Paired-pulse plasticity of CF- and PF-mediated EPSCs. A, Paired-pulse depression of CF-EPSCs of the wild-type (open circles) and PSD-93 mutant (filled circles) mice. The amplitude of the second response is expressed as a percentage of the first response (mean ± SEM) and is plotted as a function of interpulse intervals. Stimulus pairs were applied at 0.1 Hz. B, Paired-pulse facilitation of PF-mediated EPSCs. The amplitude of the second response is expressed as a percentage of the first response (mean ± SEM) and is plotted as a function of interpulse intervals. Stimulus pairs were applied at 0.2 Hz.