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

Background: 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.

Methods: 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.

Results: 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.

Conclusion: 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.