You might recall some of the good and bad dreams you’ve had throughout your life, but you might not know why you had those dreams, what they meant to you, and why you can recall only a few of all the dreams you’ve ever had in your life. Multiple neuroscientific theories have been proposed to resolve the mystery of dreams. Read on to know about what science knows, and what doesn’t, about the dreams we experience during our sleep.
Sigmund Freud and Carl Jung (his student) proposed in his Theory of Dreams that dreams might help us resolve and sort through our long-awaited, unfulfilled, and repressed wishes.
Some neuroscientists also propose in “synthesis-activation theory” that dreams have no meaning as such, but happen due to randomly intermingled brain impulses stimulated by our memory.
The ”theory of threat simulation” signifies the dreams as a tool to interpret threatful events, and developing the behavior to avoid any damage from such events.
Despite these and multiple other theories on how and why dreams happen had been proposed over a long time, but, until recently, no strong evidence was available for the matter.
A recent study, published in the Journal of Neuroscience, suggests that dreams happen when, during deep sleep, your brain processes and interprets your daytime memories and experiences. Cristina Marzano, along with her colleagues at the University of Rome, is the very first to discover some insightful facts about how we remember our dreams. The neuroscientists suggest that recalling a dream is associated with certain types of brain waves.
To make their point, researchers enticed 65 students to sleep for two nights at their research lab. On the first night, all the students were let sleep and get accustomed to the sound-proof and temperature-controlled rooms. During the second night, researchers recorded, using the electroencephalography technique, the brain activity waves of all the students while they were sleeping.
We have four types of brain waves named ‘alpha’, ‘beta’, ‘theta’, and ‘delta’, and each wave form signifies a different electrical voltage in the brain. The research team recorded the brain waves of every participant, during each of the 5 stages of sleep. REM-sleep (rapid eye movement sleep) is the stage of sleep where we have most of our intense dreams.
Well, previous studies have already demonstrated that we better recall the dreams we have during the REM-sleep. But, it was found in this study by Cristina, that recalling a dream is also associated with increased ‘theta wave activity’ in the frontal cortex of the brain. This fact is very interesting because similarly increased theta wave activity is also observed when recalling our biographical memories while we are awake.
This analogy means that the neurophysiological mechanisms behind the dreams are the same as when we create and recall our memories when we are awake.
Yet, in another study by the same team of researchers, they measured the activity of different deep brain structures (using MRI) while the subjects were dreaming. They noticed an increased activity of the amygdala and hippocampus on nights when students had emotionally intense dreams. While the hippocampus is important to retrieve and interpret the memories, the amygdala plays a key role in processing the emotions attached to our memories.
The suggested link between our memories and emotions is also emphasized by another study, conducted at the Sleep and Neuroimaging Labs, UC Berkeley. It was found that long term deprivation from REM sleep (dreams) takes a toll on our ability to understand and manage our emotions.
Yet more recently, another study concluded that dreams are a function of the brain. Charcot Wilbrand Syndrome is a rare clinical disorder, in which the patient loses his ability to have dreams and no other significant symptoms of the disease. Such patients have a lesion in the right inferior lingual gyrus of their brains. This infers that dreams must either be generated or passed through this particular part of the brain, that processes the visual memories and emotions attached to them.
Connecting the dots from all the above-mentioned studies, it builds an interesting story about how and why you have dreams and the emotional perspectives of your dreams. Dreams are essential tools that process your emotions associated with your experiences and build memories of it. Dreams are very essential for mental health because if you were not to process your emotions, (especially the negative emotions) you might have suffered from anxiety and depression. That’s why prolonged deprivation from REM sleep can lead to several mental health disorders.
In short, dreams form a bridge that connects your experiences with emotions and memories. Happy dreams!