You don’t form longterm memories while asleep; you lose the last few minutes before you drop off, as well. Short-term memories are held, but they don’t get stored.

And the same applies while you’re dreaming - nothing’s getting recorded. You can pull it out of short-term right after you wake up, but that fades right out.

When you do remember dreams, it’s because you remember remembering them while you were awake. If it was vivid enough to go over hard enough, then the second-hand memory gets stored.

We forget much of it but its still in our head somewhere. Theres been so many times a dream reminds me about another dream and act as a sequel of sorts. Days to years back. How much storage do we really have up here?

Could be that dreams arent stored at all, that if dreams are just random neurons following random-ish paths then they occasionally they hit the same pathway again and replay stuff, maybe?

In my case, it is more like 5-20 seconds, not 5 minutes. Do you really remember dreams that long? They raid very rapidly, and I usually remember only those parts that I have repeated myself (thought about) right after waking up.

Interestingly, sometimes I revisit fictional places/topics in the dream, which otherwise I forgot. And upon waking up I am like, “yes, I dreamed about it before”, but I would not remember about it otherwise.

Short term memory vs long term memory.

That’s why some people keep dream journals by their bed, because if you do something with that information right away once awake, you’ll probably commit it to long-term memory.

This is a somewhat personal theory, not something I know science to confirm, but I imagine, we evolved to have dreams, because they help us play out situations that might come up similarly in the future.

So, maybe you won’t ever actually be in underpants in school, but you might still get into an embarassing situation and then know how to laugh it off.

So, the learnings from those dreams, those have to be remember. But the ‘simulated’ situations in those dreams, they would be bad to remember, because they never actually happened. So, it’s also advantageous for survival to not remember them, which is why we generally evolved to not do so.

As with most brain questions, nobody knows exactly.

One theory for the purpose of it, is to prevent us from confusing things we dreamed about with things that actually happened.

I’ve heard it said that the brain doesn’t distinguish between a real event and an imagined one. Now before you poise your digits with acerbic comebacks, allow yourself a second to think that over.

When you dream, it’s a form of reality for your brain. It believes what is unfolding is actually happening, your pulse may quicken, your heart rate can increase, you can even have a kind of discharge from your male parts if it is realistic enough.

Of course all sweeping generalizations have exceptions and I’m not saying I don’t see how the brain makes clear distinctions between dreams and waking states. What I’m saying is, BOTH dreaming and waking experiences are all parts of what we call “reality.” The dream state is real enough to make our body react according to what is going on our heads.

Just something to think about. The above statement was read to me by a piano teacher who was endeavoring to show me how imagination can make something reality, how thinking about the mood of a piece could make me a better piano player by utiliziing internal imagery.

Dreams don’t really make any sense. When you wake up, you’re remembering the emotions and linking them with images, but as the feelings fade, unless you were actively making them into a narrative, the random stimulus soup doesn’t have any staying power worth remembering. Trying to remember just corrupts your working memory and will make you change and add details that weren’t there. Same reason eye witness testimony is very often wrong.