Objective Localization of seizure onset zone in focal epilepsy patients is a crucial step prior to surgical planning. Noninvasively achieving this goal would have a tremendous impact on clinical management of intractable seizure. Methods In a total of 39 focal epilepsy patients, we recorded and extracted 138 seizures and 1,325 interictal epileptic discharges using high-density EEG. We have investigated a novel approach for directly imaging sources of seizures and interictal spikes from high density EEG...