Patients with medically refractory epilepsy undergo long-term invasive monitoring for surgical resection planning. Electrodes are implanted subdurally over seizure focus to identify seizure onset zone and patients are often in the epilepsy monitoring unit at the Neuroscience hospital for approximately a week. During this period, intracranial EEG is constantly acquired for clinical investigation. The investigators plan to recruit these patients while they undergo long-term monitoring to leverage the rare access to direct brain recordings and study the role of oscillations in cognitive and affective processing. Patients who provide informed consent to participate in the study will perform computer based cognitive and emotional processing tasks.