Development of wireless neural interface system

Purpose: Advances in experimental devices have led to substantial achievements in electrophysiological studies in the last few decades. However, conventional systems tend to hinder freely moving behavioral tests, because of the use of tethering cables connecting subjects to devices. To tackle this limitation, we developed a wireless neural interface system (WNIS) that is capable of multi-channel recording and stimulation with a wireless charging battery. Methods: The WNIS was fabricated in dimensions of 34 mm × 37 mm × 6 mm and weight of 13.4 grams. It consists of two main parts: 1) a combined detection and stimulation module with wireless charging circuit and 2) a real-time remote control program. To evaluate the WNIS performance, we recorded local field potentials (LFPs) from the dorsal surface of the lumbosacral spinal cord segments and stimulated the pelvic nerves in female rats. Results: Developed system is capable of acquiring eightchannel neural signals and delivering programmed electrical stimulations with two implemented channels for neuromodulation. The acquired LFPs from in vivo experiments showed a high correlation with gradual urinary bladder distension, and the stimulation test performed in pelvic nerves induced bladder contractions and pressure increments. Conclusions: The proposed WNIS was successfully applied to wireless neural signal acquisitions and neuromodulations. This work will provide fundamental concepts for simplified experimental devices.