Large-scale neural recordings with single neuron resolution using Neuropixels probes in human cortex

Recent advances in multi-electrode array technology have made it possible to monitor large neuronal ensembles at cellular resolution in animal models. In humans, however, current approaches restrict recordings to 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, locations along the length of the electrode array, waveform spatial spread, and modulation by LFP events such as inter-ictal discharges and burst suppression. While some challenges remain in creating a turn-key recording system, high-density silicon arrays provide a path for studying..., Patients & clinical/research electrode placement
All patients voluntarily participated after informed consent according to guidelines as monitored by the Massachusetts General Brigham (previously Partners) Institutional Review Board (IRB) Massachusetts General Hospital (MGH). Participants were informed that participation in the experiment would not alter their clinical treatment in any way, and that they could withdraw at any time without jeopardizing their clinical care. Participants were not compensated monetarily for participating. Recordings in the operating room were acquired with 9 participants (mean= 59 years old, ranging from 34 to 75; 7 female) who were already scheduled for a craniotomy for concurrent clinical intraoperative neurophysiological monitoring or testing for mapping motor, language, and sensory regions and removal of tissue as a result of tumor or epilepsy or undergo intra-operative neurophysiology as part of their planned deep brain stimulator (DBS) placement. ..., We report and load only the three successful recordings from the cortex of temporal and frontal lobes in patients undergoing brain tissue resection to treat epilepsy (Pt. 03, N=1, under general anesthesia, lateral temporal lobe) or during the implantation of DBS leads to treat movement disorders (Pt. 01 and Pt. 02; N=2, one awake (Pt. 02) and one under general anesthesia (Pt. 01), dorsolateral prefrontal cortex) using Neuropixels probes. In our paper, we also reported unsuccessful recordings – and lessons learned -- from six cases performed while developing these approaches. Unsuccessful recordings were either due to electrode fracture (N=2, with the devices and pieces fully recovered) or excessive noise during the recordings (N=4). Two different types of arrays were tested. In the first two attempts, we used the original Neuropixels 1.0 probe but found it to be too fragile.  Instead, we developed a variant  featuring a thicker shank (Neuropixels 1.0-ST: thickness: 100µm, width: 70 µm, ...