Neural Signal Recording: Opportunities and Challenges

Abstract:
Acquisition of bio signals using a fully integrated design is desirable in
advanced medical applications. Recording of nerve signals to control
functional electrical stimulation prostheses, detection and localization
of brain activity and acquisition of the electrocardiogram or surface
electromyogram as part of a wearable or implantable monitoring system are
some of such applications. One of the crucial building blocks in a
wearable device is the sensor interface for picking up extremely small
input signals and providing a preconditioned signal to the subsequent
processing system. Amplitudes of the signals to be recorded are typically
of the order of tens of microvolts to tens of millivolts and the
frequencies span from DC to a few kHz.

We present the design, fabrication and testing of very low noise analogue
signal-capture sections of a ten-channel implantable amplifier system to
be mounted directly on the multielectrode nerve cuff. We also describe
preliminary in-vitro experiments in frogs, which provide the first
practical validation of the velocity selective recording process. The
system has an overall gain of 10,000 and a total input-referred RMS noise
per channel of less than 300 nV in a bandwidth of 1 Hz–5 kHz.

About the Speaker:
Prof. Dipankar Pal did his B.Tech from IIT Delhi and Ph.D. from Jadavpur
University, Calcutta, in the area of analogue and mixed mode circuits.
He did his post doctoral research in the University College London and
University of Bath, UK where he worked on wet-electronics, analogue VLSI
and ASIC with emphasis on current-mode circuits, biomedical and low power,
low frequency applications. Before moving to BITS, he had served as the
Director of the North Eastern Regional Institute of Science & Technology
(NERIST). Prof. Pal has guided a number of PhD's and has over 50
publications in peer reviewed journals and conferences.