The intraoperative recording of potentials from the cortical surface, as part of an evaluation for epilepsy or tumor surgery, the electrodes are placed in the surface of the brain. This technique is referred to as “electrocorticography”, “intracranial EEG” or “subdural EEG”. Deep brain recording is another technique, where deep electrodes are placed into brain structures suspected as epileptic foci and may not be “seen” clearly by scalp EEG.
Locate epileptogenic lesions
Locate brain regions e.g. speech
Brain mapping e.g. sensorimotor cortex