Intermediate
ECoG (electrocorticography)
Also known as: Electrocorticography, Intracranial EEG, iEEG, Thin-film electrode
Recording from electrodes placed directly on the brain's surface, under the skull. Much clearer than EEG, without penetrating tissue.
ECoG grids have long been used to map seizures before epilepsy surgery. Newer thin-film arrays with hundreds to thousands of electrodes, such as Precision Neuroscience’s Layer 7, give very detailed surface recordings.
Some of the best-performing speech BCIs, including UCSF’s, use high-density ECoG.
Last updated Sep 30, 2026. Educational content, not medical advice.