It was when I was at boarding school that I first learned that I can be woken up in the middle of a dead sleep and appear to be fully awake and have a conversation, but once I’ve gone back to sleep I forget about the experience entirely. My roommate would refer to conversations we’d had in the middle of the night and I had no idea what she was talking about.
I used to think of this as me sleep-talking, but now I think it’s more like this: The part of my brain responsible for making and storing memories remains asleep. Even though I am functionally awake, my brain is not capable of storing the experience. For me, it’s like it never happened. It always gave me a creepy feeling to know that this other self I don’t know about was awake in the world doing and saying stuff when “I” was not. Despite the fact that for all outward appearances this alternate self does not behave in an unusual manner. She is still me, I just don’t remember her experiences.
It’s a small glitch in my brain system. Overall, my noggin’ works pretty well and I can rely on it to give me better-than-average recall of events and facts. My partner’s workplace will fight to get me on their team for the annual quiz night at the office. I’m pretty good at Trivial Pursuit and Jeopardy.
But there for the grace of my neurologically normative brain go I. Brains can play tricks on us. We have to trust them 100% yet they are not always trustworthy. It does give me a creepy feeling to think about this.