Cortical signal recording using an economical microelectrode fabricated on printed circuit board

This work presents a simple, flexible and economical microwire array electrode for extracellular cortical recordings. The proposed procedure is relatively simple, even for a novice worker to implement in-house. These main steps include design and sculpturing PCB, straightening microwires, connecting PCB pattern, arraying and soldering microwires and packaging the microelectrode. A practiced researcher can assemble the microelectrode in about two hours and implant it in approximately three. The mass of this assembled microelectrode is 1.96g. The cost of the materials in the entire array is less than US$1.5, and the array is suitable for implantation in the cortex of rats for neurophysiology studies. In this study, electrochemical impedance spectroscopy is also applied to measure the impedance and the phase between the electrode and the electrolyte, and then to obtain an equivalent circuit. The improved microwire array electrode is adopted to record the extracellular cortical signal of cerebrum. The microwire array electrode can be fabricated and used for multi-site, multiple single-unit recording experiments. Key-Words: Microelectrode, Printed circuit board, Flexible flat cable, Extracellular, Electrochemical impedance spectroscopy