Animal study shows sleeping brain behaves as if it’s remembering

During sleep, even anesthesia–induced sleep, part of the brain appears to continue working to process information and cement memories. That’s according to a study (subscription required) published yesterday in Nature Neuroscience, and the findings, say researchers, could offer new insights into better understanding Alzheimer’s disease.

Health Day reports on the UC Los Angeles research:

For the study, which was performed on mice, the researchers measured the activity of single neurons from three parts of the brain involved in memory formation in order to identify which brain region was activating other areas of the brain and how this activation was spreading.

The investigators discovered that the entorhinal cortex has what is called persistent activity, which is believed to be involved in working memory when people are awake, such as remembering a phone number or following directions.

…

Persistent activity in the entorhinal cortex during sleep may be a way to unclutter memories and delete information that was processed during the day but not needed, which results in important memories becoming prominent and readily accessible, [senior author, Mayank R. Mehta, PhD,] suggested.

The findings are important because people spend one-third of their lives sleeping, and a lack of sleep causes various health problems, including learning and memory problems, Mehta said. The researcher also noted that Alzheimer’s disease starts in the entorhinal cortex and these patients are known to have sleep problems.

Related to this, a previous mouse study done at Stanford showed that fragmented sleep can cause memory impairment.

Previously: Is quietly resting as helpful to your brain as sleeping?, Experts discuss possible link between sleep disorder and dementia and In mice, at least, uninterrupted sleep is critical for memory
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