The role of oxytocin and vasopressin in emotional and social behaviors.

This review examines evidence for the involvement of two nonapeptides, oxytocin (OT) and arginine vasopressin (AVP), in modulating the social and emotional brain in humans. We discuss research in nonclinical subjects before examining their role in various psychopathologies, mainly autism. We look at the effects of the intranasal administration of OT, and the measurement of plasma OT that appears to index brain oxytocinergic tone. Preliminary evidence for a link between intranasal OT administration and brain mirror neurons is examined. The role of AVP and its receptor AVPR1a is described, with effects that often oppose and complement those of OT in determining social and emotional behavior. The few studies involving the intranasal administration of AVP are discussed in some detail, including a first study of AVP and stress and a study of AVP and empathy. Paradigms borrowed from behavioral economics combined with a neurogenetic approach are described. These studies suggest an involvement of OT and AVP in other-regarding behaviors such as human altruism. Accumulating evidence for a role for OT, AVP, and more recently CD38 in psychopathology is described, mainly in disorders characterized by social and emotional deficits, such as autism. We end the chapter with suggestions for future research directions.