EFFECTS OF EARLY LIFE CANNABIS EXPOSURE ON SOCIAL PLAY BEHAVIOUR AND COGNITIVE CONTROL

Cannabis use in humans often starts in adolescence. The active compounds in cannabis (∆9-tetrahydrocannabinol (THC)) act through endogenous receptor systems that can affect brain development in the developing organism. Cannabis use in adolescence has been associated with increased risk of disturbances in emotion regulation and cognitive capacities. Social play behaviour is displayed during adolescence, rewarding and important for socio-cognitive development. In this project, we assess the effect of adolescent cannabis exposure on social play behaviour, and on adult social behaviour and cognitive control. Lister-hooded rats are tested for their playfulness with similar-treated unfamiliar rats on post-natal day (P) 26. This procedure is repeated on P33, P40 and P47, the period in which play behaviour is most prominent. At least 2 hours after the play test, rats from the same homecage are exposed to cannabis smoke (low or high dose) or control smoke for 1 minute in vapor chambers. Cannabis exposure is performed on Mondays, Wednesdays and Fridays until P51. In adulthood, the social capacities of the rats are tested in a stranger encounter paradigm, i.e. after 24h of social isolation rats are placed in an arena with an equally isolated, unfamiliar and untreated stimulus rat. Behavioural control is assessed by the Behavioural Inhibition under Threat of Adversity (BITA) task and the approach/avoidance task. Preliminary results show a decrease in social play behaviour over the course of cannabis exposure with both doses, indicating a modulating effect of cannabis on this developmentally important social behaviour. Cognitive tasks are currently being performed.