Recent progress in neural probes using silicon MEMS technology

Abstract

Extracellular recordings from the brain are the basis for the fundamental understanding of the complex interaction of electrical signals in neural information transfer. Going beyond wire electrodes and bundles of electrode wires such as tetrodes, multielectrode arrays based on silicon technologies are receiving growing attention, since they enable a pronounced increase in the number of recording sites per probe shaft. In this paper, recent innovations contributed by the authors to the development of probe arrays based on microelectromechanical system (MEMS) technologies within the EU-funded research project NeuroProbes are described. The resulting structures include passive electrode arrays based on single-shaft and four-shaft probes comprising nine planar electrodes per shaft with lengths of up to 8 mm. Further, active probe arrays with complementary metal-oxide-semiconductor (CMOS) circuitry integrated on the probe shaft, enabling the arrangement of 188 electrodes in two columns along a 4-mm-long probe shaft with an electrode pitch of only 40 μm, are described. These active probes were developed for an electronic depth control. Further, the paper reports assembly technologies for combining the probe arrays with highly flexible ribbon cables. Applications of the probes in in vivo experiments are summarized. © 2010 Institute of Electrical Engineers of Japan.