1. Department of Physics and Astronomy, University of Georgia Franklin College of Arts and Sciences, Athens, Georgia, USA.
2. University of Georgia Bio-Imaging Research Center, Athens, Georgia, USA.
3. Department of Psychology, University of Georgia Franklin College of Arts and Sciences, Athens, Georgia, USA.
4. Georgia Prevention Institute, Medical College of Georgia, Augusta, Georgia, USA.
5. Department of Radiology and Imaging, Medical College of Georgia, Augusta, Georgia, USA.