Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data.
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 32kHz 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.
Mayo Systems Electrophysiology Laboratory, 1216 Second Street SW, Rochester, MN, USA.
Benjamin H
BH
Brinkmann
Mark R
MR
Bower
Keith A
KA
Stengel
Gregory A
GA
Worrell
Matt
M
Stead
D000200:Action Potentials / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology; D001921:Brain / Q000502:physiology / Q000601:surgery; D016494:Computer Security; D003625:Data Collection / Q000379:methods*; D044962:Data Compression / Q000379:methods; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods*; D004594:Electrophysiology / Q000379:methods*; D004827:Epilepsy / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D016247:Information Storage and Retrieval; D007256:Information Systems; D016343:Monitoring, Intraoperative / Q000379:methods*; D009474:Neurons / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D012984:Software