1Departments of Neurological Surgery and Physiology, University of California, San Francisco, San Francisco, California 94143-0112,
2Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, California 94158,
3Center for Neural Engineering and Prosthesis, University of California, San Francisco and University of California, Berkeley, Berkeley, California 94720-3370, and
4UCSF Epilepsy Center, University of California, San Francisco, San Francisco, California 94143