We consider a nonlinear system of coupled ordinary differential equations (representing the excitatory, inhibitory, and T-cell potentials) based on the Gate Control Theory of Pain, initially proposed by R. Melzack and P.D. Wall in 1965, and later mathematically modeled by N.F. Britton and S.M. Skevington in 1988. Our main results focus on an optimal control problem associated with this model, where the short frequency, understood as a bounded time-dependent function, is treated as the control variable. The cost function accounts for a person's pain at a given final time and incorporates additional criteria. We demonstrate the uniqueness of the optimal control and establish the bang-bang nature of the control. In a previous section, we extend the mathematical analysis of the model developed by Britton and Skevington by presenting a series of mathematical inequalities. These inequalities strengthen the model's alignment with the principal requirements for reproducing the core structure of Pain Theory.
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Basic design of the pain gate
Qualitative representation of the potentials
Phase plain for the potentials
Monotone dependence of
Monotone dependence of
Dependence of
Dependence of
Representation of the potentials for time-depending frequencies
Phase plane for some variable frequencies
Other input types of frequencies