Vibrotactile thresholds for hairy skin.

Abstract

Absolute vibrotactile thresholds were determined as a function of stimulus frequency and contractor area on the hairy skin of the volar forearm. Thresholds for vibration decrease in direct proportion to the contractor area with a slope of -3 db. per doubling of area. When plotted as a function of frequency these data yield a U-shaped curve with a slope of -12 db. in lower frequencies and +9 db. in frequencies above 220 cps. Both these findings confirm previous data obtained on glabrous skin. Some differences between hairy and glabrous skin were found and discussed. Evidence is presented in support of a hypothesis advanced in earlier papers which suggests that there may be 2 types of mechanoreceptors in cutaneous tissue.