scholarly journals Flexible top-down modulation in human ventral temporal cortex

2018 ◽  
Author(s):  
Ruyuan Zhang ◽  
Kendrick Kay
Keyword(s):  
Cognitive Processes ◽  
Cognitive Task ◽  
Temporal Cortex ◽  
Independent Experiment ◽  
Perceptual Task ◽  
Top Down ◽  
Quantitative Understanding ◽  
Conventional Models ◽  
Ventral Temporal Cortex ◽  
Contrast Response

ABSTRACTVisual neuroscientists have long characterized attention as inducing a scaling or additive effect on fixed parametric functions describing neural responses (e.g., contrast response functions). Here, we instead propose that top-down effects are more complex and manifest in ways that depend not only on attention but also other cognitive processes involved in executing a task. To substantiate this theory, we analyze fMRI responses in human ventral temporal cortex (VTC) in a study where stimulus eccentricity and cognitive task are varied. We find that as stimuli are presented farther into the periphery, bottom-up stimulus-driven responses decline but top-down attentional enhancement increases substantially. This disproportionate enhancement of weak responses cannot be easily explained by conventional models of attention. Furthermore, we find that attentional effects depend on the specific cognitive task performed by the subject, indicating the influence of additional cognitive processes other than attention (e.g., decision-making). The effects we observe replicate in an independent experiment from the same study, and also generalize to a separate study involving different stimulus manipulations (contrast and phase coherence). Our results suggest that a quantitative understanding of top-down modulation requires more nuanced and more precise characterization of multiple cognitive factors involved in completing a perceptual task.

scholarly journals Bottom-up and top-down computations in word- and face-selective cortex

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Kendrick N Kay ◽  
Jason D Yeatman
Keyword(s):  
Face Recognition ◽  
Cognitive Task ◽  
Temporal Cortex ◽  
Intraparietal Sulcus ◽  
Neural Processing ◽  
Top Down ◽  
Cognitive Demands ◽  
Bottom Up ◽  
Stimulus Match ◽  
Ventral Temporal Cortex

The ability to read a page of text or recognize a person's face depends on category-selective visual regions in ventral temporal cortex (VTC). To understand how these regions mediate word and face recognition, it is necessary to characterize how stimuli are represented and how this representation is used in the execution of a cognitive task. Here, we show that the response of a category-selective region in VTC can be computed as the degree to which the low-level properties of the stimulus match a category template. Moreover, we show that during execution of a task, the bottom-up representation is scaled by the intraparietal sulcus (IPS), and that the level of IPS engagement reflects the cognitive demands of the task. These results provide an account of neural processing in VTC in the form of a model that addresses both bottom-up and top-down effects and quantitatively predicts VTC responses.

scholarly journals Bottom-up and top-down computations in high-level visual cortex

2016 ◽  
Author(s):  
Kendrick N. Kay ◽  
Jason D. Yeatman
Keyword(s):  
Cognitive Task ◽  
Temporal Cortex ◽  
Intraparietal Sulcus ◽  
Neural Processing ◽  
Top Down ◽  
Cognitive Demands ◽  
Bottom Up ◽  
Stimulus Match ◽  
Ventral Temporal Cortex ◽  
High Level

SummaryThe ability to read a page of text or recognize a person’s face depends on category-selective visual regions in ventral temporal cortex (VTC). To understand how these regions mediate word and face recognition, it is necessary to characterize how stimuli are represented and how this representation is used in the execution of a cognitive task. Here, we show that the response of a category-selective region in VTC can be computed as the degree to which the low-level properties of the stimulus match a category template. Moreover, we show that during execution of a task, the bottom-up representation is scaled by the intraparietal sulcus (IPS), and that the level of IPS engagement reflects the cognitive demands of the task. These results provide a unifying account of neural processing in VTC in the form of a model that addresses both bottom-up and top-down effects and quantitatively predicts VTC responses.

