Functional connectivity of ventral temporal cortex reveals category-specificity in medial parietal areas

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.

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Multivoxel Neural Reinforcement Changes Resting-State Functional Connectivity Within the Threat Regulation Network

10.1101/2020.04.03.021956 ◽

2020 ◽

Cited By ~ 1

Author(s):

Vincent Taschereau-Dumouchel ◽

Toshinori Chiba ◽

Ai Koizumi ◽

Mitsuo Kawato ◽

Hakwan Lau

Keyword(s):

Functional Connectivity ◽

Resting State ◽

Temporal Cortex ◽

Physiological Reactivity ◽

Resting State Functional Connectivity ◽

Double Blind ◽

Brain Responses ◽

Regulation Network ◽

Before And After ◽

Ventral Temporal Cortex

AbstractUsing neural reinforcement, participants can be trained to pair a reward with the activation of specific multivoxel patterns in their brains. In a double-blind placebo-controlled experiment, we previously showed that this intervention can decrease the physiological reactivity associated with naturally feared animals. However, the mechanisms behind the effect remain incompletely understood and its usefulness for treatment remains unclear. If the intervention fundamentally changed the brain responses, we might expect to observe relatively stable changes in the functional connectivity within the threat regulation network. To evaluate this possibility, we conducted functional magnetic resonance imaging (fMRI) sessions while subjects were at rest, before and after neural reinforcement, and quantified the changes in resting-state functional connectivity accordingly. Our results indicate that neural reinforcement increased the connectivity of prefrontal regulatory regions with the amygdala and the ventral temporal cortex (where the visual representations of phobic targets are). Surprisingly, we found no evidence of Hebbian-like learning during neural reinforcement, contrary to what one may expect based on previous neurofeedback studies. These results suggest that multivoxel neural reinforcement, also known as decoded neurofeedback (DecNef), may operate via unique mechanisms, distinct from those involved in conventional neurofeedback.

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

eLife ◽

10.7554/elife.47391 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 14

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.

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Stereotypes bias face perception via orbitofrontal–fusiform cortical interaction

Social Cognitive and Affective Neuroscience ◽

10.1093/scan/nsaa165 ◽

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.

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