Changes in firing probability of a ST motor unit evoked by stimulation of the GM (A and B, 2.5 × MT) and of the sural (C and D, 2.8 × perception threshold, PT) nerves are compared. Left and right plots and vertical continuous line as in Fig. 1 (bin width 1 ms). Dotted vertical lines as in Fig. 3. Latency of homonymous monosynaptic excitation from the sciatic nerve, 31 ms; distance between the stimulation sites of the sciatic and GM nerves, 35 cm and between those of GM and sural nerves, 38 cm. Number of triggers, A-D, 1099.