1. Behavioral Sciences Laboratories, Veterans Affairs Medical Center, Oklahoma City, OK, USA;
2. Department of Psychiatry and Behavioral Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA;
3. Department of Psychiatry, University of Arkansas for Medical Sciences, Little Rock, AK, USA;
4. Cognitive Science Research Center, University of Oklahoma, Norman, OK, USA;
5. Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA