system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is happening in my brain when I "zone out" and I am quite literally thinking of nothing?
gpt
Your brain is actually working normally and you probably thought of many things, but due to not being focused on anything you immediately forgot as soon as your mind stopped wandering.  
  
Happens a lot if you're really tired, and have micro sleep.
  
That being said, studies have shown a modified brain activity during meditation or hypnosis, no idea if this is comparable.