1. Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
2. Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
3. Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
4. Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut, USA
5. Department of Diagnostic Radiology, Yale University, New Haven, Connecticut, USA
6. Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA