1. Department of Physiology, University of Kentucky, Lexington, KY, USA
2. Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA
3. Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, USA
4. Department of Statistics, University of Kentucky, Lexington, KY, USA
5. Department of Neuroscience, University of Kentucky, Lexington, KY, USA
6. Lexington Veterans’ Affairs Healthcare System, Lexington, KY, USA