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Can Sleep Help Heal Painful Memories?

The link between sleep and memories

Here's some truly fascinating sleep news, the kind that shows just how deeply sleep can affect every facet of our lives. Scientists at the University of California, Berkeley examined the relationship between sleep abnormalities and the brain areas related to emotions. They discovered that REM sleep processes emotional experiences, so that these experiences feel less painful, difficult, and emotionally charged after sleep.

Thirty-five adults participated in the study, all in good health. Researchers divided the participants into two groups. Both groups were shown the same series of 150 emotionally charged images, while researchers monitored brain activity with MRI. Each group was shown the entire series of images two times, with a 12-hour break between viewings. One group saw the images first in the morning, and again in the afternoon, and they stayed awake during the 12-hour interim period. The other group saw the images for the first time in the evening, followed by a full night of sleep, during which their brain activity was monitored by electroencephalogram. Upon awakening, the second group was shown the images a second time. Researchers found that exposure to REM sleep had a dramatic effect on people's reaction to the images:

  • People who slept between seeing the emotional images reported a decrease in the intensity of their emotional reaction the second time, compared to those who did not sleep
  • Brain scans during sleep showed that during REM sleep the brain's electrical activity slowed, essentially "soothing" the brain of stress.
  • MRI showed a significant decrease in the region of the brain that processes emotions. This decrease corresponded with an increase in activity of the brain's center for cognition, rational thought, and decision making.

Based on these results, it's as though REM sleep allows the brain to have some control of an emotional memory.

This is a single study, and we need to see more research on this subject. But think for a moment about the implications of these results. Sleep problems and sleep disorders—from insomnia and sleep apnea to sleep deprivation and restless leg syndromes—can all increase risks for other health problems, from obesity to diabetes to heart disease. They also can affect mental health. One thing all sleep problems seem to have in common is in bringing about a feeling of being overwhelmed, or of having difficulty coping well with the demands of daily life. Anyone who has ever run short on sleep, or weathered a string of sleepless nights, will know what I'm talking about. Irritability, emotional fatigue, distractedness, short-temperedness—these feelings are common enough with disordered sleep as to be considered universal.

What if this possible function of REM sleep—to manage and soothe emotional experiences from our waking lives—is at play here? Is the absence of REM sleep a factor in the emotional and mental toll that sleeplessness takes on us? A greater understanding of this possible connection could have a profound effect on how we view, and treat, sleep problems and the secondary effects of sleeplessness.

So remember, as I always say, it is truly better to "sleep on it" to feel better.

Sweet Dreams,

Michael J. Breus, PhD

The Sleep DoctorTM

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