surgical procedure electrode implantation true https://www.ncbi.nlm.nih.gov/pubmed/24405074 Implanted EEG electrodes are often necessary to pinpoint the origin of seizure activity. They are particularly helpful for more precisely localizing seizure activity that has been identified with scalp EEG recordings. For example, the scalp recordings may determine that seizures arise from the right hemisphere. Implanted EEG electrodes can then reveal whether the epileptogenic activity arises specifically from the frontal lobe, rather than the temporal, parietal, or occipital lobes. These invasive electrodes allow EEG recording directly from the surface of the brain or from deeper cortical structures.