Why do we sleep? My latest suggestion is that NREM is glymph cleaning for mostly the cerebrum, our top brain. And during this sleep time, most cerebrum activities are reduced. And REM is glymph cleaning for mostly the brain stem, limbic system, and perhaps the cerebellum – the other parts of the brain. And during these sleep periods most of the activities connected to those parts of the brain are reduced or altered. Many facts seem to fit, and it can be tested to see if it is valid.
Muscle atonia during REM sleep.
Some suggest that we are paralyzed with muscle atonia in REM sleep to make sure we don’t act out our nightmares. I think it is just the opposite. Muscle atonia causes the nightmares.
REM sleep is one part of the nightly glymphatic cleanse of the brain (perhaps mostly the parts of the brain not including the cerebrtum). During that period the part of the brain that controls muscles seems to be ‘out for cleansing’ and that part of the body is paralyzed.
The nightmares may be just a reflection of that paralysis. The nightmares put into visual pictures the bodies shut down during REM sleep, of muscles due to the brain ‘closed’ for cleaning.:”
During this time body temperature approaches that of the environment. That may be because muscle atonia has stopped the muscles from producing body heat that comes from muscle movement -70% of body heat.