> Lewis and colleagues showed that CSF flow during sleep follows a rhythmic pattern in and out of the brain
> Most significantly, they found a flux of CSF out of the brain just as those lapses occurred. After each lapse, CSF flowed back into the brain.
I can't believe the authors of the article didn't address one of the most obvious questions: Where does the CSF flow to and where does it flow back from? It's not like there are pipes leading out of the brain, or the CSF will just leave my brain through my ears or anything, will it?¹ What happens with the waste products? (¹ Though it would be kinda funny if this was where snot comes from.)
EDIT: Wikipedia's got the answer:
> Clearing waste: CSF allows for the removal of waste products from the brain,[3] and is critical in the brain's lymphatic system, called the glymphatic system. Metabolic waste products diffuse rapidly into CSF and are removed into the bloodstream as CSF is absorbed. When this goes awry, CSF can become toxic […]