The neurocognitive basis of gaze perception: A model for social signal processing

Observing someone else's gaze can indicate that person's direction of attention, intention, or emotion. Gaze-following is an important developmental milestone for infants, and delays in gaze-following have been shown to predict a later diagnosis of autism. Understanding the neural networks mediating gaze processing may provide insights into the neurobiology of social development as well as the specific deficits associated with autism. Brain networks involved in analyzing eye gaze were investigated in two experiments using functional Magnetic Resonance Imaging (fMRI).; In Experiment 1, brain regions involved in analyzing gaze as a directional cue were investigated using a task that required subjects to make precise discriminations concerning direction of gaze. In control tasks an arrow provided directional information instead of the eyes, or the eyes moved without providing relevant directional information. Whole-brain fMRI results (N = 10) revealed greater superior temporal sulcus (STS) activation when directional cues came from gaze than from the arrow, and greater STS activation from eye motion when it provided directional information than when it didn't. Activity in fusiform face-responsive areas and prefrontal cortex was greater in the eye motion control task compared to the gaze task, and greater when attending to gaze than when attending to the arrow, even when the arrow was superimposed on the face. These results help define the interacting networks mediating face and gaze perception and suggest that processing in the STS is instrumental for analyzing meaningful eye motion.; The same subjects participated in Experiment 2, which was designed to investigate brain regions engaged in processing eye contact. In a direct gaze detection task, subjects were required to detect direct gaze among averted gaze trials. In a blocked design, direct gaze occurred on 40% or 0% of the trials, and amygdala activity was greater in the latter condition, when the unfulfilled anticipation of direct gaze was most prominent. These data support a general role for the amygdala in monitoring for emotionally relevant events.