Neck vibration causes short-latency electromyographic activation of lower leg muscles in postural reactions of the standing human

To study how quickly cervical proprioceptive information induced muscular responses in the lower leg to control posture in the standing human we investigated loader leg muscle electromyograph and force-plate data from 10 healthy normal subjects when perturbed b posterior neck muscle vibration, At the onset of vibration the tibialis anterior muscle was activated at latencies of 70-100 ms whilst the triceps surae muscle inhibited Lit the same latencies. At offset the opposite pattern was observed, These findings suggest that a short-latency integrate system. rather than a direct reflex. mediates the cervical influence on posture, The short latencies also imply that activation of postural muscles in response to vibration towards the neck muscles occurs faster than should be expected if it was caused only by a perceptive illusion of movement.