Scientifically, what is going on in your brain during hypnotic regression?

I have heard it used as a method to access lost memories from your subconscious, particularly:
>recalling traumatic memories from the past
>recalling alien abductions in which your memory was wiped
>recalling your past lives

I am too much of a pussy to try it myself. Many people take these experiences to be truthful, but it seems that this hypnosis could just be a method of inducing false memories or even dreams during the waking state. Is anybody familiar with hypnotic regression?

(For fun, here’s the Leddit approved hypnotic regression YouTube video for viewing your past lives)
https://www.youtube.com/watch?v=pKM2i3pi5b8