scholarly journals A probabilistic functional atlas of human occipito-temporal visual cortex

2020 ◽  
Author(s):  
Mona Rosenke ◽  
Rick van Hoof ◽  
Job van den Hurk ◽  
Kalanit Grill-Spector ◽  
Rainer Goebel
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Large Body ◽  
Temporal Cortex ◽  
Region Of Interest ◽  
Brain Regions ◽  
Functional Region ◽  
Independent Dataset ◽  
Accurate Localization ◽  
Ventral Temporal Cortex

AbstractHuman visual cortex contains many retinotopic and category-specific regions. These brain regions have been the focus of a large body of functional MRI research, significantly expanding our understanding of visual processing. As studying these regions requires accurate localization of their cortical location, researchers perform functional localizer scans to identify these regions in each individual. However, it not always possible to conduct these localizer scans. Here, we developed and validated a functional region of interest atlas of early visual and category-selective regions in human ventral and lateral occipito-temporal cortex. Results show that for the majority of fROIs, cortex-based alignment results in lower between-subject variability compared to nonlinear volumetric alignment. Furthermore, we demonstrate that (1) the atlas accurately predicts the location of an independent dataset of ventral temporal cortex ROIs and other atlases of place-selectivity, motion-selectivity, and retinotopy. Next, (2) we show that the majority of voxel within our atlas are responding mostly to the labelled category in a left-out subject cross-validation, demonstrating the utility of this atlas. The functional atlas is publicly available (download.brainvoyager.com/data/visfAtlas.zip) and can help identify the location of these regions in healthy subjects as well as populations (e.g. blind people, infants) in which functional localizers cannot be run.

scholarly journals A Probabilistic Functional Atlas of Human Occipito-Temporal Visual Cortex

2020 ◽  
Vol 31 (1) ◽  
pp. 603-619 ◽  
Author(s):  
Mona Rosenke ◽  
Rick van Hoof ◽  
Job van den Hurk ◽  
Kalanit Grill-Spector ◽  
Rainer Goebel
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Large Body ◽  
Temporal Cortex ◽  
Region Of Interest ◽  
Brain Regions ◽  
Functional Region ◽  
Accurate Localization ◽  
Imaging Research ◽  
Ventral Temporal Cortex

Abstract Human visual cortex contains many retinotopic and category-specific regions. These brain regions have been the focus of a large body of functional magnetic resonance imaging research, significantly expanding our understanding of visual processing. As studying these regions requires accurate localization of their cortical location, researchers perform functional localizer scans to identify these regions in each individual. However, it is not always possible to conduct these localizer scans. Here, we developed and validated a functional region of interest (ROI) atlas of early visual and category-selective regions in human ventral and lateral occipito-temporal cortex. Results show that for the majority of functionally defined ROIs, cortex-based alignment results in lower between-subject variability compared to nonlinear volumetric alignment. Furthermore, we demonstrate that 1) the atlas accurately predicts the location of an independent dataset of ventral temporal cortex ROIs and other atlases of place selectivity, motion selectivity, and retinotopy. Next, 2) we show that the majority of voxel within our atlas is responding mostly to the labeled category in a left-out subject cross-validation, demonstrating the utility of this atlas. The functional atlas is publicly available (download.brainvoyager.com/data/visfAtlas.zip) and can help identify the location of these regions in healthy subjects as well as populations (e.g., blind people, infants) in which functional localizers cannot be run.

scholarly journals Representational Connectivity Analysis: Identifying Networks of Shared Changes in Representational Strength through Jackknife Resampling

2020 ◽  
Author(s):  
Marc N. Coutanche ◽  
Essang Akpan ◽  
Rae R. Buckser
Keyword(s):  
Visual Processing ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Statistical Technique ◽  
Second Order ◽  
Seed Region ◽  
Connectivity Analysis ◽  
Representational Space ◽  
Classic Form ◽  
Ventral Temporal Cortex

