Your Brain Only Washes Itself While You Sleep
In short: The glymphatic system is the brain's own waste-clearance network, documented in 2012–2013 by Maiken Nedergaard's team at the University of Rochester. Cerebrospinal fluid flows in alongside arteries, passes through water gates called aquaporin-4 on glial cells, picks up waste such as beta-amyloid, and drains out along veins. In mice, that wash ran about twice as fast during sleep — and the honest caveat is that scientists are still arguing about exactly how much cleaning sleep accomplishes. The Brain Was Thought to Have No Sewer The body drains cellular debris through the lymphatic system, but for over a century anatomists searched the brain for lymph vessels and found none — so textbooks declared the brain had no lymphatic drainage. That is strange: the brain is about two percent of body weight yet burns roughly a fifth of your energy. A factory with no sewer. The clear cerebrospinal fluid it floats in — about a cup at any moment in a human, replaced several times ...