Electrocorticography (ECoG)

Electrocorticography (ECoG), also referred to as intracranial EEG (iEEG), stands as the gold standard procedure for identifying epileptogenic zones in patients grappling with epilepsy. Post craniotomy and partial skull removal, electrodes are meticulously implanted onto the cortical surface of the brain. These electrodes can be situated either outside the dura mater (epidural) or beneath the dura mater (subdural). This technique employs transparent grids, each electrode contact numbered for reference.

ECoG signals encompass synchronized postsynaptic potentials (local field potentials) originating from pyramidal cells. Temporal resolution for ECoG hovers around 5 milliseconds, while spatial resolution approximates 1 centimeter on the cortical surface and 0.5 – 3 millimeters for measuring local field potentials using depth electrodes.

ECoG facilitates the pinpointing of cortical regions involved in language processing by enabling stimulation, recording, and analysis of event-related spectrum responses during auditory, linguistic, and memory tasks.

Forseth, K. J., Hickok, G., Rollo, P. S., & Tandon, N. (2020). Language prediction mechanisms in human auditory cortex. Nature. Communications, 11(5240), 1–14. https://doi.org/10.1038/s41467-020-19010-6