Selective recording with a multi-contact nerve cuff electrode

A multi-contact cylindrical nerve cuff electrode was evaluated for its ability to record neural signals selectively in an in vitro preparation. Three branches of a Beagle hypoglossal nerve are stimulated sequentially while compound action potentials (CAP) are recorded from its trunk with the multi-contact cuff electrode. A selectivity index (SI) is defined and applied to the CAP recorded from the 4 sets of tripolar contacts (12 contacts in total) that are equally spaced around the cuff. The results show that the cuff can record selectively from different fascicles, but these effects are small. Connecting the contacts of the opposite set together while recording from a tripole improved the selectivity. The signal amplitudes from various contacts are consistent with the location of the fascicles relative to the contacts.