Automated system for measuring tip impedance and among-electrode shunting in high-density microelectrode arrays

Microelectrode arrays are being routinely used today as a means to better understand and interface with the nervous system, in order to develop prostheses that can restore function in systems that do not function properly. The development and effective use of robust high-­?channel-­?count microelectrode arrays for neuronal recording and stimulation depends on effective monitoring of electrode impedances and how these change over time. For multielectrode arrays, conventional electrode impedance measurements may be confounded by possible shunting of signals among electrodes. Additionally, most present methods to monitor impedances in high-­?electrode-­?count arrays are laborintensive, requiring manual testing of one individual electrode at a time. The research effort described herein included the development of a system capable of automatically measuring the impedances of each microelectrode on a 100-­?microelectrode array with a 1-­?kHz, 10-­?mV sine wave.