Touch perception threshold in human glabrous skin in terms of displacement amplitude on stimulation with single mechanical pulses

Abstract

The threshold amplitude for tactile sensation was measured on the finger pads of normal adults using half cycle sinusoidal mechanical pulses. The threshold was about 5 μm for pulses producing rapid skin displacements. With slow pulse stimulation, a sharp rise in threshold to above 80 μm was recorded at a displacement rate of about 0.1 mm/sec. The threshold gap (difference limen) was a fraction of the threshold, on average 27%. The low threshold for rapid pulses is most probably mediated by pacinian corpuscles. The threshold rise on slow pulse stimulation indicates a transfer of the sensation to another type of units which may be the slowly adapting type I.