Sleep and General Anesthesia Clear the Mouse Brain of Toxic Metabolites

Without sufficient sleep, mood and cognition are impaired. Various central nervous system conditions, including migraines and seizures, become more frequent and severe. When animals are kept from sleeping, they ultimately die.

We need to sleep. But why? Investigators from New York developed a technique for measuring the interstitial space in the brains of living mice. That space is bathed by cerebrospinal fluid that is produced by the choroid plexus and pumped back into the blood in the meninges. The investigators found that, during sleep and anesthesia, the interstitial space increased by 60%. The functional result of this expansion is that many metabolites of neurons and glial cells that spill into the interstitial space are cleared from t…