1. Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky.
2. Department of Physiology, University of Kentucky, Lexington, Kentucky.
3. Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, Kentucky.
4. Department of Biomedical Imaging, University of Kentucky, Lexington, Kentucky.
5. Department of Anatomy and Neurobiology, University of Kentucky, Lexington, Kentucky.