Dreams are like individual movie experiences that play in our thoughts as we sleep, combining bits and parts of our lives to form bizarre and interesting storylines. Sometimes these dream scenarios use actual recollections from our past experiences, such as activities we’ve done or places we’ve been.
Sometimes dreams involve things that never happened, but our minds make them seem genuine. When we dream, these made-up experiences, known as false memories, might appear to be equally valid as the real ones. The big question is why. Why do our brains form memories of events that have never happened before?

The Memory Mix-up
The hippocampus is a part of your brain that aids memory, such as what you studied in class or did with your friends. REM sleep, or Rapid Eye Movement sleep, occurs when your eyes move swiftly beneath your eyelids, and this is when you get the most vivid dreams.
During REM sleep, your brain organizes everything you did that day. The hippocampus processes your memories while you are in REM sleep. It stores the things you did and learned in your long-term memory. It sometimes combines disparate recollections, such as something from last week and something from years ago.
Because the hippocampus is attempting to make sense of diverse memories, it might occasionally confuse things. Since your brain is merging multiple memories, you may dream about things or places you’ve never been before. The hippocampus also incorporates current experiences and emotions into your dreams, so if you had an exciting day or felt strong feelings, these may manifest in your dreams as well.
Note: Studying before bedtime can help you recall things better since the hippocampus helps you store information in your long-term memory.
Imagination Takes the Stage
In dreams, your unconscious mind frequently brings up things you secretly want, are afraid of, or haven’t solved yet. Sometimes you dream about receiving what you really want. This is known as a wish-fulfillment dream. For example, if you truly desire to go to an amazing destination, like Bali or the Maldives, you may fantasize about being there. These dreams reflect your deepest wants and desires.
In this case, déjà vu also plays a role. Déjà vu is the strange sensation of having done something previously, even if you are aware that you have not. It’s as if your mind is tricking you into believing something is familiar. When you dream, your brain creates stories out of fragments of reality and imagination. You may experience déjà vu later on if anything in real life fits what you dreamt about. It’s as if your brain knows something about your dream and believes you’ve seen it previously.
Conclusion
False memories can occur in dreams because our brain merges true memories with imagination while we sleep. During sleep, the hippocampus, which aids memory, works hard to organize and at times confuses memories. It also incorporates recent events and feelings into our dreams, creating a hybrid of reality and fantasy. This combination can reveal our deepest aspirations, worries, and unresolved problems. When real-life occurrences remind us of our dreams, this process might trigger déjà vu.