>The team discovered that this increased flow was possible in part because when mice went to sleep, their brain cells actually shrank, making it easier for fluid to circulate.

It could be that the brain needs to fire up for short periods in order to help pump the increased fluid out to prepare for another rinse.

What I thought of, when I read that was that perhaps the shrinking is related to reduced blood flow or reduced blood absorption (does blood pressure raise or lower during sleep?) and this is also related to sleep itself, in the same way that a chokehold causes unconsciousness by restricting the oxygen reaching the brain

Hmm... Interesting, almost like a heart. Expand, contract, expand, contract. That could be why we have multiple dreams a night.

I read somewhere in the last 10 years that dreams were practice for real life situations. After hearing that, when I awake in the middle of a dream, I always test that hypothesis, and sure enough, sometimes is quite plausible.

Most of my dreams involve a lot of supernatural events and scenarios that'd be quite unlikely in real life. Am I preparing for a day soon where magic, superpowers and other super natural events become real?

Perhaps if you where out hunting & gathering instead of watching movies, reading books and playing videogames your dreams would be more "real".

bkkssnn hit the nail on the head, but I'll leave this here:

https://www.psychologytoday.com/blog/the-literary-mind/20091...

as a reply to your snarkiness.

Perhaps you missed the "sometimes"...

This reminds me of how they used GTA V to train driverless cars.

If dreams only were the result of some cleanup process (i.e. just arbitrary neurons firing), I imagine they would be a lot less coherent and all events would be (stochastically) independent. While dreams usually don't much make a huge lot of sense, they are sometimes quite realistic and "past" events seem to influence "later" events.