Probability of prickliness detection in a model of populations of fiber ends prickling human skin

Although it is relatively easy to judge whether the fabric is prickly, and it is very difficult in quantifying human capability of detection and judgment of fabric-evoked prickliness. As so far, no mathematical relationship is proposed to measure this detectability. On the basis of the neurophysiological property of A delta-fiber nociceptors responsible for fabricevoked prickliness and the statistical distributions of short-coarse fiber ends protruding above a fabric surface, the present study develops a model to simulate the activation probability of nociceptors, and discusses its sensitivity to the change of the typical features characterizing physical properties of coarse fiber ends and the typical physiological features of A delta-fiber nociceptors. The results show that the developed model is significantly sensitive to the changing spatial density of A delta-fiber nociceptors and their mechanothresholds, which reflects differences among person's capability in detecting and judging fabric-evoked prickliness. In terms of the effect of physical features of coarse fiber ends on the detection of prickliness, the activation probability of populations of nociceptors represents a consistent phenomenon with the subjective evaluation results in literatures. Therefore, the developed model gives a good link between somatosensory physiology and physical cues to fabric-evoked prickliness, and with psychophysical method provides an alternative prediction for the detection of fabricevoked prickliness at the probabilistic level.