Figure 4.

Temporal summation of the RIII-reflex for the 5 frequencies, for young and elders. RIII-reflex amplitude increased with frequency. It also increased from the first to the fifth stimulus of the series, and this effect was significantly greater at higher frequencies. However, RIII-reflex amplitude was not significantly different between groups across frequencies or stimulus rank. In addition, the temporal summation effect characterized by the interaction between stimulus rank and frequency was not affected by the age group (**Ps < 0.01 for pooled data from both groups; see main text for detailed statistical results).