All tactile receptors are involved in detection of vibration, although different receptors detect
different frequencies of vibration. Pacinian corpuscles can detect signal vibrations from 30 to 800
cycles per second because they respond extremely rapidly to minute and rapid deformations of the
tissues, and they also transmit their signals over type A
nerve fibers, which can transmit as many
as 1000 impulses per second.
Detection of Tickle and Itch by Mechanoreceptive Free Nerve Endings Neurophysiologic studies have demonstrated the existence of very sensitive, rapidly adapting
mechanoreceptive free nerve endings that elicit only the tickle and itch sensations. Furthermore, these
endings are found almost exclusively in superficial layers of the skin, which is also the only tissue
from which the tickle and itch sensations usually can be elicited. These sensations are transmitted by
very small type C, unmyelinated fibers similar to those that transmit the aching, slow type of pain.
