Conditioned incentive properties of a food-paired conditioned stimulus remain intact during dopamine receptor blockade.

Hungary rats were exposed to a conditioned stimulus (CS) event (either light onset or offset) before food delivery. After several weeks of contingent CS+/food pairings, animals were pretreated with either 0, 0.5, 0.75, or 1.0 mg/kg pimozide and exposed to the CS+ alone. Both vehicle- and neuroleptic-treated rats showed large elevations in locomotor activity immediately after CS+ presentation, in relation to pre-CS+ activity levels. This elevation in activity was apparently due to the conditioned motivational properties of the stimulus because animals that had previously received unpaired presentations of the CS and food failed to show similar responsiveness to the CS. Although pimozide did not affect responsiveness to the CS+, the neuroleptic did produce an overall suppression of locomotor activity during both pre- and post-CS+ periods. The results suggest that neuroleptic treatment produces a suppression of general activity but leaves the motivational properties of food-paired stimuli intact.