Figure 3.

(A) The effect of phenytoin pretreatment (25–100 mg/kg, i.p.) on the deficit produced by d-amphetamine (0.5 mg/kg, i.p.) on performance of the initial and reversal phase of the reversal learning task. Data are shown as the mean total number of lever presses, correct responses are shown as clear bars and incorrect responses are shown as shaded bars (n = 8 per group). (B) The effect of phenytoin pretreatment (25–100 mg/kg, i.p.) on the deficit produced by d-amphetamine (0.5 mg/kg, i.p.) on performance of the reversal phase in a reversal learning task. Data are shown as mean ± S.E.M. percentage correct responding (n = 8 per group). Significant reduction in performance of the reversal phase compared with the initial phase; *P < 0.05, **P < 0.01, ***P < 0.001. Significant reduction in performance of the initial and reversal phase compared with the respective vehicle group; ^††P < 0.01, ANOVA followed by Dunnett's t-test.