system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens in the brain when you drink so much alcohol you can’t remember what you did?

I recently turned 21, and I drank so much (in a safe environment with my husband, no driving or drugs or anything like that) that I mentally “blacked out”, but during the course of like 6 hours I was still active and doing ridiculous things - all of which are now documented on video. What causes that? I remember very small bits and pieces but mostly it’s just blank. Nothing. Sorry if this is a dumb question or has already been asked and explained, it’s just been on my mind recently. Thank you!
gpt
So there is a part of your brain called the hippocampus. This plays a huge part in the creation, care, and feeding of memory. Alcohol slows down how your nerves communicate in that part of the brain. This basically interferes with your brains ability to transition short term memories to long term memories.

That's why you can't recall. Your brain wasn't able to form the memory.