Stressor invoked exacerbation of amphetamine-elicited perseveration.

The provocation of stimulus preservation induced by amphetamine in a Y-maze was appreciably enhanced in animals that had been exposed to uncontrollable shock, whereas controllable shock did not influence performance. The enhancement of the stimulus perseveration was evident irrespective of whether the stressor was applied immediately or 72 hr prior to the perseveration test, provided that the stimulus complex in which shock was delivered was similar to that in which the perseveration test was conducted. When the two environments were distinctively different from one another the enhancement of stimulus perseveration was evident immediately after shock exposure, but not 72 hr after shock. It is suggested that stressors may have long-term effects of amphetamine-elicited perseveration, but the expression of such an effect is dependent upon the stimulus context in which the behavior is examined. Moreover, it is suggested that evaluation of amphetamine-induced behavioral changes, and possibly amphetamine-elicited and idiopathic psychosis, should consider the stress history of the organism.