PowerPoint Presentation - SLEEP: Why? When? How? DISORDERS: narcolepsy, apnea, sleep time syndrome, jet lag, many others DO WE GET ENOUGH SLEEP? IF NOT, WHAT ARE THE CONSEQUENCES? Students/fellows/scientists/truck drivers/pilots/astronauts RELATION TO CIRCADIAN RHYTHM David Dinges, PhD U.Penn: Director, Unit Exp. Psychiatry; Chief, Division of Sleep and Chronobiology (Psychiatry); Assoc. Director, Center for Sleep and Neurobiology. Many, many awards, leadership positions, publications and Editor, SLEEP This page uses frames, but your browser doesn't support them.