REM and Locked-In Syndrome:
REM (rapid eye movement-dream) sleep is similar to locked-in syndrome. How? Locked-in syndrome is rare fortunately, usually caused by a stroke, destroys part of the pons in the brainstem, and a person can’t move but they breathe and vertical eye movements are preserved. They are awake, thinking and imagining. More than one victim has written books communicating with their eyes. In REM dream sleep the brain can imagine, obviously, so the brain is active as if awake, but the dreamer is paralyzed but for eye movements and vital functions, which is known as sleep paralysis. There are all sorts of medical issues such as people with brief sleep paralysis some crumpling to the ground as in cataplexy, part of narcolepsy, and, while resting, unable to move at all, occasionally incorporating a brief dream-like vision. In fact, people subject to out of body experiences and Near Death Experiences where they get a glimpse of Heaven, are much more prone to sleep paralysis and narcoleptic symptoms, near proof their NDEs are dreams.
I thought that’s interesting, anyone else note the similarity between Locked in and REM? So I asked Chat GPT through Bing. It said no, there isn’t any comparison of Locked-in and REM except some people might dream while locked in. Really? I wrote, what about the fact that both cause complete paralysis but for breathing and eye movements, both implicate the pons? Thus responds Chat GPT, – OK yeah you are right. Other than that, REM and locked-have nothing in common, I can find. Something else I can help you with today?
But REM/dreaming is an altered state that implicates disconnections, deafferent, de-efferent plus dissociation with evaluative prefrontal cortex, an imaginative brain in a bottle. In REM sleep you are unable to move at all, yet your eyes move rapidly especially side to side, horizontally. Are you observing your dream, perhaps a tennis match? In Locked-in syndrome a portion of the pons in the brainstem is destroyed and one can’t move at all apart from vertical up and down eye movements. That’s because the midbrain, responsible for vertical eye movements, is still intact. REM is a state not a disorder in that REM utilizes the pons to achieve paralysis and generate horizontal eye movements. REM is readily reversible, locked-in not.
Dreams are largely achieved via disconnection. In REM you close out sensory stimuli, sight and sound conveyed to your cortex, via the thalamus. Certain ingoing and outgoing switches turn off. REM provides yet another disconnection, the critical evaluative prefrontal cortex. Pretty ridiculous nonsensical things are allowed as imagination is given free reign. So dreaming, we disconnect from incoming sensory stimuli. Dreaming finally frees us to truly figure things out, like a cabin in the woods. The dream state provides a perfect brain in a bottle thought experiment for the philosopher and an uploadable brain on a shelf of our science fiction future.
