PROJECT SUMMARY This supplement is designed to provide the applicant with experience and training in experimental neuroscience so that she may best integrate her background in computer science with her intended career in neuroscience and medicine. Social attachments form the basis of human relationships at every level of social organization. Disruptions in attachment occur across the spectrum of mental illness, and severe neuropsychiatric disorders often manifest with a dramatic collapse of social attachment and cognition. Despite this critical role of social attachment, little is known regarding the neural and genetic mechanisms underlying attachment. Mice and other genetic model organisms do not exhibit enduring social attachments, precluding genetic analysis of these behaviors. Prairie voles are small rodents that display social monogamy, or pair bonds, between mates. Pair bond formation results in dramatic changes to many other innate social behaviors. Thus, prairie voles engage in a rich repertoire of social behaviors that strikingly mirror attachment in humans. Pioneering work identified the peptide hormones vasopressin (Avp) and oxytocin (Oxt), as critical mediators of pair bonding in voles and social cognition and behaviors in humans. These findings suggest that the genetics and neural control of social attachment may be conserved, and indeed, have inspired clinical trials seeking to use these hormones to ameliorate disruptions in social cognition due to neuropsychiatric conditions. Nevertheless, how these pathways and other genes function to control specific aspects of complex social behaviors remains unknown. Until now, we have been unable to understand how OxtR and V1aR function to control patterns of neural activity in response to partners or strangers. We have generated prairie voles bearing mutations in OxtR and V1aR that completely eliminate the function of these receptors, and determined, strikingly, that OxtR is not required for pair bonding, but facilitates partner preference and sex-specifically controls prosocial behavior with strangers. Thus, a more refined understanding of the behavioral processes underlying social attachment may provide new insights into the pathways that mediate affiliation. This supplement is designed to provide training for the applicant in experimental neuroscience to facilitate her continuing education prepare her for her intended graduate and medical career. Here we propose to optimize and implement unbiased automated behavioral tracking and detection to understand the behavioral modules that facilitate pair bonding, and determine how activation of specific populations of OxtR neurons influences these behaviors. These studies will elucidate the mechanisms by which OxtR and V1aR facilitate attachment and, eventually, inform new therapeutic approaches across the spectrum of mental illness.