Conditioned place preference induced by social play behavior: parametrics, extinction, reinstatement and disruption by methylphenidate.

In this study, we investigated behavioral factors underlying conditioned place preference (CPP) induced by social interaction in adolescent rats. We found that the magnitude of socially-induced CPP depended on the social motivation of the animals and on the amount of training. After extinction, socially-induced CPP could be reinstated by a single reconditioning session. Treatment with methylphenidate, which disrupts social play behavior in adolescent rats, but not social exploratory behavior, prevented the development of socially-induced CPP. Interestingly, methylphenidate by itself induced CPP. These data demonstrate that: 1. social interaction is rewarding in adolescent rats; 2. appetitive and mnemonic factors influence the development of socially-induced CPP; 3. comparable to drug-induced CPP, socially-induced CPP can be extinguished and reinstated; 4. social play is likely to be the most rewarding aspect of social interaction in adolescent rats; 5. social context influences the subjective effects of methylphenidate.