Electrical modeling of the cell–electrode interface for recording neural activity from high-density microelectrode arrays

Accurate electrical models are needed to support the design of modern microelectrode arrays. The point-contact model is presented thoroughly, and an area-contact model is analytically derived in order to model the electrical characteristics of the cell–electrode interface at subcellular resolution. An optimum electrode diameter for recording the electrical activity of neurons is analytically determined at 8 μm, with a cell diameter of 10 μm and a typical load capacitance of 10 pF. Finally, three-dimensional tip electrodes are characterized using the area-contact model. An improvement of the electrical coupling up to 20 dB is observed for small electrodes, in simulation.