How Deep Sleep May Help the Brain Clear Alzheimer's Toxins

A study published in Science suggests brain waves produced in deep sleep may activate a system that purges toxins associated with Alzheimer's and other neurodegenerative diseases, reports National Public Radio . These so-called slow waves appear right before a pulse of cerebrospinal fluid (CSF) goes through the brain, presumably washing away such toxins. Boston University Professor Laura Lewis said this discovery could explain the connection between sleep and Alzheimer's, specifically how "some disruption to the way sleep is working could potentially be contributing to the decline in brain health." University of California, Berkeley Professor William Jagust added that the study's results hint at how people might be able to cut their risk of Alzheimer's by ensuring they receive high-quality sleep. Lewis and colleagues used advanced magnetic resonance imaging and other technologies to monitor brain activity in 11 sleeping people. The team observed waves of CSF washing into the brain in 20-second intervals, preceded by a wave of electrical activity in the neurons. The implication is that the electrical wave is somehow triggering this "wash cycle." In addition, blood flow decreases as the CSF flow increases, which leaves more room for CSF to carry off waste.