People are freaking out after learning what could happen to our brain during sleep

A study has revealed what may happen in your brain when you sleep and it's blowing people's minds.

You may've already learnt about why your body sometimes jerks as you fall asleep or what AI depicts our dreams to really look like, but do you know what biologically goes on in your brain as you drift into slumber and why one social media user has claimed 'brainwashing is real'?

The aim

A study led by researchers from Boston University - first published on 31 October, 2019 in Science News - sought to figure out how the brain's cerebrospinal fluid (CSF) moves alongside its neural activity when someone is asleep.

Neural activity helps us consolidate and process memories whereas CSF 'clears metabolic waste products from the brain,' the study notes.

Cerebrospinal fluid also 'flows in and around the brain and spinal cord to help cushion them from injury and provide nutrients,' as per the National Cancer Institute.

The study explains: "Whether these two processes are related is not known. We used accelerated neuroimaging to measure physiological and neural dynamics in the human brain."

The study saw participants go to sleep in an MRI machine (CFOTO/Future Publishing via Getty Images)

The study

For the study, 13 people aged between 23-33 were recruited to lie inside an MRI machine and go to sleep.

The MRI machine then captured images of the participants' brains' CSF.

And the images revealed your brain is a lot more active than you may realize when you rest your head on your pillow and attempt to nod off and get your eight hours.

Images of the brain were captured for researchers to analyse how blood and cerebrospinal fluid moved while the person was sleeping (Laura Lewis, N. Fultz et al/Science 2019)

The results

The images revealed that during 'non-rapid eye movement sleep, a.k.a. non-REM sleep, there's not only 'slow neutral activity' but that this activity is followed by 'brain-wide pulsations in blood volume and CSF flow'.

Basically, a wave of fresh CSF goes into the brain and washes out any harmful proteins - such as those which can increase the risk of Alzheimer's disease - 'every 20 seconds' - the pattern reviewed as 'striking' by Boston University neuroscientist and engineer and co-author on the study Laura Lewis.

The frequency of the pulsations of CSF into the brain has addressed 'a key missing link in the neurophysiology of sleep' and emphasized just how important sleep is to clearing the brain.

Lewis resolved: "It’s such a dramatic effect. [CSF pulsing during sleep] was something we didn’t know happened at all, and now we can just glance at one brain region and immediately have a readout of the brain state someone’s in."

And it's not taken long for people to flood to social media in awe of the study's results, but also slightly freaked out by their brain basically going through it's own equivalent of a washing machine cycle.

The CSF (blue) helps clear out 'harmful proteins' from the brain (Laura Lewis, N. Fultz et al/Science 2019)

A Reddit user u/douggold11 took to r/todayilearned earlier today (21 July) to share news of the study.

U/PRRZ70 wrote: "So brains take a 'shower' when we're sleeping? Nice."

"Well, your brain is always surrounded by CSF, so I think it's more like someone who has spent too long in the bath, but doesn't want to get out...cracking the drain a bit while they pour in fresh water...," u/OneBigBug responded.

U/unaccomplishedBat889 commented: "Mhm, make that brain squeaky clean."

And u/Combat_Armor_Dougram resolved: "So brainwashing is real."

However, it's important to note another study has contradicted the 2019 experiment's findings, a test on mice finding 'brain clearance' is actually 'reduced during sleep'.

Although, the study - published May 2024 in Nature Neuroscience - ultimately resolves: "How metabolites and toxins are cleared from the brain is unresolved."