You might have searched for an explanation or meaning after waking up from a strange but realistic dream. A new study found that while the contents of your dream might mean nothing, they may help organize your brain.1
Dreams that involve fragments of memories could be a way for the brain to process waking experiences, according to the researchers.
“Dreaming at night may be just as important for your brain as gathering new experiences during the day. Remember that for every two hours you spend awake, perceiving new information, you sleep one hour, with no information coming in,” said Nicolas Deperrois, a PhD student in the computational neuroscience group at the University of Bern in Switzerland and lead author of the study.
The researchers also emphasized the importance of REM sleep, where dreaming takes place, for keeping the mind sharp.
What Is REM Sleep?
Rapid eye movement (REM) sleep is the last stage in a sleep cycle, characterized by vivid dreams, muscle paralysis, and eye movement. REM sleep occurs around 60-90 minutes after falling asleep, and this stage stretches longer in the second half of the night.
The Role of REM Sleep in Learning and Memory
If you’ve ever gone a day without sleep, you may have found it hard to remember certain events or retain new information. Research suggests that REM sleep is essential for consolidating memories.2
Thomas M. Kilkenny, DO, a sleep specialist and director of the Institute of Sleep Medicine at Staten Island University Hospital, told Verywell that the brain loves REM sleep in particular.
“If one were sleep-deprived and then allowed to sleep, they would spend a greater amount of time than usual in REM sleep,” he said.
What to Do to Resolve a Lack of Deep Sleep
While the exact role of dreaming is unclear, a potential reason for dreaming is to build and strengthen connections in the brain. Kilkenny said the evidence is in infants who spend over 18 to 20 hours a day sleeping to facilitate early brain development. And of the time asleep, babies are in REM sleep 50% of the time.
“It is thought that dream imagery helps to develop new neurologic connections in the brain while the infant is sleeping,” he said.
Deperrois suggested that there may be a scientific purpose for humans to continue dreaming beyond infancy.
“During childhood development, we do not only retain specific episodes but learn general concepts about the world, which build the major structure of our brain—learning how to recognize objects, walk or speak,” Deperrois said.
The Contents of Your Dream May Not Matter
In his research, Deperrois wanted to find an answer to the dreams that feel like a strange movie. He hypothesized that dreams create virtual experiences to help the brain learn about the world. A dream could come from one single memory or a mesh of multiple and unrelated memories.
His team used artificial intelligence to simulate the virtual experiences people have when asleep. While not directly tested on humans, Deperrois said the model is effective at making specific predictions on a behavioral and neuronal level.
While in an “awake state,” the model was shown various pictures, from boats to dogs. During non-REM sleep, the model showed that brain activity quiets down, and the brain repeated the stimulus that was presented earlier. In REM sleep, erratic and dynamic brain activity signals when a person is dreaming. During REM sleep, the objects were fused together and became more twisted.
Causes of Vivid Morning Dreams
Non-REM and REM sleep are both necessary for retaining the memory of an object. However, removing REM sleep or making dreams less creative in the model decreased the accuracy in identifying the object later.
The findings suggested that dreams aren’t used to retain specific memories, but rather, the merging of memories in vivid dreams helps the brain sort out its thoughts.
“It provides a hint of why our dreams often creatively combine elements from different episodes of our lives,” Deperrois said. “Generating new but realistic virtual experiences requires the brain to learn a lot about the structure of our world, a knowledge that is precious to navigate our environment while being awake.”
What This Means For You
Sleep carries many health benefits, ranging from purging waste products from the brain and decreasing stress to muscle recovery. There is also strong evidence that sleep is important for learning and retaining memory.
Deperrois and his colleagues are using the new findings to design a new experiment with human participants. Their goal is to look at how dreams affect other types of brain function, such as visual object representation. For example, they would measure how good people are at recognizing unfamiliar objects after being exposed to related objects the day before.
Since their research was not a clinical study, it’s too early to conclude that dreaming is essential for learning. But Deperrois said that dreaming is involved in the restructuring of our brain as we learn new concepts and skills.