The Weird Thing Your Brain Can Be Doing While You Sleep

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While you sleep, your brain is removing wasteSleep—ah, perchance to dream! Perhaps you’ve said that lament to yourself on many nights when sleep just wouldn’t come. Insomnia—when it strikes—can leave your life in turmoil as you struggle to function normally. Everything seems harder, from walking up a flight of stairs, to driving and carrying on a conversation.

Why does lack of sleep have such a drastic effect on our ability to think and concentrate? A new study has revealed some surprising clues about just exactly what happens in your brain while you sleep.

According to lab experiments conducted on mice, there are not-so-subtle changes that take place in your brain when you are in a deep slumber.

Cellular waste that accumulates all day long is cleaned out of your brain once you fall asleep. It seems cerebral spinal fluid is pumped into your brain. But wait—wouldn’t all this extra fluid sloshing around in your brain exert an adverse effect? According to the researchers (based at Oregon Health and Science University and New York University) who published their study results in the journal Science, the brain actually shrinks by about 60% when asleep. This extra space creates room for the fluid which can then circulate and carry away all the waste products that have lodged themselves in and around brain cells.

These waste products include amyloid-beta plaques which have been linked to the onset of Alzheimer’s and other forms of dementia.

Where do these waste products go? They are carried out in the brain’s own blood vessels and deposited in the circulatory system. From there, this potentially harmful waste makes its way to the liver.

All of this action—the shrinking of the brain and whisking away of harmful substances—happens in an area of the brain called the glymphatic system. The researchers noted that the glymphatic system is 10 times more active when someone is asleep compared to when awake.

So why doesn’t your brain perform these housekeeping duties while you’re awake? Your brain is only allotted a certain amount of energy to use and because it has so many jobs to perform while you’re awake, the only time it can divert energy to removing wastes is while you’re asleep.

These findings show that it may be important for those with dementia and other brain disorders to get lots of quality sleep every night. In fact, sleep may be the one “therapy” that could really make a difference as far as disease progression and further damage to the brain goes.

Scientists have long known that sleep deprivation exerts adverse effects on the waking brain and body. But what they have never quite figured out is the basic purpose of sleep. Many have suggested that it’s a chance for the body to conserve energy. Others say sleep is needed to process accumulated memories from the day, while others think sleep gives the body a chance to regulate all of its functions.

With the results of this study, scientists will now be focusing on the housekeeping duties of the body during sleep, and your body’s very own waste removal system, and may one day decide that this is the real primary purpose of getting some shut-eye every night.

Source(s) for Today’s Article:
Xie, L., et al., “Sleep drives metabolite clearance from the adult brain,” Science. October 2013; 342(6156): 373-7.
Underwood, E., “Neuroscience. Sleep: the brain’s housekeeper?” Science. October 18, 2013; 342(6156): 301.
Herculano-Houzel, S., “Neuroscience. Sleep it out.” Science. October 18, 2013; 342(6156): 316-7.