Inferotemporal face patches are histo-architectonically distinct.

An interconnected group of cortical regions distributed across the primate inferotemporal cortex forms a network critical for face perception. Understanding the microarchitecture of this face network can refine mechanistic accounts of how individual areas function and interact to support visual perception. To address this, we acquire a unique dataset in macaque monkeys combining fMRI to localize face patches in vivo and then ex vivo histology to resolve their histo-architecture across cortical depths in the same individuals. Our findings reveal that face patches differ based on cytochrome oxidase (CO) and, to a lesser extent, myelin staining, with the middle lateral (ML) face patch exhibiting pronounced CO staining. Histo-architectonic differences are less pronounced when using probabilistic definitions of face patches, underscoring the importance of precision mapping integrating in vivo and ex vivo measurements in the same individuals. This study indicates that the macaque face patch network is composed of architectonically distinct components.