Integration of head and body orientations in the macaque superior temporal sulcus is stronger for upright bodies.

Abstract

The neural processing of faces and bodies is often studied separately, despite their natural integration in perception. Unlike prior research on the neural selectivity for either head or body orientation, we investigated their interaction in macaque superior temporal sulcus (STS) using a monkey avatar with diverse head-body orientation angles. STS neurons showed selectivity for specific combinations of head-body orientations. Anterior STS (aSTS) neurons enabled more reliable decoding of head-body configuration angles compared to middle STS neurons. Decoding accuracy in aSTS was lowest for head-body angle pairs differing only in sign (e.g. head-body orientation difference of ±90° relative to the anatomical midline), and highest for aligned (0°) head-body orientations versus those with maximum angular difference. Inverted bodies showed diminished decoding of head-body orientation angle compared to upright bodies. These findings show that aSTS integrates head and body orientation cues, revealing configuration-specific neural mechanisms, and advance our understanding of social perception.