How social play experience shapes development of higher brain function: From synapses to behaviour

Social behavior is of great importance in human and animal life and encompasses a wide range of sophisticated social interactions. Social play behavior is believed to promote the physical, social, cognitive and emotional development of animals. Moreover, it enables animals living in social groups to practice their complex repertoire of behaviors in a simplified form. In this thesis, we test the hypothesis that social play is essential for the development of the network in the prefrontal cortex (PFC), an important brain region for behavioral flexibility in adulthood. To test this, rats are deprived of play behavior. Our research revealed a complex interaction between social play experience and the specific developmental trajectories of prefrontal subregions on inhibitory, but not excitatory, signals. In parallel experiments, adult playdeprived rats used a more simplified strategy in a PFC-dependent behavioral task. We further show that exposure to risks during play influences performance in PFC-dependent tasks and anxiety-like behaviors in adulthood and influences the development of inhibitory signals in the mPFC. In addition, our results indicated that the interactions between risky play and play deprivation were limited, suggesting that peer social play and the ability to take risks during play independently influence the development of behavior and PFC function. In summary, this thesis contributes to a better understanding of the importance of social play at the molecular and behavioral level. It becomes clear that different types of play influence different parts of brain development and behavior.