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The Utah array powers cutting‐edge projects for restoration of neurological function, such as BrainGate, but the underlying electrode technology has itself advanced little in the last three decades. Here, advanced dual‐side lithographic microfabrication processes is exploited to demonstrate a 1024‐channel penetrating silicon microneedle array (SiMNA) that is scalable in its recording capabilities and cortical coverage and is suitable for clinical translation. The SiMNA is the first penetrating microneedle array with a flexible backing that affords compliancy to brain movements. In addition, the SiMNA is optically transparent permitting simultaneous optical and electrophysiological interrogation of neuronal activity. The SiMNA is used to demonstrate reliable recordings of spontaneous and evoked field potentials and of single unit activity in chronically implanted mice for up to 196 days in response to optogenetic and to whisker air‐puff stimuli. Significantly, the 1024‐channel SiMNA establishes detailed spatiotemporal mapping of broadband brain activity in rats. This novel scalable and biocompatible SiMNA with its multimodal capability and sensitivity to broadband brain activity will accelerate the progress in fundamental neurophysiological investigations and establishes a new milestone for penetrating and large area coverage microelectrode arrays for brain–machine interfaces. [ABSTRACT FROM AUTHOR]

Abstract: Recording neural activity during neurosurgical interventions is an invaluable tool for both improving patient outcomes and advancing our understanding of neural mechanisms and organization. However, increasing clinical electrodes' signal‐to‐noise and spatial specificity requires overcoming substantial physical barriers due to the compromised metal electrochemical interface properties. The electrochemical properties of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) based interfaces surpass those of current clinical electrocorticography electrodes. Here, robust fabrication process of PEDOT:PSS microelectrode arrays is demonstrated for safe and high fidelity intraoperative monitoring of human brain. PEDOT:PSS microelectrodes measure significant differential neural modulation under various clinically relevant conditions. This study reports the first evoked (stimulus‐locked) cognitive activity with changes in amplitude across pial surface distances as small as 400 µm, potentially enabling basic neurophysiology studies at the scale of neural micro‐circuitry. [ABSTRACT FROM AUTHOR]

We report a new hybrid integration scheme that offers for the first time a nanowire-on-lead approach, which enables independent electrical addressability, is scalable, and has superior spatial resolution in vertical nanowire arrays. The fabrication of these nanowire arrays is demonstrated to be scalable down to submicrometer site-to-site spacing and can be combined with standard integrated circuit fabrication technologies. We utilize these arrays to perform electrophysiological recordings from mouse and rat primary neurons and human induced pluripotent stem cell (hiPSC)-derived neurons, which revealed high signal-to-noise ratios and sensitivity to subthreshold postsynaptic potentials (PSPs). We measured electrical activity from rodent neurons from 8 days in vitro (DIV) to 14 DIV and from hiPSC-derived neurons at 6 weeks in vitro post culture with signal amplitudes up to 99 mV. Overall, our platform paves the way for longitudinal electrophysiological experiments on synaptic activity in human iPSC based disease models of neuronal networks, critical for understanding the mechanisms of neurological diseases and for developing drugs to treat them. [ABSTRACT FROM AUTHOR]