Excitatory synaptic responses to paired-pulse stimulation in WT and RIM1α KO mice in the absence and presence of MG132. (A) PPF (fEPSP₂/fEPSP₁) recorded in stratum radiatum of CA1. The graph shows mean values and SEMs (error bars). Confidence values: **, P < 0.01. Compared with WT mice, RIM1α KO mice showed an increase in PPF that was reversed by MG132 treatment. (B) Representative traces. Sample sizes are as follows (slices/animals): WT, 14/4; WT + MG132, 16/4; RIM1α KO, 14/4; and RIM1α KO + MG132, 13/4.