Wireless multi-channel sensor for neurodynamic studies

This paper presents the design of a bio-compatible, implantable neural recording device for Aplysia californica, a common sea slug. Low-voltage extracellular neural signals (<100 μV) are recorded using a high-performance, low-power, low-noise preamplifier that is integrated with programmable data acquisition and control, and FSK telemetry that provides 5-kbps wireless neural data through 18 cm of saltwater. The telemetry utilizes an 8-cm electric dipole antenna matched to 50 Ω by exposing the ends of the antenna to the saltwater. A 3-V lithium ion battery (160 mAh) allows 16 hours of recording. Neural data obtained using extracellular nerve electrodes and a wired interface to this device have 2.5-µVrms noise, comparable to commercial neural recording equipment.