The representation of object concepts across the brain

Abstract

The mechanisms supporting concrete object concepts remain elusive. Here, macaque monkeys spent years learning object-concept primitives defined by color and shape. During fMRI, the monkeys held in mind one concept feature cued by the other. Using a whole-brain searchlight, we observed cross-feature decoding not in retinotopic cortex, but bilaterally in anterior inferior temporal cortex (aIT), temporal pole (TP), and frontal cortex (FC). Only TP and aIT had response patterns to concept shapes matching color-space geometry, and only PF had responses that decode behavioral errors. Two additional imaging experiments showed that color-associated versus non-color-associated shapes, and color-shape combinations congruent versus incongruent with the concepts, were distinguished only by extrastriate visual cortex, suggesting extrastriate cortex underpins color perception and perceptual feature binding. Together, the results provide a blueprint for how the brain generates stable object concepts and provides hypotheses for how conceptual representations engage perceptual representations through selective feedback during vision.