1. Department of Anatomy and Neurobiology, College of Medicine, University of California, Irvine, California
2. Department of Physical Medicine and Rehabilitation, College of Medicine, University of California, Irvine, and Spinal Cord Injury/Disorders Healthcare Group, Long Beach V.A. Medical Center, Long Beach, California
3. Department of Physical Medicine and Rehabilitation, College of Medicine, University of California, Irvine, and Spinal Cord Injury/Disorders Healthcare Group, Long Beach V.A. Medical Center, Long Beach, California