Why Do We Dream?

 by Eliza Stevens

Dreams are hallucinations that occur during certain stages of sleep. Dreams are usually their strongest during REM sleep, also known as the rapid eye movement stage. During REM we will experience our most vivid dreams. This is explained by the significant increase in brain activity during this period. REM is characterized by small, variable-speed brain waves, rapid eye movements, increased heart rate and muscle paralysis. It is an essential part of our sleep cycle as it is imperative for our learning, making and retaining memories. Scientists know a lot about the role of sleep, it regulates our metabolism, blood pressure, brain function and many other aspects of our health, but explaining the role of dreams is much more challenging.

When you are awake you will notice that your thoughts have a certain logic to them, you might be thinking about plans for the weekend or what you are going to have for dinner, but when you are asleep and dreaming they often make little or no sense at all. This may be because the emotional centres of the brain trigger dreams, rather than the logical regions. Three brain structures appear most closely linked with emotions: the amygdala, the insula or insular cortex, and a structure in the midbrain called the periaqueductal grey. A paired, almond-shaped structure deep within the brain, the amygdala integrates emotions, emotional behaviour, and motivation. Dreams are usually personal thoughts based on the activities that you have done recently, this could be a conversation you have had or an issue in your life, or a book you have read.

Some theories involving the purpose of dreams include the idea of dreams as therapists. This means that dreams may be a way of confronting personal emotional dramas in life and because when we are asleep we experience our brain operating at a much more emotional level than when we are awake, it is possible to find yourself having an emotional thought regarding your feelings that you wouldn’t have when you are conscious. 

Secondly, as our amygdala is the part of our brain that is most associated with fight or flight and our survival instincts, one theory suggests that our brain is preparing us to get ready for a threat. However, as I mentioned earlier the brainstem sends out a nerve signal during REM to relax our muscles and this is when we experience muscle paralysis, therefore, as a result, we don’t try to punch or run in our sleep. 

A further theory is that dreams play a significant role in storing our important memories and things that we have learned. Our dreams also help get rid of unimportant memories as they sort through complicated thoughts and feelings, it is a stage of memory cleansing. Research has shown that sleep helps us store memories, for example, if you learn new information and go to sleep not long after, you will be able to recall it better than if you were asked to recall that information without the benefit of sleep. This is why before big exams, or after doing a lot of revision for tests you should make sure that as much as you are giving time to work you are also prioritizing your sleep as it will ensure that you are able to remember the information you were revising. Therefore sleep is a crucial part of success in exams and recalling information to the best of our ability.

The question of why do we have nightmares, however, is another question. As we already know dreams help us deal with emotions and memories, having a nightmare is considered a dream that is frightening or upsetting. These tend to be caused by stress and anxiety. They are further caused by how much or how little sleep you have had. If you have had one or two days of sleep deprivation you are likely to have much more vivid dreams as your brain will be more active in the REM stage. Furthermore, hormones are an impacting factor on the production of our thoughts and emotions and this leads to intense dreaming. For example, when you are pregnant you are likely to experience much more acute dreams as your production of hormones will be greater.

Therefore, in order to have better dreams and a finer performance in exams after copious amounts of revision and recall, make sure you get at least 8 hours of sleep to help your brain store your memories. Furthermore, if you want to make sure you don’t get nightmares, sleep frequently and try to determine a sleep routine in order to not disturb your sleep patterns and cause your brain activity to increase during the stage of REM.