1. Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville, Louisville, Kentucky.
2. Frazier Rehab Institute, Louisville, Kentucky.
3. Department of Neurology and Brain Research Institute, University of California, Los Angeles, California.
4. International Collaboration on Repair Discoveries (ICORD), Division of Physical Medicine and Rehabilitation, and School of Rehabilitation, Department of Medicine University of British Columbia, and Spinal Cord Injury Program, G.F. Strong Rehabilitation Centre, Vancouver, British Columbia, Canada.