Scopolamine effects on juvenile conspecific recognition in rats: Possible interaction with olfactory sensitivity.

The social recognition of a juvenile conspecific by an adult male rat was evaluated as the decrease in investigation time when the same juvenile individual was reintroduced 30min after the first exposure period. The results showed that scopolamine impaired this transient individual recognition. A drop in investigation time was also observed in both tests (first and second exposure), with the same and with different juvenile individuals, in scopolamine treated animals. A second experiment showed that scopolamine disturbed the chemosensory preference for familiar odour observed in the control group. In the light of these two experiments, and according to the chemosensory mediation of social recognition in the rat, it is impossible to rule out a lack of odour discrimination in the absence of social recognition after scopolamine injection.