By Jasmine Aguayo
Before Freud, people believed that dreams were a celestial experience. He was the first to propose that, indeed, our dreams were a product of subconscious thoughts, feelings, and desires (Freud, 1900). Soon after, science sought to unravel the delicate intricacies of our brain and discovering its many functions remains an ongoing investigation.
Matthew Walker, Ph.D., a professor of neuroscience and psychology at UC Berkeley and the director of its Sleep and Neuroimaging Lab has used groundbreaking research to disentangle the functions of the sleeping mind.
Phases of Sleep
When we sleep well, we dream. Prior to reaching a dream state, we drift between Non REM (non-rapid eye movement) phases of relaxation. At level 1 (Alpha), there is an alternation between awake and light sleep. The second phase of sleep (Theta) consists of lower frequency brain waves with a higher amplitude. Levels 3 & 4 (Delta) are referred to as slow wave sleep with an even lower frequency and high amplitude waves. Following these stages, we reach REM (Rapid Eye Movement) sleep, which mimics the awake state. Most often visions drift through our head causing twitches, jerks, subtle movement, or slurred speech.
Some argue that dreaming is a by-product of REM sleep and has no further importance. Recent studies have proven this to be wrong. In fact, a lack of dreaming can be detrimental to our mental and emotional health.
Sleeping to Heal
Walker proposed a theory, “REM-sleep dreaming takes the painful sting out of difficult, even traumatic emotional episodes you have experienced during the day.” [Walker. pp 207]
A biological cousin to adrenaline, noradrenaline (a.k.a. norepinephrine) cannot be produced when we dream; This is the only exception. Any other time of the day or night, it can be made by the brain and trigger anxiety.
During REM-sleep, activity is concentrated in the amygdala and hippocampus which are (respectively) the emotional and memory recall centers of the brain. Could our body be creating a chemical stress-free atmosphere to sort through difficult experiences?
This is what Walker wanted to find out. He matched this theory with experiments.
Walker randomly divided participants into two equal groups. Both groups watched “emotional images” while their brains were being monitored by an MRI scanner. The first group saw the images in the morning with no sleep in between. The second group observed them in the evening and slept overnight. 12 hours later, both groups watched it again. The individuals who slept had a reduced emotional reaction the second time around, suggesting that “sleeping on it” functioned as a natural therapy.
This begs the question, are some mental conditions, specifically anxiety disorders, directly related to sleep disruption? Most include the symptom of poor sleep or insomnia. Those with PTSD experience severe nightmares and flashbacks. If the symptoms are more closely related to the cause, then his hypothesis holds credence.
Walker theorized, “a contributing mechanism underlying the PTSD is the excessively high levels of noradrenaline within the brain that blocks the ability of these patients from entering and maintaining normal REM-sleep dreaming. As a consequence, their brain at night cannot strip away the emotion from the trauma memory, since the stress chemical environment is too high.” [Walker. pp 212]
A fortunate stroke of serendipity occurred. Walker met Dr. Murray Raskind, a physician from the US Department of Veterans Affairs hospital in Seattle. Raskind prescribed a blood pressure medication to his patients which accidentally stopped their PTSD symptoms. This drug, called Prazosin, has the side effect of suppressing noradrenaline. Due to the collaboration of Walker and Raskind, Prazosin is now the official drug used to treat PTSD.
Dream for a Brighter Tomorrow
Dreaming offers us the emotional strength to move past experiences, but it also prepares us for future situations. Another study Walker lead, this time on sleep deprivation, demonstrated how much REM sleep affects our ability to read social-emotional cues.
“The sleep deprived participants slipped into a default of fear bias...friendly looking faces were menacing. The outside world had become a more threatening and aversive place.” [Walker. pp 216]
Lack of emotional strength leads to this pessimistic perspective of others. This only feeds into maladaptive patterns of thinking.
As society focuses on productivity over self nurture, anxiety and negativity are spreading like wildfire. People who we depend on for health and safety are often sleep deprived; Medical professionals, law enforcement, and military personnel are overworked. Mental illness is at an all-time high, even in children. It’s time we all slowed down and slept well. Our well being depends on it.
Walker, Matthew. Why We Sleep: Unlocking the Power of Sleep and Dreams.
1st ed., Scribner, 2017.
Gujar, McDonald, Nishida, Walker.
Cerebral Cortex January 2011; 21:115-121
Advance Access publication April 26, 2010
Freud, S. (1900). The Interpretation of Dreams. [online] Classics in the History of Psychology. Available at: http://psychclassics.yorku.ca/Freud/Dreams/dreams.pdf [Accessed 12 Oct. 2015].