activity and eye movements.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We hypothesize that brain activity can be used to control future information retrieval systems. To this end, we conducted a feasibility study on predicting the relevance of visual objects from brain activity. We analyze both magnetoencephalographic (MEG) and gaze signals from nine subjects who were viewing image collages, a subset of which was relevant to a predetermined task. We report three findings: i) the relevance of an image a subject looks at can be decoded from MEG signals with performance significantly better than chance, ii) fusion of gaze-based and MEG-based classifiers significantly improves the prediction performance compared to using either signal alone, and iii) non-linear classification of the MEG signals using Gaussian process classifiers outperforms linear classification. These findings break new ground for building brain-activity-based interactive image retrieval systems, as well as for systems utilizing feedback both from brain activity and eye movements. |
Niels A Kloosterman; Thomas Meindertsma; Arjan Hillebrand; Bob W van Dijk; Victor A F Lamme; Tobias H Donner Top-down modulation in human visual cortex predicts the stability of a perceptual illusion Journal Article Journal of Neurophysiology, 113 (4), pp. 1063–1076, 2015. Abstract | Links | BibTeX @article{Kloosterman2015,
title = {Top-down modulation in human visual cortex predicts the stability of a perceptual illusion},
author = {Niels A Kloosterman and Thomas Meindertsma and Arjan Hillebrand and Bob W van Dijk and Victor A F Lamme and Tobias H Donner},
url = {http://jn.physiology.org/lookup/doi/10.1152/jn.00338.2014},
doi = {10.1152/jn.00338.2014},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neurophysiology},
volume = {113},
number = {4},
pages = {1063--1076},
abstract = {Conscious perception sometimes fluctuates strongly, even when the sensory input is constant. For example, in motion-induced blindness (MIB), a salient visual target surrounded by a moving pattern suddenly disappears from perception, only to reappear after some variable time. Whereas such changes of perception result from fluctuations of neural activity, mounting evidence suggests that the perceptual changes, in turn, may also cause modulations of activity in several brain areas, including visual cortex. In this study, we asked whether these latter modulations might affect the subsequent dynamics of perception. We used magnetoencephalography (MEG) to measure modulations in cortical population activity during MIB. We observed a transient, retinotopically widespread modulation of beta (12-30 Hz)-frequency power over visual cortex that was closely linked to the time of subjects' behavioral report of the target disappearance. This beta modulation was a top-down signal, decoupled from both the physical stimulus properties and the motor response but contingent on the behavioral relevance of the perceptual change. Critically, the modulation amplitude predicted the duration of the subsequent target disappearance. We propose that the transformation of the perceptual change into a report triggers a top-down mechanism that stabilizes the newly selected perceptual interpretation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Conscious perception sometimes fluctuates strongly, even when the sensory input is constant. For example, in motion-induced blindness (MIB), a salient visual target surrounded by a moving pattern suddenly disappears from perception, only to reappear after some variable time. Whereas such changes of perception result from fluctuations of neural activity, mounting evidence suggests that the perceptual changes, in turn, may also cause modulations of activity in several brain areas, including visual cortex. In this study, we asked whether these latter modulations might affect the subsequent dynamics of perception. We used magnetoencephalography (MEG) to measure modulations in cortical population activity during MIB. We observed a transient, retinotopically widespread modulation of beta (12-30 Hz)-frequency power over visual cortex that was closely linked to the time of subjects' behavioral report of the target disappearance. This beta modulation was a top-down signal, decoupled from both the physical stimulus properties and the motor response but contingent on the behavioral relevance of the perceptual change. Critically, the modulation amplitude predicted the duration of the subsequent target disappearance. We propose that the transformation of the perceptual change into a report triggers a top-down mechanism that stabilizes the newly selected perceptual interpretation. |
Christian Kluge; Markus Bauer; A P Leff; Hans-jochen H -J Heinze; Raymond J Dolan; Jon Driver; Alexander Paul; Hans-jochen H -J Heinze; Raymond J Dolan; Jon Driver Plasticity of human auditory-evoked fields induced by shock conditioning and contingency reversal Journal Article Proceedings of the National Academy of Sciences, 108 (30), pp. 12545–12550, 2011. Abstract | Links | BibTeX @article{Kluge2011,
title = {Plasticity of human auditory-evoked fields induced by shock conditioning and contingency reversal},
author = {Christian Kluge and Markus Bauer and A P Leff and Hans-jochen H -J Heinze and Raymond J Dolan and Jon Driver and Alexander Paul and Hans-jochen H -J Heinze and Raymond J Dolan and Jon Driver},
