Following Eye Gaze Activates a Patch in the Posterior Temporal Cortex That Is Not Part of the Human "Face Patch" System

Abstract

Humans follow another person ´s eye gaze to objects of interest to the other, thereby establishing "joint attention", a first step towards developing a theory of the other ´s mind. Previous fMRI studies agree that a "gaze following patch" (GFP) of cortex close to the posterior STS is specifically implicated in eye gaze following. The location of the GFP is in the vicinity of the posterior members of the core face processing system that consists of distinct patches in ventral visual cortex, the STS, and frontal cortex, also involved in processing information on the eyes. To test if the GFP might correspond to one of the posterior "face patches", we compared the pattern of BOLD contrasts reflecting the passive vision of static faces with the one evoked by shifts of attention guided by the eye gaze of others. The viewing of static faces revealed the face patch system. On the other hand, eye gaze following activated a cortical patch (the GFP) with its activation maximum separated by more than 24mm in the right and 19mm in the left hemisphere from the nearest face patch, the superior temporal sulcus face area (STS-FA). This segregation supports a distinct function of the GFP, different from the elementary processing of facial information.

Significance Statement Human observers follow another person´s eye gaze to objects and locations of interest to the other one, thereby establishing "joint attention", a major step toward developing a theory of the other´s mind. Previous fMRI studies agree that a patch of cortex around the posterior superior temporal sulcus is specifically implicated in eye gaze following. This "gaze following patch" is located in the same region as the posterior elements of the face patch system, also extracting information on the eyes. Using fMRI we show that the gaze following patch is distinct from the face patch system, supporting a role beyond the elementary processing of facial information accommodated by the face patch system.