Neural stimulation electrode impedance

Micro electrode neural probes facilitate the functional stimulation or recording of neurons in the central nervous system and peripheral nervous system. Minimizing the electrode impedance is an important requirement for obtaining high quality signals (high signal-to-noise ratio). It has been shown [59,60] that... 

Recently, we reported work on the evaluation of PEDOT for neural stimulation applications [33]. PEDOT was electrochemically deposited on thin-film Pt electrodes of stimulation electrode arrays to evaluate its properties for chronic stimulation. The coated electrodes demonstrated much lower impedance than thin-film Pt due to the high surface area and high ion conductivity across the film. The PEDOT film also presents intrinsic redox activity, which contributes to the low impedance as well as a much higher charge storage capacity. The charge injection limit of PEDOT electrodes was found to be 2.3 mC/cm, comparable to IrOx, and much higher than... 

A neural stimulation system typically uses constant current to deliver charges required to excite cells or neurons however, this often causes voltage excursion to exceed 1 V on the stimulation electrode. In comparison, impedance spectroscopy traditionally operates in the 5-50 mV range, typically 10 mV, without dc bias for simplicity in data interpretation [34, 109]. However, the small potential without dc bias does not accurately reflect the performance at high potentials that are involved in oxidation or reduction reactions for conducting polymers. In fact, electrode... 

---