Effects of methsuximide and mephenytoin on the responding of pigeons under a fixed-consecutive-number schedule with and without an external discriminative stimulus.
The effects of the antiepilepsy drugs methsuximide and mephenytoin were examined in pigeons responding under a fixed-consecutive-number (FCN) schedule with and without an added external discriminative stimulus. On this schedule, food was delivered whenever subjects responded between 8 and 12 times on one response key (work key), and then responded once on a second response key (reinforcement key). Under one variant of the FCN schedule (FCN 8-SD), an external discriminative stimulus signalled completion of the response requirement on the work key; no such stimulus change occurred under the other (FCN 8) schedule. The two FCN schedules (with an without stimulus change) alternated at 5-min intervals within each session for all subjects. Methsuximide (25-200 mg/kg) and mephenytoin (40-160 mg/kg) produced generally dose-dependent decreases in percentage of reinforced response runs and rate of responding. The magnitudes of these effects were comparable under both variants of the FCN schedule.
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D004192:Discrimination, Psychological / Q000187:drug effects*; D006827:Hydantoins / Q000494:pharmacology*; D008617:Mephenytoin / Q000494:pharmacology*; D012055:Reinforcement Schedule; D013388:Succinimides / Q000494:pharmacology*
D000927:Anticonvulsants; D006827:Hydantoins; D013388:Succinimides; C100286:methsuximide; D008617:Mephenytoin