BBC News, science reporter, 17 October 2013
Summary of the above report
A reearch team has suggested that at least one function of sleep is to allow waste removal from the brain. A report in ‘Science’ describes glial cells in the brain as shrinking during sleep, so as to allow fluids to wash between neurons. What is now referred to as the glymphatic system has recently been discovered as a method of cleaning the brain, and it has been demonstrated to be 10x more active during sleep than during waking. Energy constraints are thought to make it difficult for the brain to function in an awake state and cleanse itself at the same time. The clearance of some harmful proteins is viewed as important, and it is suggested that failure to carry this out may be a factor in some brain disorders.