While a normal human like you is sleeping the night away, your body transitions through a series of sleep phases. The final phase, REM sleep, is the stage that usually contains vivid dreams. During these dreams the brain acts as if it were awake, and even sends out messages to the body in the same way. Despite this surge of activity, the body remains in it’s sleeping state, not heeding the instructions of the brain. This is possible thanks to the inhibition of motor neurons in the spinal cord, essentially blocking the brain’s signals from reaching the body.
During a cataplexy episode, a misfire in the brain causes those same motor neurons to be blocked. The brain is still fully awake, receiving and processing data from the senses, but it has no way to send messages to the body. As a result, the muscles go limp, the same way they do in REM sleep.
If all of this talk about motor neurons and sleep stages has you confused, just think of cataplexy as the opposite of sleepwalking: instead of moving around while you’re asleep, you can’t move while you’re awake.
Speaking of sleep, have you ever heard of polyphasic sleep? It’s an amazing body hack that allows you to go for days at a time on as little as two hours of sleep. Dustin Curtis wrote a great article on the subject. You should also take a tour of his brain – a quick overview of the different areas and functions of our grey matter, along with some actual MRI images. Once again, thanks for reading!