Developmental increase in short-term synaptic plasticity. (A) Representative traces of fEPSP slopes at half maximum at two developmental stages during paired stimulation at 50-ms interpulse interval, average of five traces [A1, immature (P6); A2, adult (P114)]. (B) PPR at different developmental ages (ANOVA with Fisher’s post hoc comparison of significance of PPR vs. age between groups, F4,25 = 8.71, P = 0.0002; P1, n = 4; P3, n = 6; P6, n = 11; P9, n = 6; P15, n = 4; adult, n = 3 animals). **P < 0.01 and ***P < 0.001.