Ashley E. Marquardt¹, Aidan L. Pham¹, Christi V. Dionisis¹, Gabrielle E. Voithofer¹, Lucy A. Sirrs¹, Jonathan W. Van Ryzin² and Margaret M. McCarthy¹

Physical play among adolescents is a unique social behavior notable for its transient expression and independence from reproductive drive and aggression. Both males and females engage in social play but on average play by males is more intense in frequency and duration, a feature common to every species that exhibits adolescent play. Work in the laboratory rat establishes that the neural network of play is overlapping with circuits controlling adult reproductive and aggressive behaviors as well as the reward circuitry. Interestingly, the sex bias in play is not a distributed property of these circuits but instead localized to the medial amygdala (MeA) and programmed by androgens in developing males, although play is expressed at a time of life free of gonadal steroids. This led us to ask the following questions; 1) what are the cellular mechanism by which androgens developmentally masculinize play behavior, 2) is there a sex difference in the transcriptomics of play, 3) does engaging in play impart value to animals and, if so, does it differ by sex, and 4) are the lower play rates in females a default due to lack of androgen or the result of active feminization? This talk will provide answers to each and highlight new avenues for exploration of this often over looked, under appreciated yet vital social behavior.

1- Department of Pharmacology and Physiology, Program in Neuroscience, UM-MIND, University of Maryland School of Medicine.

2- Department of Psychology and Neuroscience, University of North Carolina