1. Department of Neurology, University of California at San Francisco, Mission Bay, 1550 Fourth Street, San Francisco, CA 94158, USA.
2. Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA.
3. Sleep and Circadian Neurobiology Laboratory, Stanford University, 1201 Welch Road, P213, Palo Alto, CA 94304, USA.
4. Mechanical Engineering, University of California, Berkeley, Hesse Hall, Room 245, Berkeley, CA 94720, USA.
5. Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.