Interesting write up in Washington Post this morning about a new study just published in Science.
During sleep, our brain cells shrink, opening gaps in between the cells, which allows extremely efficient circulation of "cerebrospinal fluid throughout the brain tissue and flushing any resulting waste into the bloodstream, which then carries it to the liver for detoxification."
The circulation clears this waste, including "beta-amyloid protein, clumps of which form plaques found in the brains of Alzheimer’s patients."