system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What exactly is Déjà vu and what neurological events are happening to make it occur?

I have always found Déjà vu to be very interesting so I wanted to find your guys input on the subject.
gpt
Nobody knows for sure, is the short answer.

The slightly longer but still short answer is that the *best guess* anyone has is that it's a temporary "short circuit," of a sort, involving your long-term and short-term memory. Your knowledge of things that happened to you two seconds ago comes out of your short-term memory, obviously. But the guess neuroscientists have is that it's possible for something to go wrong, probably in your hippocampus, that gives you the *sensation* of drawing on your long-term memory instead. So something that happened to you two seconds ago "feels like" it happened to you days ago, or longer.

But again, nobody knows for sure. It's a difficult phenomenon to study, for obvious reasons.