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  • Bad news for all of us insomniacs out here, but as we do more research into the brain,

  • were increasingly realizing that sleep is one of the most essential things we need

  • to be functioning, healthy human beings.

  • And new research looks into how sleep helps us maintain clean brains, but what does that mean?

  • And why is it that important?

  • Well to understand this latest news, we have to go back to 2013, when a study of mouse brains

  • found that while those furry, little rodents slept, neurotoxic waste products got swept away.

  • Some kind of cleaning crew comes in overnight and gets rid of built up stuff like beta amyloid,

  • that sticky peptide that can aggregate into plaques and disrupt brain function.

  • Amyloid plaques are highly associated with the occurrence of diseases like Alzheimer’s,

  • and theamyloid hypothesissuggests that amyloid plaques could be the primary

  • cause of that devastating disease.

  • So it’s real nice that your brain can get rid of it while you sleep.

  • That 2013 study saw an interesting relationship.

  • While the mice slept, their glymphatic systems opened up.

  • This let in a big wash of cerebrospinal fluid, or CSF, which seemed to clear these waste

  • products away.

  • And just so you know, CSF is a watery, clear substance that surrounds your brain and spinal

  • cord and acts kinda like a little cushion to protect your brain, and provide it with nutrients.

  • A team at Boston University took this 2013 finding and wanted to know exactly how.

  • In this new study they published in Science, the researchers delved into what about sleep

  • was so special.

  • Why did a sleep state in particular allow for these changes in the brain?

  • The team got human participants to fall asleep inside an fMRI machine, which is seems like

  • quite a feat in itself, and which let the team measure both the blood oxygen levels in the participants

  • brains and show the flux of cerebrospinal fluid.

  • They also measured the electrical currents in subjectsbrains using an EEG cap.

  • The results gave the team a pretty clear answer, one that came in waves.

  • Weve been finding out more over the past several years about the phases our brains

  • go through while we sleep, and how those phases are essential to information processing and

  • memory formation.

  • And it turns out, it’s not just during rapid-eye-movement or REM sleep that our brains are consolidating

  • information and committing it to our long-term memory, but theyre doing it during nonREM too.

  • And in humans, these two states of sleepREM and nonREMalternate throughout the night.

  • Non-REM sleep is divided into 3 stages, and that third stage is our deepest state of sleep,

  • called slow wave sleep.

  • During slow wave sleep, electrical activity slows down and syncs up.

  • So our neurons start to fire in sync with one another at quite a slow frequency that

  • neuroscientists call delta waves.

  • And while slow wave sleep has been shown to be essential to memory formation, this latest

  • study is the first to demonstrate exactly how those slow waves keep our brains clean

  • and healthy.

  • From all of their many measurements, the Boston team saw that during slow wave sleep, the

  • brain was actually being washed by waves of cerebrospinal fluid,

  • like a free nighttime spa for your brain.

  • See, when neurons start to fire in sync theyre all electrically active at the same time,

  • and that means there’s empty time in between activity.

  • When those neurons aren’t firing, they need less oxygen, so less blood is flowing to the

  • brain.

  • But cerebrospinal fluid comes in and fills in that extra space!

  • So this pattern in CSF flow is intrinsically linked to neuron firing.

  • The neurons light up, the neurons go dark, the CSF comes in, the CSF goes out.

  • It’s all very relaxing.

  • This study not only found a direct relationship between electrical activity in the brain and

  • this CSF cleansing mechanism, but also confirmed that an increase in CSF is linked to increased

  • clearing of neurotoxic waste products like beta amyloid.

  • This indicates that sleepand slow wave sleep in particularis essential to clearing

  • out all the gunk in your brain.

  • Your brain garbage, if you will.

  • And the thing iswe still don’t understand a whole lot about neurodegenerative diseases

  • like Alzheimer’s.

  • We know that we see these build-ups of amyloid plaques, we know that a protein called tau

  • causes damage to neurons, but so far, our forays into developing treatments that target

  • those variables haven’t been very fruitful.

  • So improved understanding, like this new study provides of how the brain clears out toxic

  • buildup naturally, could help us combat neurodegenerative diseases

  • in novel and innovative ways.

  • Plus, it’s just huge inspiration to get better sleep, and more of it.

  • I’m gonna get right on that.

  • If you want to learn more about Alzheimer’s, check out this video here from our series

  • Sick, and make sure you subscribe to Seeker for all your neuroscience updates.

  • If you have another brain question in mind that you want us to cover, let us know down

  • in the comments below and as always, thanks for watching.

  • I’ll see you next time.

Bad news for all of us insomniacs out here, but as we do more research into the brain,

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科學家發現睡眠如何清除大腦中的毒素? (Scientists Discovered How Sleep Cleans Toxins From Your Brain)

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    林宜悉 發佈於 2021 年 01 月 14 日
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