Classical conditioning of amphetamine-induced lateralized and nonlateralized activity in rats.

Amphetamine-induced lateralized activity (rotation) and nonlateralized activity (extra quarter turns) was classically conditioned in female rats using the test environment as the conditioned stimulus (CS) and 1.25 mg/kg d-amphetamine as the unconditioned stimulus. Conditioned lateralized activity extinguished more rapidly than nonlateralized activity. Also, d-amphetamine-induced nonlateralized activity was selectively decreased by a schedule of 50% partial reinforcement. These results indicate that the two d-amphetamine responses can be distinguished, that they are differentially affected by learning, and that a schedule of partial reinforcement can selectively attenuate one effect of a drug while leaving the other intact. In addition, haloperidol blocked conditioned lateralized activity; this suggests that the conditioned response may be, like the drug-induced response, mediated by dopamine.