Large-scale neural recordings with single-cell resolution in human cortex using high-density Neuropixels probes

Recent advances in multi-electrode array technology have made it possible to monitor large neuronal ensembles at cellular resolution. In humans, however, current approaches either restrict recordings to only a few neurons per penetrating electrode or combine the signals of thousands of neurons in local field potential (LFP) recordings. Here, we describe a new probe variant and set of techniques which enable simultaneous recording from over 200 well-isolated cortical single units in human participants during intraoperative neurosurgical procedures using silicon Neuropixels probes. We characterized a diversity of extracellular waveforms with eight separable single unit classes, with differing firing rates, positions along the length of the linear electrode array, spatial spread of the waveform, and modulation by LFP events such as inter-ictal discharges and burst suppression. While some additional challenges remain in creating a turn-key recording system, high-density silicon arrays provide a path for studying human-specific cognitive processes and their dysfunction at unprecedented spatiotemporal resolution. ### Competing Interest Statement K.V.S. is a consultant to Neuralink Corp. and CTRL-Labs Inc. (now a part of the Facebook Reality Labs division of Facebook) and on the Scientific Advisory Boards of Mind-X Inc., Inscopix Inc. and Heal Inc. S.D.S. is a scientific advisor to Nēsos Corp. The MGH Translational Research Center has clinical research support agreements with Neuralink, Paradromics, and Synchron, for which S.S.C. and L.R.H. provide consultative input. None of these entities listed are involved with this research or the Neuropixels device. B.D. and M.W. are employees of IMEC, a nonprofit semiconductor research and development organization that manufactures, sells, and distributes the Neuropixels probes, at cost, to the research community.