Experiment 3: Epilepsy patients  Inclusion criteria:  Adult patients (age 18-65). Fluent in English. Epilepsy patients with poorly controlled (>=2 seizures per week). Focal onset seizures. Seizure onset zone in the mesial temporal or neocortical onset as determined by >2 concordant criteria, without discordant criteria (semiology, MRI Brain, and EEG). Able to give informed consent.  Exclusion criteria:  Patients with skull defects. Patients with implanted neurostimulator or other implanted cerebral hardware. Patients with multifocal onset epilepsy. Patients who are non-verbal or incapable of providing informed consent. Current substance abuse. Pregnancy. Patients with non-MRI compatible implants (for Experiments 2 and 3).