Assessment on selectivity of multi-contact cuff electrode for recording peripheral nerve signals using Fitzhugh-Nagumo model of nerve excitation.

Abstract

Nerve cuff electrodes provide a safe technique for recording nerve signals. Defining a more realized modeling to investigate the selectivity of a cuff electrode in recording from peripheral nervous system is an interesting field of research. A four-contact cuff electrode was modeled to evaluate selective recording from a peripheral nerve. Fitzhugh-Nagumo equations were used to model the electromagnetic fields generated by active nerves and electrodes and the ``selectivity index'' used to quantify the selective property of the cuff electrode. The action potentials amplitude and impulse velocity generated by Fitzhugh-Nagumo model are similar to real-life nerve measurements according to the literature. The electrical field distribution caused by the impulse propagation along a specific nerve was the maximum near the corresponding contact. Also, the selectivity was increased with increasing the distance between the active sources and the number of contacts. The results of this research showed that Fitzhugh-Nagumo equations could model the nerve excitation accurately and could be used in computer simulation for studying nervous systems. Also, using these equations indicated that multi-contact cuff electrodes could be used in recording peripheral nerve signals in order to discriminate active fascicles in a nerve bundle.