IMPROVED FLEXIBLE MICROWIRE ARRAY ELECTRODE FOR INTRACORTICAL SIGNALS RECORDING

Abstract

Implanted electrodes are the first piece of hardware in an intracortical signals recording pathway. This work presents an improved flexible microwire array electrode for intracortical recordings. Only ready-made materials and general mechanical tools are used to fabricate a microelectrode. The proposed procedure is relatively simple, even for a novice worker to implement in-house. Many key steps in producing a good microwire array electrode are facilitated. These main steps include selecting materials, preparing for fabrication, and assembling the electrode. The assembly of the microwire array electrode includes connecting and positioning PCB pattern, arraying and fixing microwires, and soldering and packaging the electrode. A practiced researcher can assemble the microelectrode in about 2 h and implant it in approximately three. The mass of this assembled microelectrode is 1.96 g. 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 invasive 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 intracortical signal of cerebrum. The microwire array electrode can be fabricated and used for multi-site, multiple single-unit recording experiments. Several experimental results are presented, along with applications that demonstrate the feasibility and advantages of the proposed approach.