IBCOM (intra-brain communication) microsystem: Wireless transmission of neural signals within the brain

We report our preliminary work to explore a new method of signal transmission for bio-implantable microsystems. Intra-brain communication or IBCOM is a wireless signal transmission method that uses the brain itself as a conductive medium to transmit the data and commands between neural implants and data processing systems outside the brain. Two miniaturized IBCOM (mu-IBCOM) CMOS chips were designed and fabricated for an in vivo test bed to transmit two prerecorded neural signals at different binary frequency shift keying (BFSK) carrier frequencies to validate the feasibility of IBCOM concept. The chips were packaged for full implantation in a rat brain except for external power delivery. The original neural signal waveforms were successfully recovered after being transmitted between two platinum electrodes separated by 15 mm with transmission power less than 650 pJ/bit for the CMOS implementation.