No abstract

Humans follow another person’s eye gaze to objects of interest to the other, thereby establishing joint attention, a first step toward developing a theory of the other’s mind. Previous functional MRI studies agree that a “gaze-following patch” (GFP) of cortex close to the posterior superior temporal sulcus (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 whether the GFP might correspond to one of the posterior face patches, we compared the pattern of blood oxygenation level–dependent (BOLD) imaging 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 24 mm in the right and 19 mm in the left hemisphere from the nearest face patch, the STS face area (FA). This segregation supports a distinct function of the GFP, different from the elementary processing of facial information.

Faces attract the observer’s attention toward objects and locations of interest for the other, thereby allowing the two agents to establish joint attention. Previous work has delineated a network of cortical “patches” in the macaque cortex, processing faces, eventually also extracting information on the other’s gaze direction. Yet, the neural mechanism that links information on gaze direction, guiding the observer’s attention to the relevant object, has remained elusive. Here we present electrophysiological evidence for the existence of a distinct “gaze-following patch” (GFP) with neurons that establish this linkage in a highly flexible manner. The other’s gaze and the object, singled out by the gaze, are linked only if this linkage is pertinent within the prevailing social context. The properties of these neurons establish the GFP as a key switch in controlling social interactions based on the other’s gaze.