Spatial characteristics of evoked potentials elicited by a MEMS microelectrode array for suprachoroidal-transretinal stimulation in a rabbit

摘要: Suprachoroidal-transretinal stimulation (STS) can potentially restore vision. This study investigated the spatial characteristics of cortical electrical evoked potentials (EEPs) elicited by STS. A 4 × 4 thin-film platinum microelectrode stimulating array (200 μm electrode diameter and 400 μm center-to-center distance) was fabricated a micro-electro-mechanical systems (MEMS) techniques implanted into suprachoroidal space albino rabbits. The current threshold to elicit reliable EEPs single 41.6 ± 12.6 μA, corresponding 66.2 ± 20.1 μC · cm−2 charge density per phase, which lower than reported safety limits. Spatially differentiated responses could be STS through different rows or columns stimulation; furthermore, shifts in location maximum activities were consistent with visuotopic maps; increasing number simultaneously electrodes increased response amplitudes expanded spread as well. In addition, long-term implantation MEMS are necessary evaluate systematically biocompatibility this approach. indicates that approach MEMS-based is feasible alternative for visual restoration, relatively high discrimination may achieved.