It's not quite "Inception," but new research has allowed scientists to "read" some people as they dream.
Using brain imaging, researchers at the Max Planck Institute of Psychiatry in Germany said they were able to compare the brain activity of "lucid dreamers" as they entertained the same thoughts awake and asleep. The brain activity was similar, if weaker during sleep, the researchers said.
Lucid dreamers are sleepers who are aware that they are dreaming and can deliberately control their dream actions. According to the researchers, lucid dreaming is a learned skill, one very useful to scientists trying to understand the secrets of dreams.
"The main obstacle in studying specific dream content is that spontaneous dream activity cannot be experimentally controlled, as subjects typically cannot perform pre-decided mental actions during sleep," study researcher Michael Czisch said in a statement. "Employing the skill of lucid dreaming can help to overcome these obstacles."
Researchers at the Munich-based institute said they recruited six practiced lucid dreamers, all of them adult men. The volunteers slumbered in a functional magnetic resonance imaging (fMRI) machine, which measures blood flow to regions of the brain. An increase in blood flow suggests that particular region of the brain is active and working. Meanwhile, the men were asked to make a series of hand-clenching movements and eye movements (beneath closed eyelids) when they entered into a lucid dream-state.
The sensory and motor areas activated by those movements in wakefulness also lit up the brain scans during the movements in lucid dreams. However, the dream activation was only about half as strong, meaning it was either weaker or confined to smaller segments of the brain.
Scanning the brains of lucid dreamers eventually may allow researchers to guess at the content of dreams by analyzing a slumberer's brain activity. Another group of scientists already has made movies reconstructing the things that awake people have seen, by analyzing their brain waves.
The new study was published Thursday (Oct. 27) in the journal Current Biology.
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Stephanie Pappas is a contributing writer for Live Science, covering topics ranging from geoscience to archaeology to the human brain and behavior. She was previously a senior writer for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association. Stephanie received a bachelor's degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz.