Multi-channel integrated neural interfaces for distributed electro-chemical sensing

Distributed monitoring of electro-chemical activity facilitates understanding various neurophysiological phenomena. Single-chip neural interfaces offer a small-size, low-power, low-noise and cost-effective alternative to commercial bench-top instruments. They present an opportunity to enhance implantable microsystems functionality with multi-site simultaneous distributed recording capability. We present two integrated neural interfaces, for chemical and electrical sensing. The first integrated neural interface performs simultaneous current-mode acquisition of 16 independent channels of redox currents ranging five orders of magnitude in dynamic range over four scales down to hundreds of picoamperes. The second neural interface acquires neural field potentials in microvolts to millivolts range on a 16times16-electrode microarray in voltage mode. Each microsystem features programmable gain amplifiers, tunable band filters, configurable sample-and-hold circuits, and is ready for external analog-to-digital conversion. Side-by-side quantitative comparison of the two neural interface technologies is given