Painful Memories Reduced by Dreaming

by healthypages on 13/01/2012 - 01:29 pm |

The particularly bad part of painful experiences can be dealt with by dreaming suggests as new study. Researchers from the University of California, Berkeley, found that during REM sleep which is the dream phase of sleep the brain is able to process the more emotional experiences because the stress chemistry of the body has stopped working at that time.

This process that takes place in the dream state may be a reason why post-traumatic stress disorder (PTSD) sufferers find it difficult to return to normal after a distressing experience such as a war zone. Such people often have recurring nightmares and have difficulty sleeping soundly.

From UC Berkeley, senior author of the study and associate professor of psychology and neuroscience, Matthew Walker said, "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."

Connecting this with PTSD sufferers, Walker explained 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."

To carry out the study 35 adults were selected and separated into two groups. Both groups were shown 150 images of emotional content once every 12 hours, but one group was shown them in the morning and evening with no sleep in between, whereas the other group was shown them in the evening and the morning with a good nights sleep in between. The ones who had a sleep in between the two viewings had a much lower emotional reaction to the set of images shown in the morning compared to the group who had no sleep in between.
All participants underwent MRI scans while viewing the images so brain activity could be measured.

Explaining the results, Walker said: "We know that during REM sleep there is a sharp decrease in levels of norepinephrine, a brain chemical associated with stress," adding that "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."