Evidence of phase-dependent nociceptive reflexes during locomotion in man

摘要: In 10 healthy subjects freely walking along a straightline, the effects of painful sural nerve stimulation, applied in different phases step cycle, were investigated on two antagonistic muscles ipsilateral lower limb acting knee joint: vastus lateralis (VL) and biceps femoris caput breve (BF). A clear-cut modulation amplitude (area) net reflex responses was consistently observed both motor nuclei explored. The extensor muscle, VL, exhibited long-latency (mean 122 ms) response, which maximally increased by stimuli toward end swing first half stance phase stride, whereas response appeared to be gated during transition from foot-flat forefoot-contact phase. second facilitation period brought about delivered early swing. When occurred superimposed VL locomotor activity, suppression ongoing EMG preceded discharge. flexor, BF, same stimulus elicited short-latency 57 132 response. former maximal after stimulation around toe-off latter strikingly enhanced late swing, where it background activity. Responses with intermediate features (latency 70 80 ms, duration 90 120 ms), probably resulting merging components, might evoked addition, being greatest last preceding toe-off. findings show that man pattern cutaneous locomotion is determined cycle delivered. functional role maintenance postural balance destabilizing withdrawal reactions conceivable.