Dreamful Sleep May Ease Painful Memories
Researchers postulated that dreams help people recover from traumatic experiences by effectively shutting down stress mechanisms associated with it, therefore the brain can process emotional processes more easily to resolve the trauma. The shutting-down of stress mechanism happens during REM (Random Eye Movement) sleep, which comprises only 20 percent of an entire healthy sleep. This REM sleep is significantly reduced when sleep becomes fragmented, or during times of insomnia.
To uncover whether this truth applies, researchers recruited 35 healthy young adults and divided them into two groups. All were shown 150 emotional images, viewed twice and 12 hours apart, while having an MRI scan to show brain activity. Half of the group was shown images in morning and again in evening without sleeping in between. The rest were shown images in the evening and again the next morning after a full night of sleep. In addition, the participants were wired to ECG while they slept, with measures the length of REM sleep.
In general, MRI scans shows reduced emotional reaction to images on the group that were allowed to sleep. Deeper analysis shows dramatic reduction of activity in the part of the brain called Amygdala, the primary center that processes memory of emotional reactions. ECG readings also shows that REM sleep significantly reduce stress hormones in the brain that are acquired during the day, notably norepinephrine. Norepinephrine is an adrenergic hormone that is released during times of stress, heightening blood pressure, heart rate and blood sugar. Being a stress hormone, it is also associated with nightmares.
The reason why people with PTSD do not become well after a night of restful sleep is because they have high levels of stress hormones, which makes flashbacks and nightmares very likely. The experiment also shows an insight on
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Filed under Mental Illness, Post Traumatic Stress Disorder by on Nov 28th, 2011. 
