Fully Wireless Implantable Device Capable of Multichannel Neural Spike Recording and Stimulation for Long-Term Freely Moving Rodent Study

Abstract

Neural spike recordings provide detailed insights into the neuronal activity and serve as powerful feedback signals for closed-loop neuromodulation, which is gaining significant attention as a medical technology of the future. However, chronic preclinical evaluations of such innovations have been hindered by the tethering effects of traditional systems on naturalistic movements. Numerous untethered systems have currently promoted experiments in ambulatory animals but robust spike recording remains challenging. This study presents a fully wireless implantable device with a compact volume of 4.8 cm3, offering six-channel spike recording at 20 kHz which matches the performance of commercial benchtop systems and four-channel stimulation with <0.1% error for long-term freely moving rodent studies. Together with a 6.78-MHz magnetic resonance wireless power transfer technology, the device enables 2.4 GHz bidirectional wireless communication, ensuring stable data transmission up to 1.5 m with <0.1% data loss. The alumina ceramic-kovar hermetic sealing protects the electronics with minimal radiowave efficiency losses of 10% at 6.78 MHz and 0.1% at 2.4 GHz. Successful implantations in rats (n =5) demonstrate sustained spike recordings from the hippocampus over 60 days. Successful closed-loop seizure detection based on neural activity recording and suppression through an acute status epilepticus model highlight the potential of this device in chronic disease management applications.