Concurrent category-selective neural activity across the ventral occipito-temporal cortex supports a non-hierarchical view of human visual recognition.

Abstract

Visual recognition is a fundamental human brain function, supported by a network of regions in the ventral occipito-temporal cortex (VOTC). This network is thought to be organized hierarchically, with definite processing stages increasing in invariance and time-course from posterior to anterior cortical regions. Here, we provide a stringent test of this view by measuring category-selective neural activity to natural images of faces across the VOTC with electrophysiological intracerebral recordings in a large human sample (N=140; >11,000 recording sites). Face-selective high frequency broadband (30-160 Hz) neural activity is distributed across the VOTC, with right-hemispheric dominance and regional peaks of activity. Crucially, while a progressive increase in degree of category-selectivity is found along the postero-anterior axis, neural activity occurs largely concurrently (~100 ms onset - ~450 ms offset) across all VOTC regions. These observations challenge the standard hierarchical view of neural organization of visual object recognition in the human association cortex, supporting alternative models of this key brain function.