Study subjects are neurosurgical patients with medically refractory epilepsy who will have implanted with intracranial ECoG electrodes. The electrodes will be used during a period of inpatient monitoring to identify resectable seizure foci.

EEG will be collected with Brain Product's VAMP-16 channel EEG Monitor using the accompanying software. (Website with further specifications and product details: https://www.brainproducts.com/productdetails.php?id=15)

Patient subjective level of consciousness during and after anesthesia administration will be assessed using response to verbal stimuli, response via button press, reported subjective level of consciousness, and/or response to memory tests (i.e. demonstration of explicit memory recall). Around loss and recovery of consciousness time points (e.g. induction or emergence from anesthesia or when patient falls asleep or wakes up during 24 hour postoperative time points) level of consciousness will be assessed in brief intervals (seconds) until patient no longer responds or begins to respond. Data collected before, after, and during seizure activity if a patient loses consciousness or has diminished consciousness may also be compared.

Scalp and cortical electrical activity collected using EEG and ECOG arrays respectively will be analyzed using standard frequency-derived measures (e.g. spectrograms, Fourier analysis), nonlinear dynamical analyses (e.g. correlation dimension, entropy), network dynamics (e.g. connectivity matrices, path length), and/or machine learning. These measures will include all of the data collected from the start of the implant procedure until 24 hours after the implant procedure has ended. Data collected before, after, and during seizure activity if a patient loses consciousness or has diminished consciousness may also be compared. Reports will included characterization of electrophysiological activity before, during, and after variations in behavioral and subjectively reported consciousness.