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Published July 1, 2015 | metadata_only
Journal Article

Generalized Analog Thresholding for Spike Acquisition at Ultra-Low Sampling Rates


Efficient spike acquisition techniques are needed to bridge the divide from creating large multielectrode arrays (MEA) to achieving whole-cortex electrophysiology. In this paper, we introduce generalized analog thresholding (gAT), which achieves millisecond temporal resolution with sampling rates as low as 10 Hz. Consider the torrent of data from a single 1,000-channel MEA, which would generate more than 3 GB/min using standard 30-kHz Nyquist sampling. Recent neural signal processing methods based on compressive sensing still require Nyquist sampling as a first step and use iterative methods to reconstruct spikes. Analog thresholding (AT) remains the best existing alternative, where spike waveforms are passed through an analog comparator and sampled at 1 kHz, with instant spike reconstruction. By generalizing AT, the new method reduces sampling rates another order of magnitude, detects more than one spike per interval, and reconstructs spike width. Unlike compressive sensing, the new method reveals a simple closed-form solution to achieve instant (noniterative) spike reconstruction. The base method is already robust to hardware nonidealities, including realistic quantization error and integration noise. Because it achieves these considerable specifications using hardware-friendly components like integrators and comparators, generalized AT could translate large-scale MEAs into implantable devices for scientific investigation and medical technology.

Additional Information

© 2015 the American Physiological Society. Submitted 19 August 2014; accepted in final form 15 April 2015. Grants: B. D. He and A. Wein were supported by the Caltech Summer Undergraduate Research Fellowship. L. Srinivasan was supported by the American Heart Association Scientist Development Grant (11SDG7550015) and the UCLA Radiology Exploratory Development Grant. Disclosures: No conflicts of interest, financial or otherwise, are declared by the author(s). Author Contributions: Author contributions: B.D.H., A.W., L.R.V., J.K., and L.S. conception and design of research; B.D.H., A.W., A.G.R., and L.S. performed experiments; B.D.H., A.W., A.G.R., and L.S. analyzed data; B.D.H., A.W., L.R.V., J.K., A.G.R., and L.S. interpreted results of experiments; B.D.H., A.W., and L.S. prepared figures; B.D.H., A.W., and L.S. drafted manuscript; B.D.H., A.W., L.R.V., J.K., A.G.R., and L.S. edited and revised manuscript; B.D.H., A.W., L.R.V., J.K., A.G.R., and L.S. approved final version of manuscript.

Additional details

August 20, 2023
August 20, 2023