An Investigation into the Effect of Oxytocin in the Amygdala on Gaze Following Behavior in the Male Macaque

Abstract

Gaze-following is an essential element of social interaction, and its absence is diagnostic of autism spectrum disorder (ASD) and other neurodevelopmental disorders. Recent studies indicate that oxytocin increases attention to eyes in humans and non-human primates, and as such has possible therapeutic applications in the treatment of ASD. To test the hypothesis that oxytocin also increases gaze-following, two male rhesus macaques were given oxytocin intranasally and one was also given oxytocin injections into the nucleus basalis of Meynert (NBM) and the amygdala. The results indicate that intranasal oxytocin does increase the frequency of gaze-follows, and that this effect is likely mediated by the NBM and not the amygdala. The results also demonstrated that subjects have individual preferences (for movie monkey, gaze direction, and movement, for instance), which made them more likely to gaze-follow in response to certain movies over others. Further experiments are necessary to determine the conditions that must be met in real-life social situations that induce gaze-following in monkeys.