The brain's waste clearing lymphatic system shown in people for first time

[PaulKeeble]

There have been a couple of papers [1] that can induce this process while awake using particular image patterns as confirmed in an MRI. I think the NIH confirmation is running behind in the science, independent research is quite a bit ahead of them. I came across the paper on this last year and implemented a very simple page with the parameters they used [2].

There is a number of disease models that show reduced or no glymphatic clearance and as such these people need treatments to clear out their brains and these image routines seem to help. A lot of people find this pattern extremely taxing to watch especially for the recommended number of cycles, you can feel the effect on the brain its hard to describe the sensation its a bit numbing and the image has the sensation of changing as the cycle runs like its a visual trick. You might get left feeling like you have been clubbed over the head the first time.

I find it interesting this is one aspect of disease research I am looking into and is related to Long Covid and ME/CFS.

[1] https://journals.plos.org/plosbiology/article?id=10.1371/jou...

[2] https://www.paulkeeble.co.uk/posts/cff/

[ClearAndPresent]

Paul's animation wasn't playing at an even rate for me, for some reason, so I created two video versions (8Hz and 12Hz) with the 16 second on/off period, starting with an off period, running for 254 seconds, as per the paper. These versions end with an an additional off period, as a 'cool down' from the flicker.

Framerate of 24Hz differs from the 120Hz as presented in the paper, but here there is no 40Hz flicker attempt so it shouldn't be an issue.

Compression may affect the edges of the lines, but downloads are enabled.

8Hz version - https://vimeo.com/1023278230/8ad6db6234

12Hz version - https://vimeo.com/1023275135/378186db55

[khafra]

This is some amazing work; and it also raises my belief that a Langford Basilisk is neurologically possible by about 25%

[haccount]

It is well established that visual patterns affect brain activity, this is used in clinical practice by neurophysiologists, put on an EEG cap and then do checkerboards, check if the activity is normal.

Now the question is if this provocation and resulting CSF flow is actually beneficial. Do you spike activity and get a rebound attempt at waste clearing due to waste accumulation of the neural spike, or is this like a massage for the brain that gives you a invigorating CSF dump?

I suspect it might not be a health improving activity. (I also suspect that you can get even more CSF flowing if you spin yourself at 6G in a full body centrifuge and that this too would not be conductive to health)

[hackernudes]

The paper says they used http://psychtoolbox.org/ to generate the images.

> Psychophysics Toolbox Version 3 (PTB-3) is a free set of Matlab and GNU Octave functions for vision and neuroscience research

Scientists almost never want to share their code and it makes me sad. Why wouldn't they want to make their paper more easily reproducible?

[feoren]

Staring at the v0.3 produces an effect similar to something I'm able to do trigger manually on command. I've always had the feeling that I'm somehow triggering a "flow" in my brain, but I have no way to confirm what's actually going on. It's actually stronger when I trigger it manually, and it feels like it flows down my spine and eventually some weak signal reaches my extremities. (Maybe that means it's not CSF after all?) Oddly, I do feel like I can think more clearly afterward, but the brain is very bad at judging itself, so it's more likely to be an illusion than anything real. Anyone else able to manually trigger a feeling like this in their brains?

[mettamage]

In me, there seemed to be an illusion going on. It felt like a tunnel and it felt as immersive as a "dream world" (albeit a bit of a boring one).

What I also noticed were the after image effects. A strong blue dot every time it flashed and circles divided into 8 sections like a star.

This was trippy.

[pedalpete]

The 40hz visual + auditory stimulation is showing to be surprisingly effective in mice and humans. [1] When I first heard this, I thought the open-loop nature, and the fixed frequency across subjects sounded improbable, but I'm happy to be proven wrong.

We work in the neurotech/sleeptech space doing slow-wave enhancement which, it is believed, increases glymphatic activity [2]. Recent studies have looked at the promise of alzheimer's prevention [3].

More links to research papers are on our website https://affectablesleep.com/science

[1] - https://www.nature.com/articles/s41586-024-07132-6 [2] - https://www.frontiersin.org/journals/neuroscience/articles/1... [3] - https://pmc.ncbi.nlm.nih.gov/articles/PMC10758173/

[flotzam]

Very cool! Five minutes of this felt strangely soothing in my head, after a few nights of not enough sleep.

Being able to set a max duration would be neat, in case it's unsafe to lose track of time and let the pattern run for too long?

