Grant: Discovery Grants Program - Individual

The most common form of play in non-human mammals is `rough-and-tumble' play or `play fighting', which is a non-injurious form of competitive interaction in which partners compete for some advantage, such as being able to bite their partner gently. Behavioural mechanisms exist that reduce the risk of play fighting escalating into serious fighting by incorporating some level of cooperation into the competition. This juxtaposition of competition and cooperation makes play fighting a useful window for studying the neurobiology of social behaviour. When animals such as rats are deprived of the opportunity to engage in peer-peer play as juveniles, they exhibit impoverished social skills as adults, such that their ability to mate successfully or negotiate dominance relationships is diminished. My work has shown that damage to the prefrontal cortex of socially reared rats produces social deficits like those present in rats deprived of play. Further, findings from my laboratory suggest that the anatomy of the neurons of the prefrontal cortex is modified when varying the experiences of play that animals have had as juveniles. Therefore, I theorize that play fighting experience as juveniles is important for the development of those areas of the brain that are critical for social competency. In the proposed research, I will use laboratory rats to investigate aspects of play experience that are critical for brain development and characterize the mechanisms by which a more competent social brain executes effective social behaviour. For example, improved performance may arise from the enhanced ability to sequence together complex movements or by attenuating the effects of fear arising from novel and unpredictable social contexts. Improved social competence may also derive from an enhanced ability to interpret and/or deliver social signals, such as the myriad 50-kHz calls that rats emit during social interactions, including play. I will conduct comparative analyses of play in primates to determine whether the organization of play fighting differs among species depending on the complexity of their social behaviour. Based on my preliminary findings, I hypothesize that, species with more complex social systems, requiring them to negotiate more varied social relationships, have patterns of play as juveniles that are modified in ways that provide training for the social skills they will need as adults. Together, these studies will characterize how social competence in adulthood develops and how the experience of play as juveniles contributes to it. Given the critical role of play in developing social skills and negotiating relationships, the research has implications beyond basic science. The proposed work will provide valuable insights on housing captive social animals and in developing strategies to facilitate experiences helpful to children.