Why can't we remember our dreams?

There are several theories as to why we often cannot remember our dreams. One has to do with the hippocampus, which is part of the brain vital for transferring memories from short-term to long-term storage. During sleep, the brain’s regions turn off at different times, and one of the last to turn off is the hippocampus. If the hippocampus is the last to go to sleep, it may also be the last to wake up. According to Thomas Andrillon, a neuroscientist at Monash University, “You could have this window where you wake up with a dream in your short-term memory, but since the hippocampus is not fully awake yet, your brain is not able to keep that memory.”