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Insomniac Flies May Provide Clues to Human Sleep Disturbances

Scientists at the Washington University School of Medicine have created a line of fruit flies that sleeps for less than one tenth the time of normal fruit flies (one hour versus twelve hours). "Insomnia is a common and debilitating disorder that results in substantial impairments in a person's quality of life, reduces productivity, and increases the risk for psychiatric illness," said senior author Dr. Paul Shaw. "We think this model has clear potential to help us learn more about the causes of insomnia and someday develop ways to test for or treat them in the clinic." Earlier, Dr. Shaw’s lab had been the first to show that fruit flies enter a state of inactivity comparable to sleep. The researchers demonstrated that the flies have periods of inactivity during which greater stimulation is required to rouse them. Like humans, flies deprived of sleep one day will try to make up for it by sleeping more the next day. In the current work, the researchers created the line of “insomniac” flies by selective breeding of flies that naturally exhibited certain insomnia-like signs. These included difficulty in falling asleep under normal circumstances, and sleep that was often interrupted or fragmented. The researchers also used hyper-responsiveness to stimuli as a breeding guide. For example, if researchers turned on a light at night, insomniac flies woke and stayed up the rest of the night, while the healthy flies went back to sleep. The flies that stayed up were added to the breeding pool. Ultimately, this selective breeding resulted in a line of flies that sleeps for only one hour a day. This work will be published in the June 3 issue of the Journal of Neuroscience. [Press release]