1. Department of Behavioral Science, University of Kentucky College of Medicine, Lexington, KY, USA
2. Department of Psychiatry, University of California, San Francisco, CA, USA
3. Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
4. Department of Neurology, University of Kentucky College of Medicine, Lexington, KY, USA
5. Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, USA
6. Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky College of Medicine, Lexington, KY, USA
7. Oak Ridge National Laboratory, Oak Ridge, TN, USA