AbstractThe structure of information in the brain is crucial to cognitive function. The representational space of a brain region can be identified through Representational Similarity Analysis (RSA) applied to functional magnetic resonance imaging (fMRI) data. In its classic form, RSA collapses the time-series of each condition, eliminating fluctuations in similarity over time. We propose a method for identifying representational connectivity (RC) networks, which share fluctuations in representational strength, in an analogous manner to functional connectivity (FC), which tracks fluctuations in BOLD signal, and informational connectivity, which tracks fluctuations in pattern discriminability. We utilize jackknife resampling, a statistical technique in which observations are removed in turn to determine their influence. We applied the jackknife technique to an existing fMRI dataset collected as participants viewed videos of animals (Nastase et al., 2017). We used ventral temporal cortex (VT) as a seed region, and compared the resulting network to a second-order RSA, in which brain regions’ representational spaces are compared, and to the network identified through FC. The novel representational connectivity analysis identified a network comprising regions associated with lower-level visual processing, spatial cognition, perceptual-motor integration, and visual attention, indicating that these regions shared fluctuations in representational similarity strength with VT. RC, second-order RSA and FC identified areas unique to each method, indicating that analyzing shared fluctuations in the strength of representational similarity reveals previously undetectable networks of regions. The RC analysis thus offers a new way to understand representational similarity at the network level.

scholarly journals The Human Intraparietal Sulcus Modulates Task-Evoked Functional Connectivity

2019 ◽  
Vol 30 (3) ◽  
pp. 875-887
Author(s):  
Kai Hwang ◽  
James M Shine ◽  
Dillan Cellier ◽  
Mark D’Esposito
Keyword(s):  
Functional Connectivity ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Intraparietal Sulcus ◽  
Top Down ◽  
Adaptive Communication ◽  
Wide Range ◽  
Functional Connectivity Strength ◽  
Ventral Temporal Cortex ◽  
Cortical Regions

Abstract Past studies have demonstrated that flexible interactions between brain regions support a wide range of goal-directed behaviors. However, the neural mechanisms that underlie adaptive communication between brain regions are not well understood. In this study, we combined theta-burst transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging to investigate the sources of top-down biasing signals that influence task-evoked functional connectivity. Subjects viewed sequences of images of faces and buildings and were required to detect repetitions (2-back vs. 1-back) of the attended stimuli category (faces or buildings). We found that functional connectivity between ventral temporal cortex and the primary visual cortex (VC) increased during processing of task-relevant stimuli, especially during higher memory loads. Furthermore, the strength of functional connectivity was greater for correct trials. Increases in task-evoked functional connectivity strength were correlated with increases in activity in multiple frontal, parietal, and subcortical (caudate and thalamus) regions. Finally, we found that TMS to superior intraparietal sulcus (IPS), but not to primary somatosensory cortex, decreased task-specific modulation in connectivity patterns between the primary VC and the parahippocampal place area. These findings demonstrate that the human IPS is a source of top-down biasing signals that modulate task-evoked functional connectivity among task-relevant cortical regions.

scholarly journals Brain Mechanisms of Arithmetic: A Crucial Role for Ventral Temporal Cortex

2018 ◽  
Vol 30 (12) ◽  
pp. 1757-1772 ◽  
Author(s):  
Pedro Pinheiro-Chagas ◽  
Amy Daitch ◽  
Josef Parvizi ◽  
Stanislas Dehaene
Keyword(s):  
Numerical Cognition ◽  
Parietal Lobe ◽  
Temporal Cortex ◽  
Classical Problem ◽  
Brain Regions ◽  
Inferior Temporal Cortex ◽  
Problem Size ◽  
Ventral Temporal Cortex ◽  
Intracranial Electroencephalography ◽  
Problem Size Effect

