Can Dreaming Clean Up Your Brain?
A study (in mice) suggests that capillary blood flow in the brain increases during REM sleep, which removes waste products
What dreams may come
When we lay ourselves to sleep, our brains and the rest of our bodies go through a set of sleep cycles.
In humans, each cycle tends to last between 70 and 110 minutes, with those earlier in the night on the shorter side, and the later ones a bit longer. (In infants the cycles are about 50–60 minutes.)
Each cycle has four stages: non-REM1, non-REM2, non-REM3 (aka slow-wave sleep), and REM.
(Imaginative naming there…)
Especially this last stage, REM or rapid eye movement, captures our attention. It is the final part of a sleep cycle, lasts about 10 minutes in the first cycle, and gets progressively longer in the following cycles.
REM is also a physiologically weird stage. Our brain starts to squirt large amounts of the neurotransmitter acetylcholine and holds back on the release of histamine, serotonin, and norepinephrine. The brain…
