What are the mechanisms that control sleep?

     Each night, we grow tired and enter sleep, a behavioral state in which we are largely disengaged from the external world. Humans and other animals have been sleeping for millions of years, yet both the purpose of sleep and the mechanisms that control this fundamental behavior remain poorly understood. Understanding these mechanisms is important, given that sleep is integral to human health and that disruptions of sleep are associated with physiological and neurological disorders.

     Sleep is an evolutionarily ancient behavior, and most animals that have been examined have a sleep state. Among these animals is the fruit fly, Drosophila melanogaster, an evolutionary cousin of humans and a model organism long favored by biologists due to its powerful genetic tools. By using the fly to identify mechanisms that control sleep, our studies have the potential to reveal fundamental biological mechanisms shared by other animals and to impact the diagnosis and treatment of human sleep disorders.