Every night, when you go to sleep, you dream. You might not remember exactly what you dreamed — or you may remember every detail with complete clarity, even if it didn’t make any sense — but even if you are certain that you didn’t dream, you likely did.
Although dreams are fascinating, and psychologists and scientists have devoted years to uncovering the meaning and purpose behind dreams, the fact remains that no one really knows why we dream. One of the most widely accepted theories is that dreams help the brain process memories, categorizing what is important and what isn’t. Others suggest that dreams are a way of making sense of emotions. Although we may not have answers about the way of dreaming, we know quite a bit about what’s happening with the brain while we dream. While you are dreaming about showing up to math class in your underwear, your entire brain is active — and many of the things that are happening would be alarming if they happened while you were awake.
Dreaming and the Different Parts of the Brain
Maybe it’s happened in one of your relationships: One morning, a partner wakes up and is angry at the other for something they did in a dream. Even though the dreamer logically understands that their partner is innocent of the perceived slight, the emotions from the dream remain, whether anger, sadness, or something else entirely.
If this has ever happened to you, you can thank the limbic system in your brain. The limbic system — located in the center of your brain — is responsible for your emotions both during sleep and wake periods. When you have an emotion in your dream, such as anger with a partner for doing something terrible, it’s triggered by the limbic system. However, the part of the limbic system that’s most active during sleep is the amygdala, which is most commonly associated with fear, aggression, and unpleasant emotions. The amygdala is why we experience nightmares. Interestingly, brain scans indicate the amygdala tends to be most active during REM sleep, especially toward the early morning hours. Scientists suspect there is something biological happening during REM sleep that triggers this activity, but otherwise, there’s no clear explanation.
Activity in the limbic system is only one part of what happens in the brain while dreaming. The visual cortex, at the back of the brain, is also highly active during dreams. Humans are by nature visual creatures, so it only makes sense that the part of the brain that processes what we see is one of the most active parts during dreams. Visual cortex activity is connected to what we’re seeing in our dreams, from the people we encounter (hello, George Clooney!) to the places we visit (the job we hated) to the experiences we have (so this is what flying feels like.)
However, there is one part of your brain that isn’t working while you are dreaming, and that’s the frontal lobe. The frontal lobe is where logic and reasoning take place; it’s where we make sense of all the chaos happening around us. Yet in dreamland, we just accept what’s happening, no matter how fantastical or nonsensical. One sleep expert likens dreaming to psychosis, as during dreams we hallucinate and lose touch with reality, having wildly swinging emotions. We become disoriented, without any sense of time or place. And then, when we wake up, much of what happened is instantly forgotten. All of this is largely because the frontal lobe has all but checked out for the evening, letting the rest of the brain take over.
Why Dreaming Matters
So even with this understanding of what’s physically happening in the brain when we dream, it still doesn’t explain the why. Research with patients suffering from PTSD points to dreams being important for emotional integration of memories; that is, they help the brain process memories and understand the associated emotions and integrate them into your long term memory. Because nightmares are so common among those with PTSD or who have suffered trauma, the assumption is that some memories are just too intense to be easily integrated, triggering the fear response.
However, some research suggests that dreams do more than just help manage memories. Some psychologists believe that dreams actually provide a form of therapy, allowing people to process their experiences, without emotional interference. Still others believe that dreaming is key to creativity, as it allows your brain to connect experiences and information in new ways that you might not otherwise think of. This could explain why we often wake up with new solutions to problems, and the things that seem overwhelming at bedtime seem less so in the morning.
Whatever the purpose of dreams, it’s clear they are a natural and important part of our overall mental and emotional health. Even if you think that you don’t dream, you do. And when you have those dreams where you wake up angry? Just remember it was only a dream.
