1. Neuroscience Graduate Program, Department of Neuroscience, Carney Institute for Brain Science, and School of Engineering, Brown University, Providence, RI 02912, U.S.A.; and Department of Surgery (Neurosurgery), Dalhousie University, Halifax, NS B3H 347 Canada
2. Division of Applied Mathematics, Brown University, Providence, RI 02912, U.S.A.
3. Center for Neurotechnology and Neurorecovery, Neurology, Massachusetts General Hospital, Boston, MA 02114, U.S.A.
4. Center for Neurorestoration and Neurotechnology, Rehabilitation R&D Service, Department of Veterans Affairs Medical Center, Providence, RI 02908; Carney Institute for Brain Science and School of Engineering, Brown University, Providence, RI 02912; Center for Neurotechnology and Neurorecovery, Neurology, Massachusetts General Hospital, Boston, MA 02114; and Neurology, Harvard Medical School, Boston, MA 02115, U.S.A.