A High-Density Array of 3D Microneedle-Electrodes for Evaluation of Spatial Resolution of Neuronal Activity

To understand how the brain works, it is necessary to explore the behavior of the micro-scale neural network with a high spatial resolution. Here, we propose silicon growth-based microneedle-electrode arrays with the minimum electrode's interval of 150 μm. To evaluate the spatial resolution of the neuronal signal, a 1 × 7 array of microneedle-electrodes penetrated into barrel cortex of a mouse. The spike signals recorded via the needle-electrode array were analyzed using the spike firing-rates. As the results, spatial resolution of the spike signals in the mouse's cortex is smaller than the electrode interval of 150 μm. Therefore, such high-density array of needle-electrodes are necessary to study the micro-scale neuronal network in the brain tissue.