BCIwiki (bciwiki.com) — Four Precision Neuroscience Layer 7 micro-electrocorticography (μECoG) arrays totaling 4096 electrodes were deployed across the central sulcus during resection of a right parafalcine meningioma, densely sampling stimulus-dependent sensorimotor responses. At a 2 MΩ impedance criterion, 3739 channels were usable, a 91.3% yield, with per-array yield ranging from 86.7% to 97.0%. The results were reported in Journal of Neural Engineering on September 15, 2026.
Each array carries 1024 platinum electrodes on a flexible polyimide substrate, with 400 μm electrode pitch and roughly 1.5 cm² of active area. The patient was a 56-year-old male. Two arrays were placed horizontally on the exposed precentral gyrus; two were inserted under the intact dura overlying the postcentral gyrus using a custom flexible stylet. Somatosensory evoked potentials were recorded across 5 contralateral stimulation conditions: median nerve, ulnar nerve, index finger, middle finger and ring finger.
Per-electrode amplitude maps resolved continuous phase-reversal contours whose spatial structure varied with the stimulation condition. Reversal latencies were 19, 21, 25, 26 and 25 ms for median, ulnar, index, middle and ring stimulation respectively. Phase reversal occurred within a single array in 8 of 10 sensory-array recordings. Digit responses showed measurable spatial differentiation within substantially overlapping response fields. Automated classification of the phase-reversal responses recovered the expected motor and sensory organization, consistent with the standard-of-care intraoperative localization performed in the same case.
The authors set explicit limits on the demonstration: measured responses correlated across approximately 3-4 mm of cortex, an order of magnitude coarser than the 400 μm electrode pitch, so the contribution is dense spatial sampling rather than submillimeter physiological resolution. Dense sampling rendered the polarity transition as a continuous two-dimensional boundary across the recording field rather than a reversal between two adjacent contacts. The platform, the authors write, supports future evaluation of high-density surface μECoG for intraoperative mapping and chronic brain-computer-interface applications.