Neuromechanical Representation of Fabric-evoked Prickle: Spatial and Probability Integration

The goal of this study is to establish a link between fabric fiber features responsible for prickle and peripheral nervous responses. According to the anatomical mapping of nociceptors and their physiological property, a neuromechanical model coupling fiber-skin-nociceptor property is developed to stimulate the process of coarse fibers prickling human forearm skin. This model focuses on the content of coarse edge of fiber ends protruding from fabric surfaces, and the spatial distribution of these fibers is random. For fiber ends, their diameter and length are assumed to be normally distributed. By systematically changing the fibers ends per unit fabric surface area, or the distribution of their diameter or their length, we turn to three variables to measure the resulting neural activity of nociceptors. The results firstly confirmed the highly correction between firing rates of nociceptors and density of coarse fiber ends. Meanwhile, the firing rates of populations of nociceptors fluctuate with the density of fiber ends, as implies the probability of coarse fibers triggering nociceptors. Furthermore, the summation of firing rates over active nociceptors changes with the features of fiber ends in a power law, and closely correlates the subjective estimate. In theory, therefore, the firing rates of populations of AS nociceptors at periphery encode fiber-ends features responsible for prickle sensation by the spatial and probability integration.