Entering Fantasy Land: Why We Dream

You bound through the hot, greasy Amazon rainforest, trying to find that important thing. You hear rustling in the leaves and stand on guard. Out step your mother and father, looking lost.

“Hey! We were looking for you!” yells your mom.

Your dad points at your feet.

You look down and you are sinking into this purple-blue liquid, fast. One second, the liquid is to your ankles. Your mom and dad run to save you but by the time they run to you, it’s already to your thighs. You reach for your parents’ hands, trying to get a good grip, but the goo is too powerful. 

It’s already to your chest and your parents are trying to pull as hard as they can. 

Neck. Ears. You close your eyes.

You bolt up from your bed, breathing heavily. Noticing that you are on your bed, in the safety of your house, you relish in the idea that you are not drowning. You then think to yourself, why did I have that dream? What was the point? Why do we have dreams? You probably think about that dream for about five more minutes until the details start to slip away. Or maybe you forget about it altogether. Though much is unknown as to why we dream, what we do know is that rapid eye movement (REM) sleep, which is the stage where dreaming happens, is integral to our functioning and development.

REM Sleep 

There are five stages of sleep, the last and most important being rapid eye movement (REM) sleep. REM sleep is the foundational aspect of dreaming and having sufficient sleep [1]. During REM sleep, our brains work the same, if not more, as when we are awake [2]. Remember that Amazon rainforest in the beginning? In our dreams, as we move and explore the environment, it serves as practice for the brain [2]. However, the nerves that send signals to move our muscles are inactive (except the ones in the eyes), which prevents us from physically acting out our dreams [2]. It helps the brain respond to possible scenarios without actually putting the body through stress in those scenarios [2]. 

Further, REM sleep is very important for both memory and mental rehearsal, indicating that dreams may help us gain an understanding of what to do and how to act within our environment [2]. A study that used a positron emission tomography (PET) scan (an imaging test used to detect activity levels in the brain) showed that when we either imagine something or dream it, we activate our visual cortex [3]. Activating the visual cortex is one way that allows us to remember what things look like, informing our visual memory [4]. Visual cortex activation during a PET scan therefore suggests that REM sleep is important for visual memory formation and storage [5]. Memory is taken from the day, rehearsed and processed within our dreams, then stored in our long-term memory. The inability to have a normal REM sleep cycle can damage the creation and the demonstration of memories [6].

A study conducted with mice helped demonstrate how memory and REM sleep are linked [8]. A research group from McGill University used new technologies to silence GABA (gamma-Aminobutyric acid) cells, which are neurotransmitters that help with the functioning of the hippocampus [8]. The hippocampus is a part of the brain that contributes to the learning process and retains memories [7]. The GABA cells are the neurotransmitters responsible for inducing the feeling of tiredness and helping calm the brain. They silenced these cells in mice during their REM sleep cycle and found that when they were silenced, the memory-related activity decreased [8]. These cells are critical in humans for creating and retaining memories and the study shows that entering sleep does help memory-related activity increase.

REM sleep and the Regulation of Emotions

Dreaming also affects the development and regulation of our emotions [7]. Not getting proper sleep and initiating REM sleep can negatively affect the amygdala, a small part of the brain that helps process strong emotions, namely fear [9]. When sleep-deprived, the amygdala is more sensitive to negative emotions [10]. The amygdala is also active during REM sleep [11] and moments from a person’s waking life are replayed as dreams. This is especially robust with highly emotional memories, as seen in people with post-traumatic stress disorder (PTSD) [9]. PTSD patients are people who undergo traumatic events and are unable to get rid of traumatic memories or their fear responses to them. Common fear responses include an increased heart rate, shortness of breath, and sweating [12]. PTSD patients who received fear extinction training (a practice to eliminate certain fear responses) report having regularly vivid traumatic events displayed as dreams [13]. Fear extinction training gives individuals different types of therapy to learn how to not fear triggering situations. It is a type of psychological  classical conditioning where the patients are exposed to different types of conditioned stimuli [14]. The hope is that after the process, the fear responses will vanish. However, the interruption of their REM sleep disrupted their fear extinction progress and made it so that they still had some of their fear responses [15].

Dreaming Phenomena during REM sleep

As stated before, there are many different types of dreaming other than the standard REM sleep. For instance, lucid dreaming involves an individual being aware and having control of their dreams and its events [16]. There is some debate about the causes of lucid dreaming. Data from a study performed by researchers in the department of psychiatry from both Harvard and Yale University suggested that lucid dreamers performed better on the Iowa Gambling tasks (a task that simulates real-world decision making) that engaged the ventromedial prefrontal cortex function [17], which is responsible for decision making. Another theory for lucid dreaming is that it stems from a difference in personality traits. The specific trait is known as having “thin boundaries.” People with thin boundaries often confuse reality and fantasy in both waking and dreaming states [18]. Having these thin boundaries can also be helpful for people that suffer from nightmares since they can control the content of their dreams. These thin boundaries theory would allow for the person to be able to have a sense of reality within their dreaming states, hence lucidity [18]. 

Conclusion and Limitations

Entering REM sleep and the sleep cycle altogether are very integral to our well-being, but we often overlook it and take that process for granted. We often prioritize and pull all-nighters to get our work done. Although sleeping and dreaming are very important, they are under-researched topics. Many of the more recent articles from the past five years reference papers from the 1990s to support their research. The EEG was invented in 1929, so we have only had the technology to record and understand brain waves for less than one hundred years [19]. We need better advancements to our current technology to understand our brain at an in-depth level. Perhaps, advanced technology can be used to better verify earlier sleep studies. This way, we can not only learn more about the brain but also find better ways to study the memory-dreaming link and the regulation of our emotions. Are we able to manipulate our dreams to our benefit? With the help of research, we could answer this and many other questions about our health and how it might be related to how we sleep or dream. Because there is a lack of new technology, new research, and because dreams are mostly self-reported, it is extremely difficult to get accurate research on dreams. It would be useful to learn more about sleep or dreaming because it is beneficial and foundational to our health. The more we can learn about it with modern technology, the more we can learn about how we can help ourselves lead healthier lives.

References:

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