Eine neue EEG- und fMRT-Studie zeigt, dass Aufmerksamkeitsschwächen, die bei Menschen mit Schlafmangel zu einem Abschalten führen, mit einer Welle von Liquor cerebrospinalis aus dem Gehirn einhergehen. Solche Wellen treten normalerweise im Tiefschlaf auf und sollen dem Gehirn dabei helfen, Stoffwechselabfälle auszuspülen, die sich tagsüber ansammeln.

I’ve linked to the news release in the post above. In this comment, for those interested, here’s the link to the peer reviewed journal article:

https://www.nature.com/articles/s41593-025-02098-8

From the linked article:

Scans shed light on changes in brain when we zone out while tired

Study finds **lapses of attention in sleep-deprived people coincide with wave of fluid flowing out of the brain**

It’s never a great look. The morning meeting is in full swing but thanks to a late night out your brain switches off at the precise moment a question comes your way.

Such momentary lapses in attention are a common problem for the sleep deprived, but what happens in the brain in these spells of mental shutdown has proved hard to pin down.

Now scientists have shed light on the process and found there is more to zoning out than meets the eye. The brief loss of focus coincides with a wave of fluid flowing out of the brain, which returns once attention recovers.

The lapses in attention came with striking changes. Scans revealed a **wave of cerebrospinal fluid being expelled from the brain moments after attention dropped and returning a second or so after the lapse ended. Such waves are normally seen in deep sleep and are thought to help the brain flush out metabolic waste that builds up during the day.**

Other measurements showed that the pupils of people’s eyes constricted about 12 seconds before the fluid left the brain and returned to normal after the lapse. Breathing and heart rate also fell, the researchers report in Nature Neuroscience.

While more questions remain, **the lapses seem to happen when the brain tries to juggle normal cognitive functioning with essential maintenance that is normally carried out during sleep**. “It’s your brain trying to take a break,” Yang said.

I wonder if the constant „daydreaming“/zoning out from ADHD is actually the brain cleaning it self more regularly, due to hyperstimulation byproducts.

Does anyone ever get this when driving? I sometimes zone out on stretches of road that I know well and then I will suddenly be back in the room aware that I have gone a distance with very little conscious presence. Autopilot of a kind! It isn’t related to sleep as often happens when I am well rested.

Very interesting. As someone diagnosed with IIH (Idiopathic Intracranial Hypertension), I have noticed that sleep deprivation coincides with less headaches and neurological symptoms. Having tracked my sleep several times over the years, I have also noticed I am almost never getting appropriate amount of deep sleep. Often non at all. Raised intracranial pressure also causes ihers to suffer with insomnia, or fragmented sleep when icp is particularly high. It would be interesting to see a study spring board from this one concerning ICP and Ih.