An FE Simulation Study on Population Response of RA-I Mechanoreceptor to Different Widths of Square Indenter

Rapid adapting type-I (RA-I) receptor is one type of mechanoreceptors in the human skin. They are believed to be responsible for the detection of stimuli that produce minute skin motion (flutter, slip, microgeometric surface features). The neurophysiological experiments in the paper [J.R. Phillips et al. J. Neurophysiol., Vol. 46, pp. 1192-1203, 1981]raise a question about why the RA-I afferent (innervated into RA-I receptor) fails to represents the stimulus with the width less than 3mm and why their response is anisotropy. It is unclear whether the skin's mechanics or the specific afferent branching of mechanoreceptors themselves are accounted for these phenomena. The present work seeks an interpretation of the neurophysiological phenomena, using a biomechanical finite-element (FE) model with a transduction sub-layer and synthetic sub-model for afferent current. The predicted afferent current matched well with the neural recordings in previous reports. This result suggests a major role of afferent branching in regard to the neurophysiological phenomena.