Response to pressure and vibration of slowly adapting cutaneous mechanoreceptors in the human foot.

Unit activity from slowly adapting cutaneous mechanoreceptors of the foot and of the tibial part of the leg was recorded in man using the microneurography method. All the receptors increased their discharge frequency when pressure was applied to the zone of maximum sensitivity of their receptive field. They were also very sensitive to mechanical vibrations of small amplitude (0.2-0.5 mm) applied precisely to their zone of maximum sensitivity. Some of them are able to respond one-to-one to vibration at frequencies up to 200 Hz. The conditions of activation of the slowly adapting receptors seem to exclude a major contribution to kinaesthetic effects induced by vibrations applied to the tendon of tibialis anterior and extensor digitorum longus muscles [12].