2. Depth catheter/electrode placement into the presumed location of the seizure focus (the part of the brain where the seizures originate) - A small hole is drilled through the skull. A depth electrode with a hole in the center of the tubing is passed through the brain into the structures usually involved in intractable epilepsy. MRI will be done to check electrode placement. Video-EEG monitoring will continue for 5 days for this part of the study. Patients will be tested for their ability to understand and produce speech, see normally, move their arms and legs, distinguish sharp and dull objects, and put pegs in a pegboard. They will be questioned about headache, weakness, numbness or sleepiness. The electrode will be left in place for muscimol infusion (see #3).