The Science Behind Dreams

Dreams are weird. It’s simply a fact of life that most of the time, the things that happen in the world of your mind during sleep are nothing short of odd. You could be flying, you could be chased by a horrific monster, you could be a dinosaur in a top hat, etc. It might seem like dreams are a bunch of random nonsense that the unconscious mind creates… but that wouldn’t be complicated enough, would it?  After all, this is the human brain that we’re talking about. While scientists are unsure exactly why we dream, it is agreed upon by just about all of them that what happens in your brain during dreaming  is crucial to your mind’s development. There are numerous theories created to explain dreams, but this essay will cover the main theory, which has to do with memory. 

The most commonly accepted explanation for dreaming is the idea that what happens in your brain during sleep, specifically REM sleep, has a lot to do with processing the day’s events, remembering important details while forgetting unimportant details, and associating the memories of the day with past memories (“Dreams…”). Before we get into the details of that, however, we have to understand the different stages of sleep. 

There are four stages of sleep: the first three are NREM, the fourth is REM. REM stands for rapid eye movement, and NREM means “non-REM”, or no rapid eye movement.  Basically, during REM sleep, everything is paralyzed except for the eyes, and certain organs. The body typically goes through this cycle 3-4 times a night, so once every 1-2 hours (Lockett). The most activity happens in the brain during REM sleep, and dreaming does as well.

Well, why is REM sleep important? As previously stated, there is very little knowledge on what happens to the brain while asleep. However, scientists discovered two things that happen in the brain during REM. First: the prefrontal cortex basically turns off during REM sleep (“Dreams…”). The prefrontal cortex is responsible for self-awareness, logic, and reasoning. This could explain why no matter how ridiculous a dream is, it always seems to make sense until you wake up. The second thing that researchers discovered is that during REM, the part of the brain that is in charge of memory (the hippocampus) and the part of the brain that is associated with fear and emotion (the amygdala) are extremely active, and the hippocampus is even more active compared to when someone is awake (“Michio Kaku…”). This supports the memory theory even more.

Thus far, we have learned that dreaming and REM sleep are heavily linked to memory, and processing the day’s events into your memory. But what does this have to do with the content of the dreams themselves? Like everything else in this field of study, nobody really knows, but there are a plethora of possible theories and explanations. Researchers have discovered that during NREM 3, which is considered deep sleep, the brain replays the day’s events very quickly, sometimes even backwards (“Dreams…”). However, during REM, which is when dreams occur, the brain replays the day’s events in normal time (“Dreams…”). This raises the question: why aren’t dreams just a replay of the day’s events? Obviously, there is no clear answer. The most plausible explanation, though, is that dreams are simply the mind trying to make sense out of everything happening in the mind. When the brain is processing the day’s events and memories, it is also associating those events with past experiences and memories. Also, as previously mentioned, the amygdala, the fear and emotion part of the brain, is more active during REM. All of this jumbled together could very well explain the random nature of dreams. It has also been shown that children, especially babies, spend more time in REM, most likely because they are learning much more about the world (“Dreams…”). After learning all of this, you’ll probably spend a bit more time in REM as well.

In conclusion, dreams are most likely the cause of your poor brain just trying to sort through the day’s memories. Your dreams are random probably because it’s a mix of your short-term and long-term memory, and they only make sense when you’re having them because your prefrontal cortex is off. While it’s true that there’s no clear explanation for dreaming, and probably won’t be one for a while, there’s one thing that’s obvious: dreams are very, very weird.