CT Daily

Dreaming away painful memories

Heather Rudow November 29, 2011


The best way to get past a traumatic experience might be to sleep on it. A University of California, Berkeley, study focusing on the importance of REM sleep found that dream sleep can lessen the pain of certain memories and might be pivotal in helping people who suffer from post-traumatic stress disorder (PTSD).

Researchers had 35 participants view 150 emotional images for the study, twice at 12 hours apart, while an MRI scanner measured their brain activity. They were split into two groups: Half of the participants viewed the images in the morning and again in the evening and stayed awake between the two viewings; the other half viewed the images in the evening and again the next morning after receiving a full night of sleep.

“Those who slept in between image viewings reported a significant decrease in their emotional reaction to the images. In addition, MRI scans showed a dramatic reduction in reactivity in the amygdala, a part of the brain that processes emotions, allowing the brain’s ‘rational’ prefrontal cortex to regain control of the participants’ emotional reactions. In addition, the researchers recorded the electrical brain activity of the participants while they slept, using electroencephalograms. They found that during REM dream sleep, certain electrical activity patterns decreased, showing that reduced levels of stress neurochemicals in the brain soothed emotional reactions to the previous day’s experiences.”

Said researcher Matthew Walker: “The dream stage of sleep, based on its unique neurochemical composition, provides us with a form of overnight therapy, a soothing balm that removes the sharp edges from the prior day’s emotional experiences. During REM sleep, memories are being reactivated, put in perspective and connected and integrated, but in a state where stress neurochemicals are beneficially suppressed. … We know that during REM sleep there is a sharp decrease in levels of norepinephrine, a brain chemical associated with stress. By reprocessing previous emotional experiences in this neuro-chemically safe environment of low norepinephrine during REM sleep, we wake up the next day, and those experiences have been softened in their emotional strength. We feel better about them, we feel we can cope.”

He added that this can be telling for patients with PTSD, in that when “a flashback is triggered by, say, a car backfiring, they relive the whole visceral experience once again because the emotion has not been properly stripped away from the memory during sleep.”

Source: UC Berkeley

Heather Rudow is a staff writer for Counseling Today. Email her at hrudow@counseling.org.

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