[1] Univ Louisville, Dept Neurol Surg, Louisville, KY USA
[2] Univ Louisville, Kentucky Spinal Cord Injury Res Ctr, Louisville, KY USA
[3] Univ Louisville, Comparat Med Res Unit, Louisville, KY USA
[4] Robley Rex VA Med Ctr, Louisville, KY 40202 USA
[5] Univ Louisville, Kentucky Spinal Cord Injury Res Ctr, 511 S Floyd St,Med Dent Res Bldg, Louisville, KY 40202 USA