Fig. 3

The mean of the population spike (PS) amplitude in dentate gyrus granule cells following a 400-Hz high-frequency stimulus applied to the perforant pathway. Tukey’s post hoc tests indicated that the PS amplitude in the 5 mg/kg methamphetamine (METH) group was significantly higher than those in all other groups at all assessment times. Additionally, PS amplitudes were lower in the 10 mg/kg METH group at all time points than in the 5 mg/kg METH group (P < 0.001). One-way analysis of variance revealed significant effects at the 5 min and 30 min time points for comparisons between 10 mg/kg METH, 1 mg/kg METH, and control groups; the PS amplitudes in granular cells of dentate gyrus decreased (^***P < 0.001 5 mg/kg METH vs control and 1 mg/kg METH group), ^!!!P < 0.01 (10 mg/kg vs 5 mg/kg METH, ^$P and ^$$P < 0.05 and 0.01, respectively, 10 mg/kg vs 1 mg/kg METH)