There's still a great deal of information about the effects of sleep on the brain that we don't yet understand, so any research that sheds light on this subject is exciting and potentially important. We know that sleep has restorative, cognitively-enhancing effects. We also know the absence of sleep can have detrimental effects on brain function. Recent studies in sleep-brain research have shown:
- A link between deep sleep and the formation of long-term memories. Researchers at Washington University School of Medicine were able to establish this direct link by manipulating a cluster of cells in the brains of fruit flies. After breeding the flies to sleep on demand, the researchers discovered that with sleep, fruit flies were able to convert new information into long-term memories. Without sleep, the fruit flies were only able to retain new information for a brief period, as short-term knowledge.
- Chronic insomnia may lead to damage in the brain. Another recent study in the sleep-brain connection revealed that chronic insomnia is associated with loss of grey-matter density in the human brain. Scientists in the Netherlands found a strong correlation between chronic insomnia and a decrease in grey matter in certain regions of the brain. Moreover, they discovered that the more severe the insomnia, the more significant the decrease in grey matter.
In a recent post -- "Can Sleep Help Heal Painful Memories?" -- I wrote about newly published research that showed REM sleep helps the brain to process emotional memories. In this study, people who slept after being exposed to emotionally charged images had a less intense reaction to seeing these images a second time, compared to people who saw the images twice without sleeping between viewings. Measuring brain activity using MRI, researchers observed a quieting of activity in the region of the brain that processes emotions, indicating that during REM sleep the brain is "soothing" itself of stress.
This latest study may provide another important piece of the puzzle as we work to understand how sleep affects our brain chemistry and brain function. This is also one of those studies that answers a question only to raise many more. Does this insight into the role of sleep in processing emotions provide us a glimpse into why we dream? For people who have suffered severe emotional trauma, is the "re-living" of those experiences connected to their sleep, and to the repetitive nightmares that often accompany significant emotional distress?The implications of these most recent findings could be significant for people with a wide range of conditions. People with:
- psychiatric disorders
- who live and work under prolonged, chronic and intense stress
- who suffer from mood disorders, depression and anxiety
- post-traumatic stress disorder
All of these and others stand to benefit from a greater understanding of how sleep can help process emotions.
Stress and emotional upheaval are part of everyone's lives at some point, of course, so this news is relevant for every one of us. As science works toward greater knowledge of how sleep works within the brain, let's take this moment to remember just how powerful -- and helpful to your wellbeing, emotionally and physically -- a good night of sleep can be.
Michael J. Breus, PhD
The Sleep Doctor™
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