Identification of the physical stimulus and the neural basis of fabric-evoked prickle

1. The neurophysiological basis for the sensation of prickle evoked by contact of some fabrics with the skin is reported. 2. Single-unit sensory nerve recordings from the rabbit saphenous nerve were used to identify the receptors responsible for fabric-evoked prickle. These recordings showed that all low-threshold mechanoreceptors were activated by fabric, but they did not show differential response to prickly and nonprickly fabrics. 3. However, the response of some nociceptors, both A delta and polymodal C, differed according to the prickliness of fabrics. Some of these receptors responded to fine von Frey hairs with buckling loads of at least 75 mgf. This suggested that the prickle stimuli on the fabric surface were protruding fiber ends that exerted loads of 75 mgf, or more, against the skin. 4. A Teflon replication technique was devised for estimating the density of these fiber ends. Estimates of the sensation magnitude of prickle from graded fabric sets by a panel of 55 subjects correlated (coefficient 0.91) with this measure of fiber end density. 5. We conclude from these results that fabric-evoked prickle is the result of low-grade activity in nociceptors and that the stimuli are protruding fiber ends exerting loads of approximately 75 mgf or more against the skin.