A Setup for Conduction Velocities and Temperature Gradients Measurements during Infrared Neurostimulation

Infrared Neural Stimulation (INS) is a novel neuromodulation technique involving a rapid temperature increase of the neuron membrane, resulting in action potential triggering. This paper describes an experimental setup developed to measure the spatiotemporal temperature gradients at the surface of an ex vivo sciatic nerve. The setup is also designed to measure the conduction velocity of the nervous fibers excited by INS, with the aim of determining the type of fibers activated during optical stimulation. Two animal experiments successfully validated the setup and provided encouraging results on (1) the impact of heat accumulation on INS and (2) the difference in nerve fibers excited by optical and electrical nerve stimulation.