url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1016124108},
doi = {10.1073/pnas.1016124108},
year = {2011},
date = {2011-01-01},
journal = {Proceedings of the National Academy of Sciences},
volume = {108},
number = {30},
pages = {12545--12550},
abstract = {We used magnetoencephalography (MEG) to assess plasticity of human auditory cortex induced by classical conditioning and contingency reversal. Participants listened to random sequences of high or low tones. A first baseline phase presented these without further associations. In phase 2, one of the frequencies (CS(+)) was paired with shock on half its occurrences, whereas the other frequency (CS(-)) was not. In phase 3, the contingency assigning CS(+) and CS(-) was reversed. Conditioned pupil dilation was observed in phase 2 but extinguished in phase 3. MEG revealed that, during phase-2 initial conditioning, the P1m, N1m, and P2m auditory components, measured from sensors over auditory temporal cortex, came to distinguish between CS(+) and CS(-). After contingency reversal in phase 3, the later P2m component rapidly reversed its selectivity (unlike the pupil response) but the earlier P1m did not, whereas N1m showed some new learning but not reversal. These results confirm plasticity of human auditory responses due to classical conditioning, but go further in revealing distinct constraints on different levels of the auditory hierarchy. The later P2m component can reverse affiliation immediately in accord with an updated expectancy after contingency reversal, whereas the earlier auditory components cannot. These findings indicate distinct cognitive and emotional influences on auditory processing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We used magnetoencephalography (MEG) to assess plasticity of human auditory cortex induced by classical conditioning and contingency reversal. Participants listened to random sequences of high or low tones. A first baseline phase presented these without further associations. In phase 2, one of the frequencies (CS(+)) was paired with shock on half its occurrences, whereas the other frequency (CS(-)) was not. In phase 3, the contingency assigning CS(+) and CS(-) was reversed. Conditioned pupil dilation was observed in phase 2 but extinguished in phase 3. MEG revealed that, during phase-2 initial conditioning, the P1m, N1m, and P2m auditory components, measured from sensors over auditory temporal cortex, came to distinguish between CS(+) and CS(-). After contingency reversal in phase 3, the later P2m component rapidly reversed its selectivity (unlike the pupil response) but the earlier P1m did not, whereas N1m showed some new learning but not reversal. These results confirm plasticity of human auditory responses due to classical conditioning, but go further in revealing distinct constraints on different levels of the auditory hierarchy. The later P2m component can reverse affiliation immediately in accord with an updated expectancy after contingency reversal, whereas the earlier auditory components cannot. These findings indicate distinct cognitive and emotional influences on auditory processing. |
Tomas Knapen; Jascha D Swisher; Frank Tong; Patrick Cavanagh Oculomotor remapping of visual information to foveal retinotopic cortex Journal Article Frontiers in Systems Neuroscience, 10 , pp. 1–12, 2016. Abstract | Links | BibTeX @article{Knapen2016a,
title = {Oculomotor remapping of visual information to foveal retinotopic cortex},
author = {Tomas Knapen and Jascha D Swisher and Frank Tong and Patrick Cavanagh},
url = {http://journal.frontiersin.org/Article/10.3389/fnsys.2016.00054/abstract},
doi = {10.3389/fnsys.2016.00054},
year = {2016},
date = {2016-01-01},
journal = {Frontiers in Systems Neuroscience},
volume = {10},
pages = {1--12},
abstract = {Our eyes continually jump around the visual scene to bring the high-resolution, central part of our vision onto objects of interest. We are oblivious to these abrupt shifts, perceiving the visual world to appear reassuringly stable. A process called remapping has been proposed to mediate this perceptual stability for attended objects by shifting their retinotopic representation to compensate for the effects of the upcoming eye movement. In everyday vision, observers make goal-directed eye movements towards items of interest bringing them to the fovea and, for these items, the remapped activity should impinge on foveal regions of the retinotopic maps in visual cortex. Previous research has focused instead on remapping for targets that were not saccade goals, where activity is remapped to a new peripheral location rather than to the foveal representation. We used functional MRI and a phase-encoding design to investigate remapping of spatial patterns of activity towards the fovea/parafovea for saccade targets that were removed prior to completion of the eye movement. We found strong evidence of foveal remapping in retinotopic visual areas, which failed to occur when observers merely attended to the same peripheral target without making eye movements toward it. Significantly, the spatial profile of the remapped response matched the orientation and size of the saccade target, and was appropriately scaled to reflect the retinal extent of the stimulus had it been foveated. We conclude that this remapping of spatially structured information to the fovea may serve as