Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions

Abstract

Eye contact is a fundamental means of social interaction among primates. In both humans and non-human primate societies, eye contact precedes and signals aggression or prosocial behaviors. Initiating and maintaining short periods of eye contact is essential during social interactions that build trust and promote cooperation. How the brain detects and orchestrates social exchanges mediated by eye contact remains an open question in neuroscience. Theories of social neuroscience speculate that the social brain in primates contains neurons specialized to detect and respond to eye-contact. This dissertation reports the discovery and characterization of a class of neurons, located in the amygdala of monkeys, that is activated selectively during eye contact. The discovery of these cells was facilitated by (1) characterization of the response properties of neurons in the amygdala during a canonical image-viewing task and (2) development of a reliable and quantifiable method for eliciting naturalistic eye contact between monkeys in the laboratory setting. The functional role of eye contact cells remains to be determined. The data presented in this dissertation confirm the role of the amygdala in social behaviors and allows for the formulation of new hypotheses about the cellular mechanisms within the amygdala that support complex social interactions among primates.