Concurrent measurements of neurochemical and electrophysiological activity with microelectrode arrays: New perspectives for constant potential amperometry

Our current understanding of neurotransmission and neuromodulation stands to gain from concurrent electrochemical and electrophysiological measurements, which have been attempted since the introduction of in vivo electrochemical techniques. Dual in vivo recordings have evolved from parallel approaches using two distinct microelectrodes towards serial strategies encompassing “time-sharing” between two independent recording systems while using a single microelectrode. More recently, fast sampling amperometry has been demonstrated to allow concurrent measurement of rapid neurochemical and electrophysiological events using a single sensor and recording system. This is supported by the fact that the high-frequency component of an amperometric recording (>1 Hz) resembles the local field potential while the low frequency component (<1 Hz) reflects the electrochemical signal resulting from the oxidation or reduction of electroactive species present in the milieu. This opens new avenues for constant potential amperometry, widening the application of this seamless electrochemical technique.