What is the role of sleep?

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Offline cheryl j

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What is the role of sleep?
« on: 09/06/2013 13:30:25 »
From time to time the topic of sleep comes up on this forum, and why we need it. The journal Nature recently had a big feature on sleep (May 23). Here are some interesting tidbits from the article:

Sleep and memory - During sleep memories encoded in the hippocampus are transferred to other regions of the brain where they are interpreted and stored. It is not just a passive storage process. Memories are edited, adding or removing content, or attaching emotional tone. The experimental support for this is the effect of sleep on learning, including motor skills, but also experiments in which imaging shows neurons oscillating in the hippocampus  that seem to indicate memories being played back from earlier in the day. But as researchers point out, interpretation of the studies is complicated because "We don't know how (the brain) does any of this because no one knows how a memory is formed"..."If we could pinpoint the location of a single memory, we could figure out how sleep changes it."

During sleep, ATP in the brain is regenerated from ADP which increases during the day. It is also adenosine that triggers neuron activity in a part of the brain called the VLPO, which releases GABA to inhibit the arousal system.

Chronic Sleep deprivation is associated with increased obesity, diabetes, cardiovascular disease, and cancer. Experimental evidence is based on increased substances like AKT, a protein involved in insulin signaling, other hormones, or increases in inflammatory proteins like CRP and inflammatory cytokines. But this research is also problematic - are these changes the direct result of lack of sleep or what people do when they are not sleeping (like eating at night) or do factors that cause certain disease states also interfere with sleep? The same correlation problems plague studying the connection between mood disorders and sleep.

 But one study showed that people with high blood pressure reduced it to normal by extending their sleep one hour per night for six consecutive weeks and I thought that was rather impressive.

Some people need more sleep than others - subjects positive for a particular gene allele were more vulnerable to the effects of sleep loss.

There was also a section on new sleep drugs which may have fewer side effects than barbs and benzos, and a section on the effect of artificial lighting on human sleep. Contrary to what I would have guessed, soft blue light is a wake up signal to the brain. If you want lighting that interferes less, red shades are better.
« Last Edit: 09/06/2013 23:18:37 by chris »