A.M. and P.M. Clocks: Fruit fly brain has double timekeepers

A fruit fly relies on a different group of cells to tick out the rhythm to perk up in the morning than it does to boost evening activity after daytime doldrums, report two research teams.

Both teams performed experiments that altered the functions of cell clusters in each fly-brain hemisphere. Although the investigators, one team in France and the other in the United States, took different approaches, both groups pinpointed the same clusters of neurons for the morning- and the evening-activity increases.