A new array of brain sensors can record electrical signals directly from the surface of the human brain in record-breaking detail. The new brain sensors feature densely packed grids of either 1,024 or 2,048 embedded electrocorticography (ECoG) sensors. If approved for clinical use, these sensors would offer surgeons brain-signal information directly from the surface of the brain's cortex in 100 times higher resolution than what is available today. The technology could provide better guidance for planning surgeries to remove brain tumors and surgically treat drug-resistant epilepsy.