Electrical and Computer Engineering

WIMS Seminar

Silicon Neural Recording Arrays With On-Chip Electronics For In-Vivo Data Acquisition

Roy Olsson III

UM Graduate Student
Micromachined silicon recording electrodes are widely used by neurophysiologists to explore the nervous system. While passive silicon probes (without circuitry) have been used to record from up to 96 sites simultaneously, scaling to larger site counts is problematic because of the large number of interconnects necessary and the tethering forces these interconnects produce on the probe in-vivo. In order to provide large site counts with a reasonable number of lead transfers, circuits must be integrated with neural recording probes to allow front-end selection, (electronic positioning of the active sites), and time-division multiplexing (sampling of multiple neural channels onto one data lead). On-chip amplification must be included to reduce cross-talk, spurious noise, and perform anti-aliasing and impedance transformations. These integrated amplifiers must be able to filter the dc baseline potential of the electrode, which can be as high as ±300mV, while amplifying sub-60mV neural signals with a frequency content as low as 1Hz. The amplifiers must be small, low power, low noise, have low offset voltages, and have reproducible gains. A 64 site neural recording array with on-probe amplifiers and multiplexers has been developed that allows monitoring of 8 simultaneous neural channels over one data lead. The probe features capacitively-coupled neural recording amplifiers which eliminate the dc polarization of the electrode while providing an in-band gain of 40dB to the neural signals. The development of a robust on-probe analog front-end allows further data compression through in-vivo signal processing, which lays the groundwork for fully-implantable closed-loop neural prosthetic devices.

Roy H. Olsson III was born in Nevada, MO in 1976. He received B.S. Degrees in Electrical Engineering and in Computer Engineering from West Virginia University in 1999. During his undergraduate career, he interned at Oak Ridge National Laboratory, where he worked on the development of an environmental monitoring sensor with on-chip signal processing. After completing his B.S. Degrees, he interned at Lucent Technologies, where he design mixed signal electronics for cellular phone applications. In September 1999 he enrolled at The University of Michigan to pursue his Ph.D. in Electrical Engineering with a major in Circuits and Microsystems and a minor in Solid State Electronics. Roy received his Master's Degree in Electrical Engineering in December 2001.

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