介绍： 2 One more reason to get a good night's sleep
一定要睡个好觉——有一个重要的原因

TED：2014
Speaker:Jeff Iliff，Neuroscientist.

00:00
and what’s amazing is that no other organ takes quite this approach to clearing away the waste from between its cells.this is a solution that is entirely unique to the brain...

介绍： 2 One more reason to get a good night's sleep
一定要睡个好觉——有一个重要的原因

TED：2014
Speaker:Jeff Iliff，Neuroscientist.

00:00
and what’s amazing is that no other organ takes quite this approach to clearing away the waste from between its cells.this is a solution that is entirely unique to the brain.but our most surprising finding was that all of this,everything I just told you about,with all this fluid rushing through the brain,it’s only happening in the sleeping brain.here,the video on the left shows how much of the CSF is moving through the brain of a living mouse while it’s awake.it’s almost nothing.yet in the same animal,if we just a little while until it’s gone to sleep,what we see is that the CSF is rushing through the brain,and we discovered that at the same time when the brain goes to sleep,the brain cells themselves seem to shrink,opening up spaces in between them,allowing fluid to rush through and allowing waste to be cleared out.so it seems that Galen may actually have been sort of on the right track when he wrote about fluid rushing through the brain when sleep came on.our own research,now it’s 2,000 years later,suggests that what’s happening is that when the brain is awake and is at its most busy,it puts off clearing away the waste from the spaces between its cells until later,and then,when it goes to sleep and doesn’t have to be as busy,it shifts into a kind of cleaning mode to clear away the waste from the spaces between its brain ,the waste that’s accumulated throughout the day.

so it’s actually a little bit like how you or I,we put off our household chores during the work week when we don’t have time to get to it,and then we play catch up on all the cleaning that we have to do when the weekend rolls around.now,I’ve just talked a lot about waste clearance,but I haven’t been very specific about the kinds of waste that the brain needs to be clearing during sleep in order to stay healthy.the waste product that these recent studies focused most on is amyloid-beta,which is a protein that’s made in the brain all the time.my brain’s making amyloid-beta right now,and so yours.but in patients Alzheimer’s disease,amyloid-beta builds up and aggregates in the spaces between the brain’s cells,instead of being cleared away like it’s supposed to be,and it’s this buildup of amyloid-beta that’s thought to be one of the key steps in the development of that terrible disease.so we measured how fast amyloid-beta is cleared from the brain when it’s awake versus when it’s asleep and and we found that indeed,the clearance of amyloid-beta is much more rapid from the sleeping brain.

so sleep,then,is part of the brain’s solution to the problem of waste clearance,then this may dramatically change how we think about the relationship between sleep,amyloid-beta,and Alzheimer’s disease.a series of recent clinical studies suggest that among patients who haven’t yet developed AIzheimer’s disease,worsening sleep quality and sleep duration are assocaater with a greater amount of amyloid-beta building up in the brain,and while it’s important to point out that these studies don’t prove that lack of sleep or poor sleep cause AIzheimer’s disease,they do suggest that the failure of the brain to keep its house clean by clearing away like amyloid-beta may contribute to the development of conditions like AIzheimer’s.so what this new research tells us,then,is that the one thing that all of you already knew about sleep,that even Galen understood about sleep,that it refreshes and clears the mind,may actually be a big part of what sleep is all about.see,you and I,we go to sleep every single night,but our brains,they never rest.while our body is still and our mind is off walking in dreams somewhere,the elegant machinery of the brain is quietly hard at work,cleaning and maintaining this unimaginably complex machine.like our housework,it’s a dirty and a thankless job,but it’s also important.in your house,if you stop cleaning your kitchen for a month,your home will become completely unlivable very quickly.

but in the brain,the consequences of falling behind may be much greater than the embarrassment of dirty counter-tops,because when it comes to cleaning the brain,it is the very health and function of the mind and the body that’s at stake,which is why understanding these very basic housekeeping functions of the brain today may be critical for preventing and treating diseases of the mind tomorrow.

thank you.