Figure 7.

Changes in the magnitude of high-threshold responses during maturation. The mean integrated current for responses evoked by maximal intensity (300 or 500 μA, at low frequency) is compared across different ages in the two major categories of neurons: (A) those with convergent input, and (B) those with input only from high-threshold fibers. A, Mean integrated current was calculated by subtracting the integrated synaptic current evoked at 25 μA from that recorded at the maximal stimulation intensity. For convergent-input neurons, there was no significant difference in the mean integrated current in response to high-threshold input across age groups (17 neonatal, 12 juvenile, and 6 mature neurons; p > 0.05, one-way ANOVA, Newman–Keuls multiple comparison test). B, For the high-threshold-only neurons, there was a significant difference in mean integrated current between neonatal and juvenile ages, as well as between neonatal and mature ages (22 neonatal, 17 juvenile, and 26 mature neurons; *p < 0.05, one-way ANOVA, Newman–Keuls multiple comparison test). Error bars represent SEM.