Single-unit neural recordings using active microelectrodes

An improved fabrication process has been developed for neural probes containing on-chip signal processing circuitry, and several types of active recording amplifiers/buffers have been explored for single-unit recording in-vivo. The first three-dimensional (3D) active probe array has also been created using this process and 3D microassembly techniques. Recording experiments with buffered (active) electrode sites and adjacent unbuffered (passive) sites have clearly shown that the on-chip electronics does not degrade the noise performance of 3-4 MΩ recording channels. Test results also indicate that stabilization of the random DC drift associated with the electrochemical metal-electrolyte interface is critically important in connection with the use of high-gain on-chip preamplifiers