A remarkable change occurs in our brains each night, making us lose the essence of who we are for hours at a time: we fall asleep. A process so familiar to us, sleep nevertheless remains among the most mysterious phenomena in biology. The goal of Dragana Rogulja’s work is to understand how the brain reversibly switches between waking and sleep states, and why we need to sleep in the first place.
To address these questions, she is using Drosophila melanogaster as her model system, because sleep in the fly is remarkably similar to mammalian sleep. Flies have consolidated periods of activity and sleep; arousal threshold is elevated in sleeping flies; the brain’s electrical activity differs between sleeping and awake flies. As in people, both circadian and homeostatic mechanisms provide input into the regulation of fly sleep: flies are normally active during the day and quiescent at night, but if deprived of sleep will show a consequent increase in “rebound” sleep, regardless of the time of day.