Effects of mephenytoin and methsuximide on the reaction time of pigeons.

Although antiepilepsy drugs are used clinically, their behavioral effects are poorly understood. The present study examined the effects of mephenytoin and methsuximide, two antiepilepsy medications, on the reaction times of pigeons. Pigeons were trained to depress and hold a foot treadle until a stimulus change occurred. Releases within 2 sec of the stimulus change were reinforced with access to mixed grain; premature releases or releases occurring after the 2-sec limited hold were not reinforced. Mephenytoin (40, 60, 80, 120, and 160 mg/kg) and methsuximide (25, 50, 75, and 100 mg/kg) produced generally dose-dependent increases in median reaction times and decreases in percent responses that were reinforced. The present procedure has not previously been used with pigeons and is a promising technique for the study of reaction time with this species.