  Electrophysiological devices are critical for mapping eloquent and diseased
brain regions and for therapeutic neuromodulation in clinical settings and are
extensively utilized for research in brain-machine interfaces. However, the
existing devices are often limited in either spatial resolution or cortical
coverage, even including those with thousands of channels used in animal
experiments. Here, we developed scalable manufacturing processes and dense
connectorization to achieve reconfigurable thin-film, multi-thousand channel
neurophysiological recording grids using platinum-nanorods (PtNRGrids). With
PtNRGrids, we have achieved a multi-thousand channel array of small (30 {\mu}m)
contacts with low impedance, providing unparalleled spatial and temporal
resolution over a large cortical area. We demonstrate that PtNRGrids can
resolve sub-millimeter functional organization of the barrel cortex in
anesthetized rats that captured the histochemically-demonstrated structure. In
the clinical setting, PtNRGrids resolved fine, complex temporal dynamics from
the cortical surface in an awake human patient performing grasping tasks.
Additionally, the PtNRGrids identified the spatial spread and dynamics of
epileptic discharges in a patient undergoing epilepsy surgery at 1 mm spatial
resolution, including activity induced by direct electrical stimulation.
Collectively, these findings demonstrate the power of the PtNRGrids to
transform clinical mapping and research with brain-machine interfaces and
highlights a path toward novel therapeutics.
