In this study, an array of micro-electrodes will be inserted into the brain of patients with epilepsy while they are undergoing a clinically indicated assessment with intracranial electroencephalography (EEG). The micro-electrode array is able to continuously record the activity of neurons in the human brain. In combination with the standard intracranial EEG, the recordings of the micro-electrode array will allow a better understanding of the relationship between epileptic seizures and the activity of neurons.