David M. Holtzman, M.D., of Washington University in St. Louis uncovered a link between sleep deprivation and Alzheimer’s disease. Holtzman found that amyloid plaques appeared earlier and more frequently in the brains of mice deprived of sleep than in mice with normal sleep patterns. The study also pointed to orexin, a neurotransmitter that regulates the sleep cycle, as likely being involved in the production of increased levels of amyloid. This research helped both to identify orexin as a potential drug target, and to demonstrate the critical importance of adequate sleep in lowering risk for Alzheimer’s disease.