Principles of coarse-scale functional organization in occipitotemporal cortex

Abstract

Occipitotemporal cortex is known to process visually perceived objects, yet identifying general principles underlying its coarse-scale functional organization remains challenging for two reasons. First, previous work leaves open whether proposed organizational dimensions, such as animacy or real-world size, are useful for characterizing high-level vision and whether they generalize to more diverse, naturalistic stimuli. Second, object properties are often highly intercorrelated, making it difficult to determine which dimensions, if any, dominate coarse-scale occipitotemporal cortex organization. We addressed these challenges through detailed analyses of the cortical topography underlying 15 object properties, using densely-sampled fMRI responses to thousands of natural images, and focusing on animacy and size given their established prominence. Although our results confirmed many characteristics of the purported animacy-size organization, they revealed distinctions that challenge dominant notions of this organization, highlighting the importance of generalizing to large-scale naturalistic data. Beyond animacy and size, we found that many of the 15 properties could alternatively serve as organizational dimensions of occipitotemporal cortex, yet none emerged as clearly dominant across all OTC. Together, our findings reveal a more complex animacy-size organization than previously assumed and highlight challenges of assigning individual principles to account for OTC organization.