Cooling Reverses Pathological Bifurcations to Spontaneous Firing Caused by Mild Traumatic Injury

Experimental studies have revealed that mild trauma in the form of e.g. physical pressure or chemical stimuli can alter the properties of the main current (sodium) responsible for the voltage swings or “firings” of neurons. This leads to ongoing firings even when the cell should be quiescent. Such pathological firing interferes with the usual input integration properties of the cell, and in particular has been implicated in the genesis of pathological pain, which persists even after the injury-producing stimulus is removed. From a dynamical point of view, this mild trauma lowers the threshold for firing. This presentation explores the possibility of using temperature to offset this effect by raising the firing threshold back up (see Chaos, 28, 106328 (2018)). Our modeling study predicts that cooling the neuron by just a few degrees – as is possible e.g. for peripheral nerve cells – can counteract the pathological state. The sensitivity of the sodium current to temperature is the key determinant of this effect.