The structure and function of a slowly adapting touch corpuscle in hairy skin.
1. Slowly adapting cutaneous mechanoreceptors, in the cat and primates, have been studied by histological and neurophysiological methods.2. Each touch corpuscle is a dome-shaped elevation of the epidermis, whose deepest layer contains up to fifty specialized tactile cells.3. Nerve plates, enclosed by the tactile cell (Merkel cells), are connected to a single myelinated axon in the dense collagenous core of the corpuscle.4. The corpuscle generated > 1000 impulses/sec when excited by vertical surface pressure. The response was highly localized and showed a low mechanical threshold, the frequency being dependent upon the velocity and amplitude of the displacement. There was a period of rapid adaptation before a sustained response which might continue for > 30 min.5. A quantitative analysis of the responses to excitation by displacements of differing amplitude, velocity and duration is included.6. The discharge of touch corpuscle units evoked by a mechanical stimulus was temperature-sensitive, and was enhanced by a fall in skin temperature.
D000222:Adaptation, Physiological; D000818:Animals; D001369:Axons / Q000502:physiology; D002415:Cats; D004594:Electrophysiology; D006197:Hair / Q000166:cytology; D000882:Haplorhini; D011312:Pressure; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000502:physiology*; D012879:Skin Physiological Phenomena; D013696:Temperature; D013997:Time Factors; D014110:Touch