Alteration of human cutaneous afferent discharges as the result of
long lasting vibration.
Ribot-Ciscar, E., J. P. Roll, M. F. Tardy-Gervet, and F. Harlay.
Laboratoire de Neurobiologie humaine, URA CNRS 372,
Universit[acute]e de Provence, Marseille, France
APStracts 3:0006A, 1996.
The unitary activities of slowly (15 SAI) and rapidly (12 FAI)
adapting skin mechanoreceptive afferent units innervating the
anterior part of the human leg and foot were recorded using the
microneurographic method. The recordings were performed both at rest
and upon applying cutaneous stimuli of various intensities, before
and after exposing the corresponding receptive fields to vibration
(0.5 mm peak to peak, 100 pulses/s, 10 minutes). The results show
that 11% of the units tested, which were previously silent, developed
a bursting pattern of post-vibratory activity, which lasted 12
minutes on average. This induced resting activity may account for the
tingling sensations usually perceived after exposure to vibration.
Furthermore, applying vibration to the cutaneous receptive fields
impaired the response properties of the corresponding cutaneous
fibers much more markedly in the case of the SA than in that of the
FA units. More specifically, less than half of the FA fibers tested
showed a post-vibratory depressed sensitivity to skin stroking
applied at various velocities, which persisted for only a few minutes
; whereas the responses of all the SA units to suprathreshold
maintained skin indentations applied with increasing amplitudes
decreased significantly for several tens of minutes. These fairly
durable changes in the transductive properties of the
mechanoreceptive afferent units probably lead to an impairment of
perceptual and sensorimotor processes and consequently may at least
partly account for the alterations in sensorimotor performance which
have been reported to occur in humans after exposure to vibration.
Received 30 January 1995; accepted in final form 28 November
1995.
APS Manuscript Number A112-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 22 January 96