Different indentation velocities activate different populations of mechanoreceptors in humans

Abstract

We have examined whether different skin machanoreceptors are activated by different indentation velocities of a tactile probe. Indentations of 300 μm at velocities of 100 and 400 μm/ms were applied at the dorsolateral side of the foot and at the tip of digit III. Compound sensory action potentials (CSAPs) were recorded from the sural and median nerves, respectively. The amplitudes of the tactile CSAPs were <1–2 μV, and less than 15% of the CSAPs evoked by electrical stimulation. The areas of the polyphasic tactile CSAPs were 35–38% smaller at 100 μm/ms than at 400 μm/ms. The maximal sensory nerve conduction velocities (SNCVs) were higher in the median than in the sural nerves. In both nerves, the SNCVs were similar at electrical and 400‐μm/ms tactile stimulation but 11–17% lower at 100‐μm/ms stimulation. Cocaine hydrochloride was applied iontophoretically at the dorsolateral side of the foot, causing a decrease of 50% of the CSAP evoked by 100 μm/ms but only 14% at 400 μm/ms. These studies suggested that indentation at 400 μm/ms activated mainly deeply placed (Pacini corpuscles) and to some extent superficial mechanoreceptors, whereas the 100‐μm/ms indentation activated primarily superficially situated receptors (Meissner corpuscles, and some slowly adapting units). © 1998 John Wiley & Sons, Inc. Muscle Nerve 21:858–868, 1998.

The structure of the cushions in the feet of African elephants (Loxodonta africana)

“…These sensory receptor organs are responsive to pressure and especially to vibration (Cutts & Krause, 1983; Leem et al. 1993; Simonetti et al. 1998).…”

Compound sensory action potential in normal and pathological human nerves

“…The most distal end of the sensory nerve fiber may be particularly liable to adverse changes in different types of neuropathy; however, study of the receptor associated part of the nerve fiber requires different stimulation methods than the electrical pulses used to activate the whole sensory nerve trunk 18, 19. The advantage of application of tactile stimulation may be the more precise localization of pathology, and that different receptors may be approached using relatively simple changes in the indentation rate 4, 115…”

“…2). Stimulation of tactile receptors and recording of the SNAP have been used in both normal and diseased nerve to identify different types of receptors and to localize primary pathological changes 4, 18, 19, 27, 49, 71, 74, 115…”

Sensation, mechanoreceptor, and nerve fiber function after nerve regeneration

“…Previous studies have raised the possibility that that sensation could recover because of cortical plasticity, despite poor peripheral nerve regeneration. 15 This method allows recording of a SNAP and analysis of the receptorassociated responses 16 to provide insight into recovery of mechanoreceptor function after reinnervation. Clinical recovery was measured by quantitative sensory hand function tests.…”