New research provides clues to falling fast asleep – or lying wide awake. Studying fruit flies, the researchers found that brain neurons adapt to help the flies stay awake despite tiredness in dangerous situations and help them fall asleep after an intense day. The findings, from Washington University School of Medicine in St. Louis and the University of Missouri, Kansas City, are published online in PLoS Biology, and could lead to new approaches to treating insomnia and improving sleep quality in people.
“If you’re sick or sleep deprived, or you’ve just learned something new, you sleep more,” said co-corresponding author Paul Shaw, PhD, a professor of neuroscience at Washington University. “But if something dangerous is happening, your brain says, ‘No, no, no, no. It’s not time to go to sleep. I don’t care how tired you are.’ The neurons that regulate sleep can tell the difference between sleep when it’s safe and sleep when it’s dangerous.”
The sleep habits of fruit flies are a lot like ours. The flies are active in the day, sleep at night, and like to take a little nap in the afternoon, particularly on hot days. Caffeine keeps them up, and drugs that put us to sleep work on flies, too.
There is one crucial difference, though: Their brains are a million times smaller than ours, making it possible to identify the role each neuron plays in controlling fly behavior. Shaw and co-corresponding author Stephane Dissel, PhD — an assistant professor of biological sciences at the University of Missouri who began working on this project while a postdoctoral researcher at Washington University — focused on 24 brain neurons that control whether a fly sleeps or wakes.