Individual differences in activity predict locomotor activity and conditioned place preference to amphetamine in both adolescent and adult rats

Individual and developmental differences in novelty seeking have been implicated in differential sensitivity to psychostimulants in rodents, but findings are mixed, The extent to which age differences in activity in a novel arena depended on test duration was examined by comparing adolescent and adult rats after 5 and after 60 min of testing (session 1). Rats were tested again after amphetamine or saline administration 24 h later (session 2) to examine whether activity in a novel arena predicts sensitivity to locomotor-activating effects of amphetamine. Data from two experiments were used to examine consistency of the findings. Only activity in 60 min sessions produced a consistent age difference (adolescent