Elementary arithmetic requires a complex interplay between several brain regions. The classical view, arising from fMRI, is that the intraparietal sulcus (IPS) and the superior parietal lobe (SPL) are the main hubs for arithmetic calculations. However, recent studies using intracranial electroencephalography have discovered a specific site, within the posterior inferior temporal cortex (pITG), that activates during visual perception of numerals, with widespread adjacent responses when numerals are used in calculation. Here, we reexamined the contribution of the IPS, SPL, and pITG to arithmetic by recording intracranial electroencephalography signals while participants solved addition problems. Behavioral results showed a classical problem size effect: RTs increased with the size of the operands. We then examined how high-frequency broadband (HFB) activity is modulated by problem size. As expected from previous fMRI findings, we showed that the total HFB activity in IPS and SPL sites increased with problem size. More surprisingly, pITG sites showed an initial burst of HFB activity that decreased as the operands got larger, yet with a constant integral over the whole trial, thus making these signals invisible to slow fMRI. Although parietal sites appear to have a more sustained function in arithmetic computations, the pITG may have a role of early identification of the problem difficulty, beyond merely digit recognition. Our results ask for a reevaluation of the current models of numerical cognition and reveal that the ventral temporal cortex contains regions specifically engaged in mathematical processing.

Extensive individual differences of category information in ventral temporal cortex in the congenitally blind

2020 ◽  
Author(s):  
M. Rosenke ◽  
J. Van den Hurk ◽  
E. Margalit ◽  
H. P. Op de Beeck ◽  
K. Grill-Spector ◽  
...  
Keyword(s):  
Individual Differences ◽  
Visual Stimuli ◽  
Large Body ◽  
Temporal Cortex ◽  
Group Level ◽  
Homogeneous Population ◽  
Congenitally Blind ◽  
Functional Representations ◽  
Group Members ◽  
Ventral Temporal Cortex

AbstractHuman ventral temporal cortex (VTC) is a cortical expanse that performs different functions and computations, but is especially critical for visual categorization. Nevertheless, accumulating evidence shows that category-selective regions persist in VTC in the absence of visual experience – for example, in congenitally blind (CB) participants. Despite this evidence, a large body of previous work comparing functional representations in VTC between sighted and CB participants performed univariate analyses at the group level, which assume a homogeneous population – an assumption that has not been formally tested until the present study. Specifically, using fMRI in CB and sighted participants (male and female), we empirically show that at the group level, distributed category representations in VTC are more reliable in the sighted (when viewing visual stimuli) compared to the CB (when hearing auditorily-substituted visual stimuli). Despite these group differences, there is extensive heterogeneity in VTC category representations in the CB to the point that VTC category representations in a subset of CB participants (some who were born without eyes, but not all) are more similar to sighted individuals compared to other CB participants. Together, our findings support a novel idea that driving factors contributing to the formation of VTC category representations in the blind are subject-specific, which complements factors that may generalize across group members. More broadly, the present findings caution conclusions of homogeneity across subjects within a group when performing group neuroimaging analyses without explicitly quantifying individual differences.

scholarly journals A neurocognitive investigation of the impact of socializing with a robot on empathy for pain

2019 ◽  
Vol 374 (1771) ◽  
pp. 20180034 ◽  
Author(s):  
Emily S. Cross ◽  
Katie A. Riddoch ◽  
Jaydan Pratts ◽  
Simon Titone ◽  
Bishakha Chaudhury ◽  
...  
Keyword(s):  
Social Relationships ◽  
Functional Neuroimaging ◽  
Region Of Interest ◽  
Brain Regions ◽  
Social Robot ◽  
Human Robot Interaction ◽  
Functional Region ◽  
Repetition Suppression ◽  
Empathy For Pain ◽  
The Impact

To what extent can humans form social relationships with robots? In the present study, we combined functional neuroimaging with a robot socializing intervention to probe the flexibility of empathy, a core component of social relationships, towards robots. Twenty-six individuals underwent identical fMRI sessions before and after being issued a social robot to take home and interact with over the course of a week. While undergoing fMRI, participants observed videos of a human actor or a robot experiencing pain or pleasure in response to electrical stimulation. Repetition suppression of activity in the pain network, a collection of brain regions associated with empathy and emotional responding, was measured to test whether socializing with a social robot leads to greater overlap in neural mechanisms when observing human and robotic agents experiencing pain or pleasure. In contrast to our hypothesis, functional region-of-interest analyses revealed no change in neural overlap for agents after the socializing intervention. Similarly, no increase in activation when observing a robot experiencing pain emerged post-socializing. Whole-brain analysis showed that, before the socializing intervention, superior parietal and early visual regions are sensitive to novel agents, while after socializing, medial temporal regions show agent sensitivity. A region of the inferior parietal lobule was sensitive to novel emotions, but only during the pre-socializing scan session. Together, these findings suggest that a short socialization intervention with a social robot does not lead to discernible differences in empathy towards the robot, as measured by behavioural or brain responses. We discuss the extent to which long-term socialization with robots might shape social cognitive processes and ultimately our relationships with these machines. This article is part of the theme issue ‘From social brains to social robots: applying neurocognitive insights to human–robot interaction’.

