Slow touch and ultrafast pain fibres: Revisiting peripheral nerve classification.

Olausson, Håkan, Marshall, Andrew ORCID: 0000-0001-8273-7089, Nagi, Saad S and Cole, Jonathan (2024) Slow touch and ultrafast pain fibres: Revisiting peripheral nerve classification. Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, 163. S1388-2457(24)00125-1-S1388-2457(24)00125-1. ISSN 1388-2457, 1872-8952

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Abstract

One hundred years ago, Erlanger and Gasser demonstrated that conduction velocity is correlated with the diameter of a peripheral nerve axon. Later, they also demonstrated that the functional role of the axon is related to its diameter: touch is signalled by large-diameter axons, whereas pain and temperature are signalled by small-diameter axons. Certain discoveries in recent decades prompt a modification of this canonical classification. Here, we review the evidence for unmyelinated (C) fibres signalling touch at a slow conduction velocity and likely contributing to affective aspects of tactile information. We also review the evidence for large-diameter Aβ afferents signalling pain at ultrafast conduction velocity and likely contributing to the rapid nociceptive withdrawal reflex. These discoveries imply that conduction velocity is not as clear-cut an indication of the functional role of the axon as previously thought. We finally suggest that a future taxonomy of the peripheral afferent nervous system might be based on the combination of the axońs molecular expression and electrophysiological response properties.

Item Type:	Article
Uncontrolled Keywords:	Conduction velocity, Pain, Touch, Peripheral afferents
Divisions:	Faculty of Health & Life Sciences Faculty of Health & Life Sciences > Inst. Life Courses & Medical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	16 May 2024 07:24
Last Modified:	22 May 2026 18:57
DOI:	10.1016/j.clinph.2024.04.008
Open Access URL:	https://doi.org/10.1016/j.clinph.2024.04.008
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3181032
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