A fiber optic multi-channel neural recording system for freely moving rats

Abstract

Future brain-computer interfaces will benefit from technologies that enable efficient, reliable and high-speed transmission of multichannel neural data. As one approach, we present a miniature multichannel neural recording device that utilizes infrared (IR) fiber optics for dual purpose of powering active electronic circuits in the compact head-mounted module and extracting of broadband multichannel neural data. We demonstrate the microsystem's chronic performance in awake, behaving rats with intracortical neural sensors. In a prototype for small animal model, the microelectronic device architecture consisted of (i) an implantable 'front-end' carrying an ultra-low power 16-channel preamplifier and a multiplexer chip integrated directly onto a 4x4 cortical microelectrode array to access neural activity, and (ii) an ultra-light 'back-end' housing an analog-to-digital converter, a low power digital controller chip, an IR photovoltaic device and an IR microlaser, the latter to convert multiplexed multichannel neural data to a stream of IR pulses. The implanted device was able to monitor motor cortical activity in rats during free behavior for more than a month without degradation of device performance.