scholarly journals Disentangling Representations of Object Shape and Object Category in Human Visual Cortex: The Animate–Inanimate Distinction

2016 ◽  
Vol 28 (5) ◽  
pp. 680-692 ◽  
Author(s):  
Daria Proklova ◽  
Daniel Kaiser ◽  
Marius V. Peelen
Keyword(s):  
Visual Cortex ◽  
Activity Patterns ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Visual Object ◽  
Object Category ◽  
Human Visual Cortex ◽  
Object Properties ◽  
Occipitotemporal Cortex ◽  
Visual Properties

Objects belonging to different categories evoke reliably different fMRI activity patterns in human occipitotemporal cortex, with the most prominent distinction being that between animate and inanimate objects. An unresolved question is whether these categorical distinctions reflect category-associated visual properties of objects or whether they genuinely reflect object category. Here, we addressed this question by measuring fMRI responses to animate and inanimate objects that were closely matched for shape and low-level visual features. Univariate contrasts revealed animate- and inanimate-preferring regions in ventral and lateral temporal cortex even for individually matched object pairs (e.g., snake–rope). Using representational similarity analysis, we mapped out brain regions in which the pairwise dissimilarity of multivoxel activity patterns (neural dissimilarity) was predicted by the objects' pairwise visual dissimilarity and/or their categorical dissimilarity. Visual dissimilarity was measured as the time it took participants to find a unique target among identical distractors in three visual search experiments, where we separately quantified overall dissimilarity, outline dissimilarity, and texture dissimilarity. All three visual dissimilarity structures predicted neural dissimilarity in regions of visual cortex. Interestingly, these analyses revealed several clusters in which categorical dissimilarity predicted neural dissimilarity after regressing out visual dissimilarity. Together, these results suggest that the animate–inanimate organization of human visual cortex is not fully explained by differences in the characteristic shape or texture properties of animals and inanimate objects. Instead, representations of visual object properties and object category may coexist in more anterior parts of the visual system.

scholarly journals Color signals through dorsal and ventral visual pathways

2013 ◽  
Vol 31 (2) ◽  
pp. 197-209 ◽  
Author(s):  
BEVIL R. CONWAY
Keyword(s):  
Visual Processing ◽  
Color Space ◽  
Temporal Cortex ◽  
Color Perception ◽  
Original Data ◽  
Brain Regions ◽  
Neural Representation ◽  
Inferior Temporal Cortex ◽  
Extrastriate Cortex ◽  
Chromatic Contrast

AbstractExplanations for color phenomena are often sought in the retina, lateral geniculate nucleus, and V1, yet it is becoming increasingly clear that a complete account will take us further along the visual-processing pathway. Working out which areas are involved is not trivial. Responses to S-cone activation are often assumed to indicate that an area or neuron is involved in color perception. However, work tracing S-cone signals into extrastriate cortex has challenged this assumption: S-cone responses have been found in brain regions, such as the middle temporal (MT) motion area, not thought to play a major role in color perception. Here, we review the processing of S-cone signals across cortex and present original data on S-cone responses measured with fMRI in alert macaque, focusing on one area in which S-cone signals seem likely to contribute to color (V4/posterior inferior temporal cortex) and on one area in which S signals are unlikely to play a role in color (MT). We advance a hypothesis that the S-cone signals in color-computing areas are required to achieve a balanced neural representation of perceptual color space, whereas those in noncolor-areas provide a cue to illumination (not luminance) and confer sensitivity to the chromatic contrast generated by natural daylight (shadows, illuminated by ambient sky, surrounded by direct sunlight). This sensitivity would facilitate the extraction of shape-from-shadow signals to benefit global scene analysis and motion perception.

