We fall, we are pursued and are unable to move, we want to scream. But no sound comes out, a loved one dies or suddenly disappears. These are scenarios that probably everyone has experienced in their dreams at some point. If nightmares recur more often than once a week, they are considered nightmare sleep disorders. Around 5% of the adult population in Germany suffer from this disorder, according to statistics.
On the other hand, having a nightmare once in a while might even be good for us. Because, as researchers from the University of Geneva (UNIGE) and the Geneva University Hospitals (HUG) in Switzerland in collaboration with the University of Wisconsin (USA) have now discovered, these bad dreams have a purpose. They prepare us to face situations that we are afraid of in real life.
Consciousness does not distinguish between dreams and real life
Michael Schredl is a Mannheim-based dream researcher and author of the book Träume – Unser nachnachtliches Kopfkino (Dreams – Our Nightly Cerebral Cinema). He stated as early as 2014 that human consciousness is incapable of distinguishing between dream and reality. Dream consciousness and waking consciousness are completely identical in this respect. Scientists in Switzerland have now delved further into this phenomenon. They have identified in a study which brain areas are activated when people feel fear in their dreams.
They analyzed the brain activity of 18 volunteers with the help of an electroencephalogram (EEG) in a sleep laboratory. The researchers woke them up several times during the night. Every time the participants were awakened, they had to answer a series of questions, such as: “Did you dream? And, if so, did you feel scared?” Waking them up during their dreams is essential because the brain erases dreams from memory during REM sleep. This makes it almost impossible to answer questions about these the next day.
In their tests, the scientists used High Density Electroencephalography whereby several electrodes are positioned on the skull. These are used to measure brain activity. They discovered that certain regions of the brain are responsible for the formation of dreams. Whereas other regions are activated depending on the content of a dream, like perceptions, thoughts or emotions.
The insular cortex and the cingulate cortex
Researchers were able to identify two brain regions that were particularly active during nightmares. They did this by assessing brain activity on the basis of the EEG. These brain regions are the insular cortex and the cingulate cortex. The insular cortex is also triggered automatically when someone becomes scared while they’re awake. The cingulate cortex plays a role in preparing flight responses in threatening or frightening situations. “For the first time, we’ve identified the neural correlates of fear when we dream and have observed that similar regions are activated when experiencing fear in both sleep and wakeful states,” Lampros Perogamvros explains. He is senior clinical lecturer at the HUG Sleep Laboratory, Department of Pneumology.
The researchers then explored a possible link between anxiety that occurs during a dream and emotions that occur during wakefulness. They gave each of the 89 participants a week-long dream diary. The participants were asked to write down every morning after waking up if they remembered their dreams and the feelings they felt, including fear. At the end of the week, magnetic resonance tomography (MRI) was used to measure the participants’ brain activity. They were shown various images while undergoing the MRI. These included “emotional-negative images” such as assaults, as well as neutral images. The aim was to find out which areas of the brain were more active in the event of anxiety. And whether the activated area had changed depending on the emotions that the participants had experienced in their dreams.
It turned out that the longer a someone had felt fear in their dreams, the less the insula, cingulate and amygdala were activated when the same person looked at the negative images. “In addition, the activity in the medial prefrontal cortex, which is known to inhibit the amygdala in the event of fear, increased in proportion to the number of frightening dreams,” says Virginie Sterpenich, a researcher with the Department of Basic Neurosciences at UNIGE.
New approaches to therapy?
The scientists state that these results prove the very strong link between the emotions we feel while we’re asleep or awake. Plus they also confirm a long-held neuroscientific theory about dreams. That we simulate frightening situations while we are dreaming. We do this so that we are better able to respond to these when we’re awake. “Dreams may be considered as a real training for our future reactions and may potentially prepare us to face real life dangers,” Perogamvros states.
Based on the new findings, the researchers now want to examine whether these findings can potentially lead to new forms of dream therapy for the treatment of anxiety disorders. They also want to study nightmares as part of this research. In contrast to bad dreams, where the level of anxiety is moderate, nightmares disturb sleep because of the excessive anxiety that they cause. This can even have a negative effect on people when they wake up. Perogamvros stresses: “We believe that when a certain threshold of anxiety is exceeded in a dream, it loses its useful role as an emotional regulator.”