Researchers at the Netherlands Institute for Neuroscience discovered why you will be better able to bear tomorrow what you are distressed about today.
Something frightening or unpleasant does not go unnoticed. In our brain, the so-called limbic circuit of cells and connections immediately becomes active. First and foremost, such experiences activate the amygdala. This nucleus of brain cells located deep in the brain can be regarded as the siren of the brain: attention! In order for the brain to function properly, the siren must also be switched off again. For this, a restful REM sleep, the part of the sleep with the most vivid dreams, turns out to be essential.
The researchers placed their participants in a MRI scanner in the evening and presented a specific odor while they made them feel upset. The brain scans showed how the amygdala became active. The participants then spent the night in the sleep lab, while the activity of their sleeping brain was measured with EEG, and the specific odor was presented again on occasion. The next morning, the researchers tried to upset their volunteers again, in exactly the same way as the night before. But now they did not succeed so well in doing this. Brain circuits had adapted overnight; the siren of the brain no longer went off. The amygdala responded much less, especially in those who had had a lot of restful REM sleep and where meanwhile exposed to the specific odor.