Analyzing Voltage Transients Under Different Stimulation Configurations and Rates in Rat Cortex

This study introduces a method for measuring the voltage transients (VTs) in different stimulation configurations as a function of stimulation rate. Utilizing a stimulator with two-electrode setup and an isolated input oscilloscope, VTs across monopolar (MP), bipolar (BP), tripolar (TP), and partial tripolar (PTP) stimulation configurations could be measured with a proper reference electrode (Ag|AgCl) without a potentiostat or custom-built stimulator. We tested this methodology with Utah electrode arrays (UEAs) with sputtered iridium oxide film (SIROF) electrodes and amorphous silicon carbide (a-SiC) encapsulation in rat cortex at 24 weeks. Our investigation revealed the impact of quasi-reference electrode (QRE) polarization, which leads to underestimating the chargeinjection capacity-max(Q_inj)-for electrode characterization.Clinical Relevance-This research offers advancement in understanding electrode behavior during neural stimulation, emphasizing the importance of protocol optimization for enhanced clinical outcomes in neural stimulation.