Classic outdated comment BTW ;)

  setInterval(flickerImage, 250); // 8hz

[briankirby]

Thanks so much for creating and sharing this! Could you point me to any other independent research in this area? Also, as I read related journal articles, I'm trying to understand if the 40Hz sound is binaural (with a 40Hz difference between frequencies in each ear) or a straight 40Hz pulse (same in both ears). It's surprisingly hard for me to get a clear answer. Do you happen to have any experience with this or suggestions for related resources that might contain the answer? Thanks!

[jdthedisciple]

It seems to have no effect on me.

Am I an outlier?

[shaganer]

I wonder how this will work with hypophantic and aphantic individuals (people with little to no "mind's eye" visual imagery), such as myself. Like would the effect still be registered the same as anyone else, or would it cause the imagery effect to lessen or be ineffective altogether?

[physPop]

I work in this field —- You’re mis-construing the research a bit. Your reference talks about CSF flow on a more macroscopic scale (clearance out the fourth ventricle), which is fundamentally different than the glymphatic system referenced in the original story.

[kenjackson]

This is fascinating.

Curious, could seizures caused by strobe light be related to the effects of draining of this fluid?

[coxmi]

Clearing the waste sounds like a good thing, I guess. Haven't got time to read the study, but can this have beneficial effects to do while awake?

It certainly feels quite strange after watching the prototype for 8 cycles.

[jmpman]

I’d like to see if anyone with Fatal Familial Insomnia has been treated with this pattern. I expected that insomnia stops this glymphatic clearance, and that’s what eventually kills them.

[giantg2]

Wow, that is wild. I never would have thought that simply watching images would trigger something in the lymphatic system. This could have huge implications for multiple diseases.

[llm_trw]

Fascinating. Can you go into more details explaining what your understanding of the paper is? I'm reading it now but I'm not familiar with the field.

[noja]

For the cff page on Safari, create a bookmarklet to make it go pure full screen:

javascript:document.documentElement.webkitRequestFullScreen();

[mikewarot]

Holy cow.... that's really rough, you weren't kidding.

This is the closest I've ever felt to being a Borg.

[m463]

I think I must have turned off repetitive play in browser. wonder if there is an m4v version

[elric]

It's taken 12 years to get from "this stuff exists in mice" to "we now know it actually exists in humans and is not vestigial". That seems like a long time. People get brain MRIs with contrast all the time, is there any reason why this never showed up? Because no one was looking? Or because it's a slow mechanism?

[jhrmnn]

Looking up “brain MRI with contrast”, the biggest difference seems to be that in a regular MRI the contrast goes to the blood, but here it goes straight to the brain cerebrospinal fluid. You need open brain for that, so indeed doesn’t seem trivial.

[NeuroCoder]

Two things:

1. Blood brain barrier and CSF should be separate for all but tiny molecules. It's why CT angiograms are able to visualize distinct vessels. So it is pretty hard to directly interact with this sort of thing in vivo

2. A good chunk of the neuro community have been operating under the assumption that some of those mouse model findings are mechanisms in humans too. Since we couldn't easily prove it, people used a bunch of next best tools with fancy imaging that demonstrated it was very likely. On top of furter proof, this sort of study allows us to begin pinpointing exactly how close our next best tools are at estimating in vivo processes without opening up the head.

[rozab]

They injected a dye into the cerebrospinal fluid to confirm the pattern of diffusion into the brain.

I imagine this procedure would have to be confirmed safe in humans first. Also they needed subjects who already happened to be undergoing a specific type of brain surgery.

[physPop]

Its because we don’t normally inject Gad in CSF. Its kind of wild west to even do so, and these researchers were able to identify this unique dataset and ask some interesting questions.

[jb1991]

The main reason is because 12 years ago we didn't have ChatGPT to tell the researchers the answer.

[sharpshadow]

“Other studies have suggested that the glymphatic system may be most active during sleep.”

Not only that but also the right sleeping position is relevant here. I don’t recall the scientist but he studied primates and their natural sleeping position, exactly this position also opens up the channels for the cerebrospinal fluid to flush the accumulated brain waste.

[lazypenguin]

Do you recall which position?

[boringg]

Interesting - whats the frequency - response hypothesis? I don't think you would want to do lymphatic drainage everyday unless you had a problem with your system (?)

[canadiantim]

Really shows the slow slow slow glacial pace of science and how fragmented the information distribution mechanisms are…

[knodi]

Or the brain is high complex organ and full of MANY known and unknown functions which meet a specific or general need. Don't forget, it took us 100k years as human to get here, our current understanding of brain. you're being a little harsh here.