1. Department of Neurology, Program in Sleep, Emory University School of Medicine, Atlanta, GA 30322, USA.
2. Emory University School of Nursing, Atlanta, GA 30322, USA.
3. Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
4. Anesthesiology and Research Divisions, Atlanta VA Medical Center, Atlanta, GA 30033, USA.
5. Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA.
6. Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA.
7. Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA.