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A neuroscience study has upended what we know about dreaming. It identifies a “hot zone” in the brain that indicates when dreams are occurring, and describes how the signals in the brain can even predict what a person is dreaming about.
Read more: How to manipulate your dreams
Typically, in dream studies, a person is identified as dreaming when they are in rapid-eye-movement (REM) sleep. In the brain, this is indicated by high-frequency electrical activity. We do know, however, that dreaming also occurs during non-REM sleep when there is low-frequency activity but the nuts and bolts behind this capability have not been well understood, until now.
A study from the Wisconsin Institute of Sleep and Consciousness (WISC), published in Nature, shows that when dreaming was reported in both REM and non-REM sleep, a decrease in low-frequency activity occurred in the posterior cortical region, an area at the back of the brain associated with spatial reasoning and attention. The neuroscientists say they were able to correctly predict whether a volunteer was dreaming 92 per cent of the time, simply by monitoring activity in this “hot zone”. “[The region] may constitute a core correlate of conscious experiences in sleep,” they write.
Picking up further on this “hot zone”, the team was also able to begin breaking down the contents of a dream by monitoring which regions were activated.
“We’ve been able to identify the brain areas that correspond to specific dream contents (like faces, spatial setting, movement and speech) during well-established sleep,” said co-author Francesca Siclari in a statement.
Forty-six subjects at the WISC lab had their sleep monitored using an EEG net worn on the head, covered in 256 electrodes. The volunteers were woken periodically, then asked whether or not they had been dreaming. They first looked specifically at REM and non-REM sleep, noting that volunteers reported they had dreamt when the “hot zone” was activated, regardless of what state of sleep they were in.
In a second experiment, the volunteers reported the content of their dreams, based on key themes the neuroscientists could identify in the posterior cortex: the aforementioned faces, spatial setting, movement and speech. If a volunteer reported hearing speech in their dream, it would correlate with the region of the brain responsible for language and understanding; if they dreamt about people, the region responsible for facial recognition was ignited. This means, says Siclari, that we probably use the same areas of the brain during dreaming, as we do when awake, explaining the sense of reality a dream often portrays for an individual.
Co-author and a professor of psychiatry at the lab, Giulio Tononi said these experiments will help us “zoom in on the brain regions that truly matter for consciousness”. The study, he believes, could help us understand the purpose of dreams, and perhaps even the basis of consciousness one day. WIRED has contacted the researchers for more information about the implications of this research.
This article was originally published by WIRED UK