an important mechanism to support our world-centered sense of location across goal-directed eye movements under natural viewing conditions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Our eyes continually jump around the visual scene to bring the high-resolution, central part of our vision onto objects of interest. We are oblivious to these abrupt shifts, perceiving the visual world to appear reassuringly stable. A process called remapping has been proposed to mediate this perceptual stability for attended objects by shifting their retinotopic representation to compensate for the effects of the upcoming eye movement. In everyday vision, observers make goal-directed eye movements towards items of interest bringing them to the fovea and, for these items, the remapped activity should impinge on foveal regions of the retinotopic maps in visual cortex. Previous research has focused instead on remapping for targets that were not saccade goals, where activity is remapped to a new peripheral location rather than to the foveal representation. We used functional MRI and a phase-encoding design to investigate remapping of spatial patterns of activity towards the fovea/parafovea for saccade targets that were removed prior to completion of the eye movement. We found strong evidence of foveal remapping in retinotopic visual areas, which failed to occur when observers merely attended to the same peripheral target without making eye movements toward it. Significantly, the spatial profile of the remapped response matched the orientation and size of the saccade target, and was appropriately scaled to reflect the retinal extent of the stimulus had it been foveated. We conclude that this remapping of spatially structured information to the fovea may serve as an important mechanism to support our world-centered sense of location across goal-directed eye movements under natural viewing conditions. |
Zoe Kourtzi; Lisa R Betts; Pegah Sarkheil; Andrew E Welchman Distributed neural plasticity for shape learning in the human visual cortex Journal Article PLoS Biology, 3 (7), pp. 1317–1327, 2005. Abstract | Links | BibTeX @article{Kourtzi2005,
title = {Distributed neural plasticity for shape learning in the human visual cortex},
author = {Zoe Kourtzi and Lisa R Betts and Pegah Sarkheil and Andrew E Welchman},
doi = {10.1371/journal.pbio.0030204},
year = {2005},
date = {2005-01-01},
journal = {PLoS Biology},
volume = {3},
number = {7},
pages = {1317--1327},
abstract = {Expertise in recognizing objects in cluttered scenes is a critical skill for our interactions in complex environments and is thought to develop with learning. However, the neural implementation of object learning across stages of visual analysis in the human brain remains largely unknown. Using combined psychophysics and functional magnetic resonance imaging (fMRI), we show a link between shape-specific learning in cluttered scenes and distributed neuronal plasticity in the human visual cortex. We report stronger fMRI responses for trained than untrained shapes across early and higher visual areas when observers learned to detect low-salience shapes in noisy backgrounds. However, training with high-salience pop-out targets resulted in lower fMRI responses for trained than untrained shapes in higher occipitotemporal areas. These findings suggest that learning of camouflaged shapes is mediated by increasing neural sensitivity across visual areas to bolster target segmentation and feature integration. In contrast, learning of prominent pop-out shapes is mediated by associations at higher occipitotemporal areas that support sparser coding of the critical features for target recognition. We propose that the human brain learns novel objects in complex scenes by reorganizing shape processing across visual areas, while taking advantage of natural image correlations that determine the distinctiveness of target shapes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Expertise in recognizing objects in cluttered scenes is a critical skill for our interactions in complex environments and is thought to develop with learning. However, the neural implementation of object learning across stages of visual analysis in the human brain remains largely unknown. Using combined psychophysics and functional magnetic resonance imaging (fMRI), we show a link between shape-specific learning in cluttered scenes and distributed neuronal plasticity in the human visual cortex. We report stronger fMRI responses for trained than untrained shapes across early and higher visual areas when observers learned to detect low-salience shapes in noisy backgrounds. However, training with high-salience pop-out targets resulted in lower fMRI responses for trained than untrained shapes in higher occipitotemporal areas. These findings suggest that learning of camouflaged shapes is mediated by increasing neural sensitivity across visual areas to bolster target segmentation and feature integration. In contrast, learning of prominent pop-out shapes is mediated by associations at higher occipitotemporal areas that support sparser coding of the critical features for target recognition. We propose that the human brain learns novel objects in complex scenes by reorganizing shape processing across visual areas, while taking advantage of natural image correlations that determine the distinctiveness of target shapes. |
