Australasian Science: Australia's authority on science since 1938

To Sleep, Perchance to Clean the Brain

By Tim Hannan

The restorative function of a night’s sleep may result from elimination of the day’s neurotoxins.

The full text of this article can be purchased from Informit.

While those who mark World Sleep Day are probably disinclined to do so with all-night parties, neuroscientists may have celebrated it this year more enthusiastically with the news that one of biology’s great mysteries may have been solved.

Despite advances in understanding the architecture and neurobiology of sleep, a satisfactory answer to the question of why humans and other animals sleep had long proven elusive. Now, a new study has found evidence for the proposition that sleep facilitates the removal of potentially toxic products in the brain – that is, that the brain cleans itself while we sleep.

Like most animals, humans operate on a daily cycle of alternating activity and sleep, and it is evident that sleep serves a restorative function of some kind: the need to sleep increases with time since its last occurrence, and generally people do not function well without sleep.

It is well-established that sleep deprivation is associated with impaired performance on cognitive tests, including a longer reaction time to stimuli, and that prolonged deprivation may result in progressively worsening cognition and even death. Yet precisely how sleep is restorative, and why the lack of sleep impairs brain function, has remained unknown.

In the study published in Science, a team of American researchers investigated the hypothesis that sleep enhances the...

The full text of this article can be purchased from Informit.