[1] Univ Calif Los Angeles, David Geffen Sch Med, Dept Neurosurg, Los Angeles, CA 90095 USA
[2] Univ Calif Los Angeles, Brain Res Inst, Los Angeles, CA 90095 USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Dept Orthoped Surg, Los Angeles, CA 90095 USA
[4] Univ Calif Los Angeles, David Geffen Sch Med, Neuromotor Recovery & Rehabil Ctr, Los Angeles, CA 90095 USA
[5] Univ Calif Los Angeles, David Geffen Sch Med, Dept Radiol Sci, Los Angeles, CA 90095 USA
[6] Hosp Special Surg, Dept Radiol, New York, NY 10021 USA