Effects of haloperidol on the biophysical characteristics of operant responding: implications for motor and reinforcement processes.
Food-deprived rats were reinforced with sweetened condensed milk for pressing a force-sensing operandum on a continuous reinforcement basis. Force was continuously recorded (every 0.00195 sec) during each response, and measures derived from the resulting force-time waveforms served as the basis for evaluating neuroleptic challenge in the form of haloperidol (0.04, 0.08, 0.16 mg/kg). Significant dose-related drug effects included a decrease in response rate, an increase in mean emitted peak force, and an increase in overall response duration. Additional quantitative analyses revealed that the drug-induced increase in response duration resulted primarily from a slowing in the animal's paw removal from the force-sensing operandum. The findings are analogous to deficits in Parkinson's disease and suggest a behavioral mechanism that might account for much of the rate attenuating effects of neuroleptics. Implications for motor and reward interpretations of the actions of dopamine antagonists are also discussed.
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012054:Reinforcement, Psychology; D013997:Time Factors
D006220:Haloperidol