Contribution of joint and cutaneous afferents to longer-latency reflexes in man.

Electromyographic records from wrist extensors and flexors show a short latency reflex response, M1 and a longer latency response comprising of M2 and M3 peaks. M1 corresponds to the spinal stretch reflex and hence mediated by spindle afferents. In order to determine the contribution of various afferent types to M2-M3 components and simple reaction times, reflexes were elicited before and after anaesthetic blocks of palm cutaneous and wrist joint afferents in human subjects. The results show that joint and cutaneous afferents have no significant contribution to the longer latency reflexes or simple reaction times.