Failure to obtain functional equivalence between dopamine receptor blockade and extinction: evidence supporting a sensory-motor conditioning hypothesis.
The effects of pimozide were tested in a discrete trial paradigm. Following 8 days of continuous reinforcement training with a retractable bar, subjects were divided into 3 groups: Vehicle-Extinction; Pimozide-Extinction and Pimozide-Reinforcement. Pimozide rats received 1 mg/kg of drug 4 hours prior to test. On each of 3 test days reinforcement continued to be delivered on a continuous reinforcement schedule for the Pimozide-Reinforcement Group whereas it was no longer delivered for the other two groups. Each test day was separated by 4 drug-free days. The Pimozide-Reinforcement Group showed the least response suppression, followed by the Vehicle-Extinction and Pimozide-Extinction Groups. These results do not support the anhedonic hypothesis that dopamine containing neurons mediate reward processes and were interpreted within a sensory-motor conditioning framework.
D000818:Animals; D005108:Extinction, Psychological / Q000187:drug effects*; D008297:Male; D010868:Pimozide / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D012054:Reinforcement, Psychology / Q000187:drug effects
D011954:Receptors, Dopamine; D010868:Pimozide