Effect of spatial parameters on the vibrotactile threshold.

Abstract

Some spatial parameters involved in the excitation of mechanoreceptors in glabrous skin were investigated. The extent of protrusion by the contactor into the skin, the gradient and curvature of displacement produced by the contactor and contactor configuration, and the threshold for vibration as a function of frequency and contactor area were studied. Thresholds for vibration decrease in direct proportion to the extent of protrusion by the contactor. An inverse relation exists between the vibrotactile threshold and the contactor area, having a slope of 3 db. per doubling of area. Thresholds are relatively unaffected by changes in the gradient and curvature of the displacement. Differences in slope between small and large contactors are interpreted as evidence that there may be more than one receptor system in glabrous skin responsive to mechanical deformation.