Drug effects under automaintenance and negative automaintenance procedures.

Three food-deprived pigeons were initially exposed to an automaintenance procedure in which brief periods of response key illumination were followed by food delivery without regard to the subject's behavior. Keypecking occurred at a high rate while the key was illuminated and was reduced in dose-dependent fashion by acute administration of LSD (0.05--0.45 mg/kg), quipazine (1.0--8.0 mg/kg), haloperidol (0.08--0.32 mg/kg), and pentobarbital (4.0--16.0 mg/kg). The animals were then exposed to a negative automaintenance procedure in which food delivery followed key illumination only if the lighted key was not contacted. Keypecking occurred at a low rate under this procedure, with no responses occurring during the majority of key illuminations and was decreased or unaffected by LSD, quipazine, and haloperidol; pentobarbital increased responding at doses of 4.0 mg/kg and 8.0 mg/kg and reduced responding at a dose of 16.0 mg/kg.