An implantable microelectrode array for dopamine and electrophysiological recordings in response to L-dopa therapy for Parkinson's disease.

Dual-mode multielectrode recordings have become routine in rodent neuroscience research. However, robust and reliable application of acute, multielectrode recording methods in brain especially for in vivo research remains a challenge. In patients with Parkinson's disease (PD), the efficacy of L-dopa therapy depends on its ability to restore Dopamine (DA) neurotransmission in the striatum. In this paper, We describe a low cost thin film 16 sites implantable microelectrode array (MEA) chip fabricated by standard lithography technology for in vivo test. In urethane anesthetized rats, the MEA probes were implanted acutely for simultaneous recording of local field potentials, spikes, and L-dopa therapy evoked dopamine overflow on the same spatiotemporal scale. We present a detailed protocol for array fabrication, then show that the device can record Spikes, LFPs and dopamine variation in real time. Across any given microelectrode, spike amplitudes ranged from 80 to 300 μν peak to peak, with a mean signal-tonoise ratio of better than 5:1. Calibration results showed the MEA probe had high sensitivity and good selectivity for DA. Comparison with existing methods allow single mode recording, our neural probes would be useful for examining specific spatiotemporal relationships between electrical and chemical signaling in the brain.