Until
recently, neurobiologists have used computers for simulation, data collection,
and data analysis, but not to interact directly with nerve tissue in live, behaving
animals. Although digital computers and nerve tissue both use voltage waveforms
to transmit and process information, engineers and neurobiologists have yet to
cohesively link the electronic signaling of digital computers with the electronic
signaling of nerve tissue in freely behaving animals.Recent
advances in microelectromechanical systems (MEMS), CMOS electronics, and embedded
computer systems will finally let us link computer circuitry to neural cells in
live animals and, in particular, to reidentifiable cells with specific, known
neural functions. The key components of such a brain-computer system include neural
probes, analog electronics, and a miniature microcomputer. Researchers developing
neural probes such as sub- micron MEMS probes, microclamps, microprobe arrays,
and similar structures can now penetrate and make electrical contact with nerve
cells with out causing significant or long-term damage to probes or cells.Researchers
developing analog electronics such as low-power amplifiers and analog-to-digital
converters can now integrate these devices with micro- controllers on a single
low-power CMOS die. Further, researchers developing embedded computer systems
can now incorporate all the core circuitry of a modern computer on a single silicon
chip that can run on miniscule power from a tiny watch battery. In short, engineers
have all the pieces they need to build truly autonomous implantable computer systems.