The functional organization of high-level visual cortex determines the representation of complex visual stimuli

Abstract

A hallmark of high-level visual cortex is its functional organization of neighboring clusters of neurons that are selective to single categories such as faces, bodies and objects. However, visual scenes are typically composed of multiple categories. How does category-selective cortex represent such complex stimuli? According to a normalization mechanism, the response of a single neuron to multiple stimuli is normalized by the response of its neighboring neurons (normalization pool). Here we show that category-selectivity, measured with fMRI, can provide an estimate for the heterogeneity of the normalization pool, which determines the response to multiple stimuli. These results provide a general framework for the varying representations of multiple stimuli that were reported in different regions of category-selective cortex in neuroimaging and single-unit recording studies. This type of organization may enable a dynamic and flexible representation of complex visual scenes that can be modulated by higher-level cognitive systems according to task demands.