A study from the University of California (USA) published in the journalCurrent Biologyreveals that while we dream, brain chemistry linked to stress is turned off (norepinephrine drops) and the brain can process emotional experiences to“erase” or “soften” painful or unpleasant emotions stored in memory. This is deduced in a series of experiments carried out by researchers using magnetic resonance imaging. According to the study authors, the finding offers an interesting new explanation for why we dream.
“The phase of sleep in which there is dream activity -that is, in which we dream-, is based on a different neurochemical composition, and provides us with a form of therapy, a balm that eliminates the” sharp edges “of emotional experiences lived during the day, “says Matthew Walker, a neuroscientist at the University of California at Berkeley. This phase of sleep, better known asRem(Rapid Eye Movements), occupies 20% of the rest time of a healthy person.
In their study, Walker and his colleagues worked with 35 subjects who were shown emotional images at different times of the day. The experiments revealed that the images seen in the morning, after sleeping, had a much less intense emotional response. Specifically, they detected amarked reduction in amygdala reaction, brain structure that processes emotions, leaving the prefrontal cortex “rational” to take control of the emotional response of the subjects. “After sleeping the experiences of the previous day have reduced their emotional load; we feel better about them, we feel able to face them,” explains Walker.
Although humans spend about a third of our lives sleeping, there is still no clear scientific explanation for the physiological role of sleep. Walker and his team suggest that an answer to this mystery could come from the narrowrelationship between learning, memory and emotional regulation. In addition, they ensure that REM sleep patterns can be interrupted in post-traumatic stress disorders or depression, which would hinder the psychological recovery of these people.
