Microelectrode Array Probe for Simultaneous Detection of Glutamate and Local Field Potential during Brain Death

High extracellular potassium could induce depression-like depolarizations, elevations of extracellular glutamate and even neuronal death in brain. To investigate the contribution of high potassium in vivo , microelectrode arrays (MEAs) probe were fabricated and implanted in a rat brain for simultaneous record of striatal local field potential (LFP) and glutamate concentration. During these multi-modal recordings, the rat brain was exposed to a high potassium solution. It was observed that high potassium elevated extracellular glutamate while suppressing the LFP irreversibly. This is one of the first studies in which a dual-mode MEA probes is applied in vivo for neuronal death. It is concluded that the MEA probes are capable of examining specific spatiotemporal relationships between electrical and chemical signaling in the brain.