Individual differences in the effect of novel environmental stimuli prior to amphetamine self-administration in rats (Rattus norvegicus)

These experiments determined whether individual differences in response to novelty subsequently predict the ability of novel stimuli, presented prior to the session, to decrease amphetamine self-administration. Using an inescapable locomotor test, the authors found that high-responder rats (Rattus norvegicus) showed a greater novelty-induced decrease in the acquisition of self-administration compared with low-responder rats. This effect was dose dependent and generalized to sucrose-reinforced responding. Using a free-choice place preference test, the authors found that high-novelty-seeking rats also showed a greater novelty-induced decrease in the acquisition of self-administration compared with low-novelty-seeking rats. Regardless of individual differences, novelty had little effect on amphetamine self-administration during the maintenance phase. These results suggest that exposure to novel environmental stimuli may reduce acquisition of drug-taking behavior, especially among high-novelty-seeking individuals.