Hardware-efficient VLSI design for large scale neural signal processing

The brain is the most complex organ in the human body and, to be able to understand how it works, large-scale in-vivo sensing of neuron populations has emerged as a key research technique. Microfabricated silicon neural probes have been established as the dominant technology in this field and have achieved ever increasing densities and numbers of simultaneous recording electrodes. imec is the leader in the design and development of CMOS neural probes that achieve minimum probe-shank dimensions, high electrode density and large number of simultaneous recording channels with low-noise and low-power performances. With these probes, it is currently possible to record from many neurons spanning multiple brain regions. However, future neural probes will require even higher numbers of simultaneous recording sites to enable the study of much larger neuron populations in the brain. In addition, wireless data transmission is becoming an important requirement to allow experiments with free-moving animals without tethering cables. Thus, on-chip neural signal processing is compulsory in such system to compress the enormous raw data which take way too much power to be transmitted wirelessly. The ideal solution would be to sort the recorded neural spikes before transmission, so that only the identifiers of the recorded neurons and their spike timings need to be transmitted.