In a paper to be published June 8 by the journal Nature, a team led by Ravi Allada, assistant professor of neurobiology and physiology, shows that the so-called mushroom bodies are essential for sleep regulation in the fruitfly Drosophila melanogaster. (In the same issue, a second study, led by Amita Sehgal of the Howard Hughes Medical Institute, produced similar results using different methods.)
How the mushroom bodies control sleep is uncertain, but Allada and colleagues show that if the area is destroyed chemically, flies sleep less.
Mushroom bodies are known to have a role in learning and memory, raising the possibility that sleep and learning are somehow linked in the fly brain. This lends weight to the notion that, in flies, sleep may function to consolidate memories that are formed during the day -- something that is known to occur in vertebrates.
Sleeping flies are similar to sleeping humans. Both are groggy when woken suddenly and need extra slumber if sleep deprived. It's therefore possible, the authors argue, that a mechanism regulating both sleep and learning could be evolutionarily conserved. So studying the mushroom bodies may help to throw light on the mechanisms governing vertebrate and invertebrate sleep.
In addition to Allada, other authors on the Nature paper are Jena L. Pitman (co-first author), Jermaine J. McGill and Kevin P. Keegan, all from Northwestern University.