Sleep is ubiquitous across the animal kingdom — all species assessed to date show some kind of sleep state. But no one knows the precise purpose of sleep. “Why does every neural network need some relaxation?” asks Manuel Zimmer, a neuroscientist at the Research Institute of Molecular Pathology, in Vienna, and an investigator with the Simons Collaboration on the Global Brain. “Neuroscience has a lot of good hypotheses but not a unifying clear-cut answer to why that’s the case.”
Zimmer and collaborators aim to chip away at this question using newly developed techniques to monitor the whole brain in the microscopic round worm C. elegans as it falls asleep and wakes up. “That makes it possible to watch how the brain switches between these drastically different states,” Zimmer says.