0125 GMT December 02, 2021
In their paper published in the journal Nature Neuroscience, the team describes experiments the conducted with volunteers wearing Electroencephalography (EEG) caps and what was revealed, according to phys.org.
For many years, there has been a consensus among sleep experts that humans experience dreams only during REM sleep cycles.
Now, it appears that such assumptions might be incorrect, as the researchers with this new effort found evidence of dreaming during other sleep cycles, as well.
To better understand sleep and when dreams truly occur, the researchers recruited 32 people who agreed to wear EEG caps as they slept in beds in a lab.
Each was awakened at different times depending on EEG readings, and were asked if they were dreaming and whether they could recall details about it.
In looking at the data, the researchers found that many of the volunteers reported dreaming during non-REM cycles, though most of the dreams were more difficult if not impossible to remember.
They also found a correlation between dreaming during both REM and non-REM cycles of low-frequency brain waves occurring in an area in the back of the brain they dubbed ‘the hot zone’.
This identification of a hot zone, the researchers claim, allowed them to predict when a person was dreaming.
The researchers next asked seven volunteers who were familiar with dream studies to spend between five and 10 nights in the lab sleeping with EEG caps on their heads.
This allowed the researchers to monitor how much of the time people were dreaming and when.
They report that they found that the volunteers dreamed approximately 71 percent of the time during non-REM sleep and 95 percent during REM cycles.
In yet another experiment, the researchers monitored 10 people as they slept and woke them at various stages of dreaming, which, they claim, allowed them to see that people were better able to remember their dreams if there was activity in the prefrontal cortex (which prior research has shown is linked with building memories) as the dream was occurring.