Or intracranial EEG (iEEG), is the practice of using electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. ECoG may be performed either in the operating room during surgery (intraoperative ECoG) or outside of surgery (extraoperative ECoG). Because a craniotomy (a surgical incision into the skull) is required to implant the electrode grid, ECoG is an invasive procedure.
see Cortical stimulation.
The detectability of high frequency oscillations (HFO, >200Hz) in the intraoperative ECoG is restricted by their low signal-to-noise ratio (SNR).
Low-noise amplification improves the detection of the evoked high frequency oscillations (HFO, >200Hz) in recordings with subdural electrodes with low impedance 1).