Skin Pain Sensation Under Mechanical Stimulus: WindUp and RampOff

Abstract

Researchers have been studying the pain sensation extensively in the past few decades. Quantitative simulation and theoretical modeling of pain sensation based on experimental results are necessary for pain research. Many theories have been proposed to explain the mechanism of pain from molecular, cellular, and neuron network perspectives. But some phenomena in pain sensation are not fully understood, including windup and rampoff. This paper focused on the theoretical model of windup and rampoff phenomena in the pain sensation. With the addition of the transduction model, the generation mechanism of windup and rampoff is better explained. The simulations were carried out to analyze the skin pain sensation under the mechanical stimulus, consisting of four different parts: the mechanical model of skin, transduction, transmission, modulation, and perception. The stress distribution on the skin was obtained based on the elastic theory. And the modified Hodgkin and Huxley model and the mathematical model of gate control theory were utilized to analyze the process of transduction, modulation, and perception, respectively. The numerical experiments demonstrated the windup occurs with a frequent stimulus of 1 Hz and 2 Hz, and rampoff appears with the withdrawal of constant mechanical stimulus, which could contribute to the understanding of the pain sensation mechanism.