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 Distinct subdivisions of human medial parietal cortex are recruited differentially for memory recall of places and people

2019 ◽  
Author(s):  
Edward H Silson ◽  
Adam Steel ◽  
Alexis Kidder ◽  
Adrian W Gilmore ◽  
Chris I Baker
Keyword(s):  
Parietal Cortex ◽  
Cognitive Processes ◽  
Default Mode Network ◽  
Temporal Cortex ◽  
Visual Presentation ◽  
Memory Recall ◽  
Default Mode ◽  
Scene Processing ◽  
People First ◽  
Ventral Temporal Cortex

AbstractHuman medial parietal cortex (MPC) is implicated in multiple cognitive processes including memory recall, visual scene processing and navigation. It is also considered a core component of the default mode network. Here, we combine fMRI data across three independent experiments to demonstrate distinct subdivisions of MPC that are selectively recruited during memory recall of either specific places or specific people. First, distinct regions of MPC were identified on the basis of differential functional connectivity with medial and lateral regions of anterior ventral temporal cortex (VTC). Second, these same medial regions exhibited differential responses to the visual presentation of different stimulus categories, with clear preferences for scenes and faces, respectively. Third, and most critically, these regions were selectively recruited during either place or people memory recall. These subdivisions also showed a striking relationship with ventral and dorsal divisions of the default mode network. Taken together, these data reveal distinct subdivisions within MPC for the recall of places and people and moreover, suggest that the organizing principle defining the medial-lateral axis of VTC is reflected in MPC, but in the context of memory recall.

scholarly journals Flexible top-down modulation in human ventral temporal cortex

NeuroImage ◽  
2020 ◽  
Vol 218 ◽  
pp. 116964 ◽  
Author(s):  
Ru-Yuan Zhang ◽  
Kendrick Kay
Keyword(s):  
Temporal Cortex ◽  
Top Down ◽  
Ventral Temporal Cortex

scholarly journals Distinct subdivisions of human medial parietal cortex support recollection of people and places

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Edward H Silson ◽  
Adam Steel ◽  
Alexis Kidder ◽  
Adrian W Gilmore ◽  
Chris I Baker
Keyword(s):  
Functional Connectivity ◽  
Parietal Cortex ◽  
Cognitive Processes ◽  
Temporal Cortex ◽  
Visual Presentation ◽  
Memory Recall ◽  
Core Component ◽  
Scene Processing ◽  
Ventral Temporal Cortex ◽  
Lateral Axis

Human medial parietal cortex (MPC) is implicated in multiple cognitive processes including memory recall, visual scene processing and navigation, and is a core component of the default mode network. Here, we demonstrate distinct subdivisions of MPC that are selectively recruited during memory recall of either specific people or places. First, distinct regions of MPC exhibited differential functional connectivity with medial and lateral regions of ventral temporal cortex (VTC). Second, these same medial regions showed selective, but negative, responses to the visual presentation of different stimulus categories, with clear preferences for scenes and faces. Finally, and most critically, these regions were differentially recruited during memory recall of either people or places with a strong familiarity advantage. Taken together, these data suggest that the organizing principle defining the medial-lateral axis of VTC is reflected in MPC, but in the context of memory recall.

scholarly journals Stereotypes bias face perception via orbitofrontal–fusiform cortical interaction

2020 ◽  
Author(s):  
Benjamin O Barnett ◽  
Jeffrey A Brooks ◽  
Jonathan B Freeman
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Connectivity ◽  
Orbitofrontal Cortex ◽  
Temporal Cortex ◽  
Backward Masking ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Top Down ◽  
Ventral Temporal Cortex

Abstract Previous research has shown that social-conceptual associations, such as stereotypes, can influence the visual representation of faces and neural pattern responses in ventral temporal cortex (VTC) regions, such as the fusiform gyrus (FG). Current models suggest that this social-conceptual impact requires medial orbitofrontal cortex (mOFC) feedback signals during perception. Backward masking can disrupt such signals, as it is a technique known to reduce functional connectivity between VTC regions and regions outside VTC. During functional magnetic resonance imaging (fMRI), subjects passively viewed masked and unmasked faces, and following the scan, perceptual biases and stereotypical associations were assessed. Multi-voxel representations of faces across the VTC, and in the FG and mOFC, reflected stereotypically biased perceptions when faces were unmasked, but this effect was abolished when faces were masked. However, the VTC still retained the ability to process masked faces and was sensitive to their categorical distinctions. Functional connectivity analyses confirmed that masking disrupted mOFC–FG connectivity, which predicted a reduced impact of stereotypical associations in the FG. Taken together, our findings suggest that the biasing of face representations in line with stereotypical associations does not arise from intrinsic processing within the VTC and FG alone, but instead it depends in part on top-down feedback from the mOFC during perception.

Sign in / Sign up

Export Citation Format

Share Document