Optimal selection of multipolar electrode configurations for nerve burst detection

Nerve cuff electrodes are commonly used for neural stimulation and recording applications. Usually, these electrodes are composed of a limited set of metal rings, disposed around the nerve. Although widely used, this technology may be insufficient to record and stimulate in a more selective manner. Higher resolution electrodes, usually composed of a matrix of independent contact points, have been proposed in this sense. These electrodes allow for the exploration of a wide variety of bipolar or multipolar setups, for selective recording and stimulation. In this study, we propose a method to optimally select such multipolar setups and to quantitatively evaluate the performance of a multi-contact neural organic electrode (OE) in recording burst discharges from the rat's phrenic nerve. A 16-channel OE was wrapped around the phrenic nerve (studied electrode) and a suction electrode was applied to the cut-end of the same nerve (gold standard electrode). Analysis of all possible combinations of bipoles and tripoles from the OE were carried out to assess the improvement in the recording performance, measured as the signal-to-noise ratio, compared to the gold standard. The results showed that the bipolar and tripolar configuration significantly increased the overall recording performance. Such configurations are therefore essential to improve nerve burst detection.