Sleep ≠ Total Shut Down

There is a lot going on when you go to sleep. Previously, I simply thought that you are either awake or you are asleep. I thought if you are awake, you are involved and aware of things, but if you are asleep, your brain is basically shut down.

            My simplicity of thinking was flawed. There are so many stages of sleep, and so many processes going on while you are asleep and unaware of their occurrence.

            Stage 1 of sleep is not even truly sleep. It is the stage where one dozes and has hypnagogic sensations. A hypnagogic sensation is where your body creates a sensation without any light or stimulus. Personally, my hypnogogic sensations in school are pretty intense. I often doze into stage 1 without even knowing it, and then my head will suddenly jolt forward without any stimulation.

            Stage 2 of sleep is legitimate sleep. The brain waves are a bit increased in amplitude, but it is still not deep sleep. A person in stage 2 of sleep is still pretty easily woken.

            Stage 3 and 4 of sleep are similar to each other. This is where you are really out of it. Your brain waves contain delta waves, which are long, deep, relaxed brain waves causing a deep, relaxed state of sleep. The main difference between stages 3 and 4 is longer delta waves in stage 4. In any case, it would take a lot more pokes on the shoulder to wake someone in stage 3 or 4 than someone sleeping lightly in stage 2. 

            And then, after cycling thru the stages and making it back to stage 2, you enter REM (Random Eye Movement) sleep. Your brain waves are similar to those when you are awake. Isn’t that weird? You are not awake, but your brain waves are moving like they are awake. You might even call it a paradox. And that is why it is called paradoxical sleep! You brainstem blocks these REM sleep brain waves from reaching your body; otherwise, you would be all over the walls. This brain stimulation leads to dreams, and your REM sleep periods get progressively longer as you sleep longer.

            So I was very flawed in my previous thought. Your neural activity does not by any means just shut down while you sleep. It is still churning out brain waves. Your brain is always busy.