Large-scale electrophysiology: Acquisition, compression, encryption, and storage of big data

• Published in: Journal of neuroscience methods Vol. 180; no. 1; pp. 185 - 192
• Main Authors: Brinkmann, Benjamin H., Bower, Mark R., Stengel, Keith A., Worrell, Gregory A., Stead, Matt
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.05.2009
• Subjects: Action Potentials - physiology; Biological Clocks - physiology; Brain - physiology; Brain - surgery; Computer Security; Cyclic redundancy codes; Data Collection - methods; Data compression; Data Compression - methods; Data encryption; EEG analysis; Electrodes, Implanted; Electroencephalography - methods; Electrophysiology - methods; Epilepsy - physiopathology; Epilepsy - surgery; Humans; Information Storage and Retrieval; Information Systems; Monitoring, Intraoperative - methods; Multiscale electrophysiology format; Neurons - physiology; Quantitative analysis; Range encoding; Signal Processing, Computer-Assisted; Software; Multiscale electrophysiology format; Data encryption; Cyclic redundancy codes; Data compression; EEG analysis; Range encoding; Quantitative analysis
• ISSN: 0165-0270; 1872-678X; 1872-678X
• DOI: 10.1016/j.jneumeth.2009.03.022

The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single-neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32 kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single-neuron action potentials, high frequency oscillations, and high amplitude ultra-slow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range-encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information.