scholarly journals Reduced visual and frontal cortex activation during visual working memory in grapheme-colour synaesthetes relative to young and older adults

2018 ◽  
Author(s):  
Gaby Pfeifer ◽  
Jamie Ward ◽  
Natasha Sigala
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Temporal Cortex ◽  
Region Of Interest ◽  
Inferior Temporal Cortex ◽  
Long Term Memory ◽  
Sensory Recruitment ◽  
Recruitment Model

AbstractThe sensory recruitment model envisages visual working memory (VWM) as an emergent property that is encoded and maintained in sensory (visual) regions. The model implies that enhanced sensory-perceptual functions, as in synaesthesia, entail a dedicated VWM-system, showing reduced visual cortex activity as a result of neural specificity. By contrast, sensory-perceptual decline, as in old age, is expected to show enhanced visual cortex activity as a result of neural broadening. To test this model, young grapheme-colour synaesthetes, older adults and young controls engaged in a delayed pair-associative retrieval and a delayed matching-to-sample task, consisting of achromatic fractal stimuli that do not induce synaesthesia. While a previous analysis of this dataset (Pfeifer et al., 2016) has focused on cued retrieval and recognition of pair-associates (i.e. long-term memory), the current study focuses on visual working memory and considers, for the first time, the crucial delay period in which no visual stimuli are present, but working memory processes are engaged. Participants were trained to criterion and demonstrated comparable behavioural performance on VWM tasks. Whole-brain and region-of-interest-analyses revealed significantly lower activity in synaesthetes’ middle frontal gyrus and visual regions (cuneus, inferior temporal cortex) respectively, suggesting greater neural efficiency relative to young and older adults in both tasks. The results support the sensory recruitment model and can explain age and individual WM-differences based on neural specificity in visual cortex.

scholarly journals A neurocognitive investigation of the impact of socialising with a robot on empathy for pain

2018 ◽  
Author(s):  
Emily S. Cross ◽  
Katie A. Riddoch ◽  
Jaydan Pratts ◽  
Simon Titone ◽  
Bishakha Chaudhury ◽  
...  
Keyword(s):  
Social Relationships ◽  
Functional Neuroimaging ◽  
Region Of Interest ◽  
Brain Regions ◽  
Social Robot ◽  
Functional Region ◽  
Repetition Suppression ◽  
Before And After ◽  
Empathy For Pain ◽  
The Impact

To what extent can humans form social relationships with robots? In the present study, we combined functional neuroimaging with a robot socialising intervention to probe the flexibility of empathy, a core component of social relationships, toward robots. Twenty-six individuals underwent identical fMRI sessions before and after being issued a social robot to take home and interact with over the course of a week. While undergoing fMRI, participants observed videos of a human actor or a robot experiencing pain or pleasure in response to electrical stimulation. Repetition suppression of activity in the pain network, a collection of brain regions associated with empathy and emotional responding, was measured to test whether socialising with a social robot leads to greater overlap in neural mechanisms when observing human and robotic agents experiencing pain or pleasure. In contrast to our hypothesis, functional region-of-interest analyses revealed no change in neural overlap for agents after the socialising intervention. Similarly, no increase in activation when observing a robot experiencing pain emerged post-socialising. Whole-brain analysis showed that, before the socialising intervention, superior parietal and early visual regions are sensitive to novel agents, while after socialising, medial temporal regions show agent sensitivity. A region of the inferior parietal lobule was sensitive to novel emotions, but only during the pre-socialising scan session. Together, these findings suggest that a short socialisation intervention with a social robot does not lead to discernible differences in empathy toward the robot, as measured by behavioural or brain responses. We discuss the extent to which longer term socialisation with robots might shape social cognitive processes and ultimately our relationships with these machines.

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