The brain is as complicated as its mysterious function of dreaming. And it doesn't always show if it's dreaming in a concrete way.
It is now just one signal away to tell if the person is dreaming and, therefore, in REM sleep.
Scientists from the University of California, Berkeley have detected a signal from brain activity, which distinguishes the dreaming stage from wakefulness. The dreaming stage used to be similar to that of an awake brain, which made it difficult to tell by using only electroencephalogram (EEG) data.
What's the noise?
EEG tests can show if a person is awake, deep-sleeping, or in REM sleep. Still, it is not sufficient to detect the dreaming stage in REM sleep and it takes doctor observation to check rapid eye movement and muscle tone contraction.
We tend to have most of our dreams during the REM sleep stage, while some may take place in NREM. However, EGG data can get confused due to the noise in the brain while in the REM and perceive the electrical activity as if the brain is awake.
It's kind of the trick the brain uses to deceive us, unintentionally.
“There is this background activity, which is not rhythmic, and we have overlooked that for quite a long time,” Jenna Lendner, first author of the study, declared. “Sometimes, it has been called noise, but it is not noise; it carries a lot of information, also about the underlying arousal level. This measure makes it possible to distinguish REM sleep from wakefulness by looking only at the EEG," she continued.
Started with a comparison
The study was conducted with the intention of monitoring people under anesthesia during surgery and understanding the differences of unconsciousness between unnatural and natural sleep.
“Anesthesia can have some side effects. If we learn a little bit about how they overlap — maybe anesthesia hijacks some sleep pathways — we might be able to improve anesthesia in the long run,” Lendner explained.
Now it turns out easier to monitor people during a coma and come out with deductions on their states "It could resolve, for instance, if someone was in a minimally conscious state, and they are not moving, and whether they are more alert than you think they are," Robert Knight, senior author of the study, added.