Cutaneous mechanoreceptors contribute to the generation of a cortical reflex in speech

Owing to the lack of muscle spindles and tendon organs in the perioral system, cutaneous receptors may contribute to speech sensorimotor processes. We have investigated this possibility in the context of upper lip reflexes, which we have induced by unexpectedly stretching the facial skin lateral to the oral angle. Skin stretch at this location resulted in long latency reflex responses that were similar to the cortical reflexes observed previously. This location reliably elicited the reflex response, whereas the skin above the oral angle and the skin on the cheek did not. The data suggest that cutaneous mechanoreceptors are narrowly tuned to deformation of the facial skin and provide kinesthetic information for rapid sensorimotor processing in speech.