We spend a third of our lives asleep. While we are sleeping, we dream. Many people don’t remember their dreams. Those who do wake up, and they only remember the details of their dreams for a short time. Soon, the memories begin to fade, and you fall back to sleep. If you were awake and you forgot most of your day, it would have you worried, and you would be rushing to the doctor. Forgetting our dreams is normal, and it makes you wonder why. Why can’t we remember our dreams?
Thomas Andrillion is a neuroscientist at Monash University in Melbourne, Australia. He says that we have a tendency to forget our dreams immediately. Those who say that they never dream likely just forget them easier than those who remember them. Thomas believes that people who claim to have never remembered a dream in their entire life might recall them if they are awakened and asked the second they wake up. While the exact reason that some people cannot remember their dreams in unknown, scientists have gained some insight into the memory process during sleep.
What Happens When You Sleep?
When you fall asleep, not all of the regions of your brain go offline all at the same time. According to a study published in the Journal Neuron in 2011, the last region to go to sleep is the hippocampus, which is a curved structure that sits inside each hemisphere in the brain. It is this part of the brain that is responsible for moving critical information from your short-term memory to your long-term memory.
Last To Go To Sleep
Thomas believes that if your hippocampus is the last area of the brain to go to sleep, it could be the last to wake up. This means that you have a window of time where your dream is stored in your short-term memory, but if your hippocampus is not fully awake, it cannot be saved as a long-term memory. Thomas says that this could be the reason why dream memories can be so fleeting. He says that this doesn’t mean that the hippocampus is inactive through the night. Actually, this part of the brain is very active when you are sleeping, and it is storing the memories of your dreams. It just doesn’t stay awake long enough to download them to your long-term memory.
There is data that has shown that during some stages of sleep, your hippocampus is awake and sending the information to your cortex, but it isn’t receiving any new information. This type of communication is considered unidirectional, and it allows your memories to be sent from the hippocampus to the cortex for long-term storage, but the hippocampus can not register the new information.
When you wake up, your brain needs about two minutes to get its memory encoding abilities back on track. Before these two minutes are up, memories cannot be made because these essential memory-making areas of the brain are not awake, even though the rest is up and going.
In 2017, a study was published in the Journal Frontiers in Human Neuroscience. During the study, researchers in France monitored the sleep patterns of 18 people who report remembering their dreams almost all day. They also had 18 other people in the study who say that they practically never remember their dreams. The researchers discovered that those who couldn’t remember their dreams woke up less often during the night, and those who could remember their dreams woke up more often. Those who woke up frequently during the night were awake for an average of two minutes, and those who didn’t remember their dreams remained awake for about one minute.
Experts believe that our poor ability to create memories when we are sleeping could be liked to the changes in the levels of our two neurotransmitters, acetylcholine, and noradrenaline, which are essential in memory retention. When we fall asleep, the levels drop drastically. When we are in REM sleep, which is we have our most vivid dreams, the acetylcholine returns to the wakeful levels, but the noradrenaline remains very low.
Dreams That Just Aren’t Memorable
According to Earnest Hartmann, a professor of psychiatry at Tufts University School in Medicine, the reason that we don’t remember are dreams could just be that they aren’t memorable enough. Mundane dreams may not be significant enough for the brain to remember. If you have a dream that is emotional or important in your waking life, you have a better chance of remembering them.
With all of these studies about dreams, we still don’t know a lot about them, and how our brain uses the information and stores it. There are many mysteries about sleep and dreaming that we may never find the answers to.