Face perception is crucial to survival among social primates. It has been suggested that a group of extrastriate cortical regions responding more strongly to faces than to nonface objects is critical for face processing in primates. It is generally assumed that these regions are not retinotopically organized, as with human face-processing areas, showing foveal bias but lacking any organization with respect to polar angle. Despite many electrophysiological studies targeting monkey face patches, the retinotopic organization of these patches remains largely unclear. We have examined the relationship between cortical face patches and the topographic organization of extrastriate cortex using biologically relevant, phase-encoded retinotopic mapping stimuli in macaques. Single-subject fMRI results indicated a gradual shift from highly retinotopic to no topographic organization from posterior to anterior face patches in inferotemporal cortex. We also constructed a probabilistic retinotopic atlas of occipital and ventral extrastriate visual cortex. By comparing this probabilistic map to the locations of face patches at the group level, we showed that a previously identified posterior lateral temporal face patch (PL) is located within the posterior inferotemporal dorsal (PITd) retinotopic area. Furthermore, we identified a novel face patch posterior PL, which is located in retinotopically organized transitional area V4 (V4t). Previously published coordinates of human PITd coincide with the group-level occipital face area (OFA), according to a probabilistic map derived from a large population, implying a potential correspondence between monkey PL/PITd and human OFA/PITd. Furthermore, the monkey middle lateral temporal face patch (ML) shows consistent foveal biases but no obvious polar-angle structure. In contrast, middle fundus temporal (MF), anterior temporal and prefrontal monkey face patches lacked topographic organization.

Although the visual representation of bodies is essential for reproduction, survival, and social communication, little is known about the mechanisms of body recognition at the single neuron level. Imaging studies showed body-category selective regions in the primate occipitotemporal cortex, but it is difficult to infer the stimulus selectivities of the neurons from the population activity measured in these fMRI studies. To overcome this, we recorded single unit activity and local field potentials (LFPs) in the middle superior temporal sulcus body patch, defined by fMRI in the same rhesus monkeys. Both the spiking activity, averaged across single neurons, and LFP gamma power in this body patch was greater for bodies (including monkey bodies, human bodies, mammals, and birds) compared with other objects, which fits the fMRI activation. Single neurons responded to a small proportion of body images. Thus, the category selectivity at the population level resulted from averaging responses of a heterogeneous population of single units. Despite such strong withincategory selectivity at the single unit level, two distinct clusters, bodies and nonbodies, were present when analyzing the responses at the population level, and a classifier that was trained using the responses to a subset of images was able to classify novel images of bodies with high accuracy. The body-patch neurons showed strong selectivity for individual body parts at different orientations. Overall, these data suggest that single units in the fMRI-defined body patch are biased to prefer bodies over nonbody objects, including faces, with a strong selectivity for individual body images.

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Although the neural processing of visual images of bodies is critical for survival, it is much less well understood than face processing. Functional imaging studies demonstrated body selective regions in primate inferior temporal cortex. To advance our understanding of how the visual brain represents bodies, we compared the representation of animate and inanimate objects in two such body patches with fMRI-guided single unit recordings in rhesus monkeys. We found that the middle Superior Temporal Sulcus body patch (MSB) distinguishes to a greater extent bodies from non-bodies than the anterior Superior Temporal Sulcus body patch (ASB). Importantly, ASB carried more viewpoint-tolerant information about body posture and body identity than MSB, while MSB showed greater orientation selectivity. Combined with previous work on faces, this suggests that an increase in view-tolerant representations, coupled with a refined individuation, along the visual hierarchy is a general property of information processing within the inferior temporal cortex.