Category-Selectivity in Human Visual Cortex Follows Cortical Topology: A Grouped icEEG Study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Electrophysiology

Background:

• Higher-order visual cortex regions are organized around anatomical landmarks like the mid-fusiform sulcus (MFS) and lateral occipital sulcus (LOS).
• Previous neuroimaging studies suggest a topological organization of category-selectivity, but direct electrophysiological evidence is limited.

Purpose of the Study:

• To create precise structure-function maps using direct neural signals from intracranial EEG (icEEG).
• To investigate the topology of category-selectivity for faces, animate non-faces, places, tools, and words in the ventral temporal cortex (VTC) and lateral occipital cortex (LOC).

Main Methods:

• Collected icEEG recordings from 26 human participants with subdural electrodes.
• Employed a surface-based approach for grouped icEEG analysis to address challenges of sparse electrode coverage and anatomical variability.
• Assessed category-selectivity using correlational and linear mixed effects analyses for five stimulus classes.

Main Results:

• In the LOC, selectivity for living (faces, animate non-faces) and non-living (places, tools) stimuli followed a ventral-to-dorsal axis along the LOS.
• In the VTC, selectivity for living and non-living stimuli was organized along a latero-medial axis of the MFS.
• Written word selectivity was precisely localized to the intersection of the left MFS and the occipito-temporal sulcus.

Conclusions:

• Direct electrophysiological evidence confirms a topological structuring of functional representations in higher-order visual cortex.
• Findings elucidate the precise neural basis of visual category representation and localization within specific cortical sulci.