By exposing us to our bad memories when our brain can better handle them:
During REM sleep, which is the dreaming stage of sleep, the brain stops releasing stress chemicals. Now a new study finds that as we dream we can even soothe our stressful associations to certain experiences.
Scientists scanned the brains of 35 subjects while they viewed emotionally arousing images. Half of the subjects viewed the images in the morning and again in the evening of the same day. The other half viewed the same images in the evening and then again the next morning after sleeping.
Those who slept between viewings reported a significant decrease in their emotional reaction to seeing the images the second time. And brain scans corroborated the self-reports, showing a reduction of activity in the amygdala, an area responsible for processing emotions.