When you’re asleeping, you’re really brainwashed.

Red is blood, blue is cerebrospinal fluid. Scientists at Boston University, for the first time, photographed the cleansing process:

It’s never been seen before that blood periodically floods out of the brain. Whenever it does, the cerebrospinal fluid launches an “attack” that removes toxins like amyloid beta, the protein that causes Alzheimer’s disease.

Such cleansing can only be done after sleep, so that people wake up with a fresh brain; not asleep, cerebrospinal fluid and not enough opportunity to “take advantage of the empty.”.

In addition, the researchers also found a relationship between brain electrical activity and cleaning process, that is, brain waves command fluid movement.

This achievement, just went up science. So, sleep a bit more, did not stay up late. “Brainwash” wash not over, perhaps really can become silly.

How the hell did you get rid of it?

In one experiment, scientists had 13 people wear EEG caps and sleep in an MRI machine. The EEG shows which sleep state a person is in, while the MRI measures blood oxygen levels and shows how much cerebrospinal fluid is flowing in and out.

And then there’s the wonderful thing: there’s a big, periodic change in the blood oxygen concentration in the brain. That is, there’s a massive, periodic flow of blood out of the brain.

At this time, cerebrospinal fluid will take the opportunity to rush into the brain and fill up the space left for it.

After waking up, the big cycle is gone, and the cerebrospinal fluid can’t rush into the brain in large quantities to complete an effective cleaning.

Laura Lewis, the corresponding author of the paper, believes that this is because during sleep, neurons in the brain begin to synchronize their activities, opening and closing together.

The reason for this speculation is that EEG data show that the circulation of blood and cerebrospinal fluid occurs only after the emergence of neural rhythms.

When a large number of neurons stop firing together, less blood is needed to carry oxygen, giving the opportunity for cerebrospinal fluid to flood in.

Why only sleep can “brainwash”

This finding is important because it tells us that sleep is a very special function:

Neurons Don’t open and close together when we’re awake, so there’s no way to get the brain’s blood flow down to a low enough level when we’re awake.

Only after sleep, when there is not so much blood in the brain, can the cerebrospinal fluid circulate freely and remove by-products of metabolism such as beta-amyloid protein.

Stay up a little less.

“Brainwashing” can’t be finished, and maybe it will really become stupid.