You’re walking on a garden path on a bright summer day. The day is warm but the air is cool, and you feel more relaxed than you have in a while. You hear a low buzzing noise behind you and you turn around to see a single bee. You’re wary, but otherwise leave the insect alone. But then that bee becomes two bees. Then three. Then five. Then ten. Then fifty. Then there are suddenly more bees than you can count and you’re freaking out because OHMYGOD THESE BEES ARE GOING TOWARDS YOU STINGER FIRST AND… you wake up.
Okay, so maybe this isn’t what your typical dream-turned-nightmare looks like, but it probably is to someone who’s allergic to bees. Question is, why do dreams and nightmares exist at all?
The truth is that we don’t know exactly why these occur (yet; I’m sure they’ll figure it out in the future). Scientists and philosophers have an ongoing debate as to why we create these stories while we sleep, but the most widely known and accepted is Sigmund Freud’s theory which says that we dream so that we can sort through repressed longings.
But even if we don’t know the “Why?” to dreaming, we do know how it works. People used to think that when we fell asleep, our brains would also shut off and lay dormant. But we know now that our brains are just as active when we’re asleep as when we are awake – it’s just that the activity is happening in different parts.
When we’re awake, majority of the parts of our brain are working in tandem – the parts that control our sensory perception, language, fine motor control, involuntary actions and comprehension all work depending on the situation presented. But when we go to sleep, the other parts of the brain – the ones involving speaking and fine motor control, for example – aren’t as active and in a sense, “shut off”. But the brain functions in other parts are still as active, if not more so when we sleep. Dreaming is proof of that.
Dreaming occurs in the last stage of sleep called the Rapid Eye Movement or REM stage. During REM sleep, our breathing becomes quicker and shallower, and our eyes move rapidly in different directions (hence the name). Our limbs, however, are temporarily paralyzed to stop us from acting out what we do in our dreams.
REM sleep starts with signals coming from the pons, an area at the base of the brain. Those signals move to the thalamus, which delivers the signals to the cerebral cortex for “processing”. The pons is also the one in charge of sending signals to shut off the neurons in the spinal cord to paralyze our limbs.
So that explains how the brain works when we dream, but what about when we have nightmares? Is it really just “a bad dream”? Studies have shown that a nightmare is not just a bad dream – a part of the brain called the amygdala is very active when you’re having a nightmare. The amygdala’s function includes processing and handling emotional reactions, such as fear or anger. So it makes sense that the possible over-stimulation of this part during REM sleep could lead to the fear we experience.
But what leads to the amygdala being over-activated? Well, one reason could be that you’re worried or conflicted about something. If you think about a problem for the whole day, chances are it will carry over while you sleep. Another reason is poor eating habits – having a snack before bed could lead to more nightmares. Eating in the late hours of the night could lead to higher brain activity and brain metabolism. Trauma is another factor that can influence the frequency of nightmares – experiencing intense feelings of fear, anger or embarrassment leaves a mark on the brain and how it thinks.
Okay, okay. So we know how the brain works while we’re asleep, how nightmares are different from dreams, and where nightmares could come form, but what about remembering our dreams? How come we remember some dreams and forget others as soon as we wake up?
Emotionally intense dreams were found to have a connection with the amygdala and the hippocampus. The hippocampus works to move information from short-term to long-term memory, so intense dreams are stored in our long-term memory after we have them.
So whether or not you believe that dreams are emotionally significant, you have to admit it’s pretty amazing they exist. There’s so much brainpower that’s used, and we’re unconscious when we’re using it. Imagine what could happen if we could control that brainpower in our sleep (but, lucid dreaming is another topic altogether). Sweet dreams, everyone!
Sources:
(1) Van Der Linden, Sander. "The Science Behind Dreaming." Scientific American Global RSS. N.p., 26 July 2011. Web. 19 Sept. 2015.
(2) "Brain Basics: Understanding Sleep." : National Institute of Neurological Disorders and Stroke (NINDS). National Institute of Health, 25 July 2014. Web. 19 Sept. 2015.
(3) Borreli, Lizette. "The Dark Science Behind Your Nightmares." Medical Daily. N.p., 31 Mar. 2015. Web. 19 Sept. 2015.
Article by Rio
Art by Sean
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Rio is (trying to be) an engineer-in-training, an athlete and a singer, with her love for science, sports, and music in that order. She's also (trying to be) a writer, with her trusty laptop/phone, sour cream flavored chips and/or strawberry ice cream. (Whether or not she succeeds is another story altogether).
Sean is a 15-year-old muggle-born who is proud to say that he is perfectly abnormal, thank you very much. Peculiar in many ways, he is a far cry from that common stereotyped teenager. He has a great passion for art, and would love to do nothing more than making collages and other creative thingamajigs.
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