Restful REM Sleep Can Turn Off The Brain Siren, Claims Study

Brain News: A new study finds that restful REM sleep -the part of the sleep with the most vivid dreams – turns out to be essential if you want to deal with something frightening or unpleasant and switch off the brain siren.

Whenever we are upset with something, it immediately activates the amygdala and limbic circuit of cells and connections in our brain, this is called the brain siren. Only when this siren is switched off brain can again function properly.

Researchers at the Netherlands Institute for Neuroscience placed their participants in an MRI scanner in the evening and presented an unpleasant odour. The brain scan showed that the amygdala became active. The participants spend the whole night in the lab, while their sleeping brain was measured with EEG and the bad odour was presented again on occasion.

The next morning the experiment was repeated but failed to upset the volunteers. The participants had restful REM sleep, so the brain siren no longer went off when an unpleasant odour was presented in the morning. Their brain circuits had not adapted well overnight. When the same experiment was conducted with restless sleepers, their brain circuit failed to adapt overnight and the siren of the brain continued to sound the next morning. The amygdala responded much less, especially in those who had had a lot of restful REM sleep

The findings conclude that Restless REM sleep is essential for recovery and adaptation to distress. The study results have transdiagnostic importance for people with insomnia PTSD and other mental disorders, who have restless REM sleep and a hyperactive amygdala.

To Know More, You May Refer To:

Wassing, R., Lakbila-Kamal, O., Ramautar, J. R., Stoffers, D., Schalkwijk, F., & Van Someren, E. J. (2019). Restless REM sleep impedes overnight amygdala adaptation. Current Biology, 29(14), 2351-2358.e4. https://doi.org/10.1016/j.cub.2019.06.034