Dynamic control of location-specific information in tactile cutaneous reflexes from the foot during human walking

The purpose of the present study was to determine whether tactile cutaneous reflexes from the skin of the foot contain location-specific information during human walking. Muscular responses to non-nociceptive electrical stimulation of the sural, posterior tibial, and superficial peroneal nerves/each supplying a different skin area of the foot, were studied in both legs during walking on a treadmill. For all three nerves the major responses in all muscles were observed at a similar latency of —80-85 msec. In the ipsllateral leg these reflex responses and their phase-dependent modulation were highly nerve-specific. Dur ing most of the stance phase, for example, the peroneal and tibial nerves generally evoked small responses in the biceps femoris muscle. In contrast, during late swing large facilitations generally occurred for the peroneal nerve, whereas suppres sions were observed for the tibial nerve. In the contralateral le