How sleep loss can damage your brain's wiring

Sleep loss damages the fatty insulation protecting the nerve cells in our brain, according to a paper published in the journal Proceedings of the National Academy of Sciences. The research also explains why we often feel slow and groggy after a bad night's sleep.

Most of us will experience sleep loss at one time or another and suffer the consequences of tiredness and slower reactions the next day. The biological mechanisms for these are not well understood and often attributed to tired or overworked neurons. Researchers thought there might be other factors at play, so they decided to investigate.

The team studied MRI scans of 185 volunteers who self-reported poor sleep quality, which confirmed previous studies that found a link between inadequate sleep and changes in the structure of white matter (the bundles of nerve fibers that carry impulses between neurons). To find the cause, the researchers ran tests on rats that had their sleep restricted for ten days.

First, they performed electrical tests on the rats' brains and discovered that sleep loss caused nerve signals to take around 33% longer to travel between the two hemispheres. Later analysis of brain tissue found a likely cause. The myelin sheaths were much thinner. These are the fatty layers that wrap around nerve fibers to insulate them and speed up electrical signals.

Analysis of the lipid composition of the brain and the activity of genes that regulate oligodendrocytes revealed that the main issue was cholesterol deficiency. The scientists focused on these cells because they are responsible for creating and maintaining myelin. They found that cholesterol, which is essential for keeping the insulation thick and healthy, was not being properly transported to the myelin sheaths, so they were thinner and less able to do their job.

To test this, the researchers administered a compound called cyclodextrin, which works to flush trapped cholesterol out of cells and back into circulation. This prevented myelin sheaths from thinning any further and eliminated the roughly 33% delay in signal speed. In behavioral tests, the rodents performed just as well as those that were well-rested.

It is too early to talk about treatments for sleep deprivation based on the conclusions of this study. However, if confirmed in humans, the results would open up new possibilities, as the researchers acknowledge in their paper.

Reyila Simayi et al, Sleep loss induces cholesterol-associated myelin dysfunction, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2523438123

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Megan N. Jamison Hart et al, What's in your water? A comparative analysis of micro- and nanoplastics in treated drinking water and bottled water, Science of The Total Environment (2026). DOI: 10.1016/j.scitotenv.2025.181148

Stimulating the brain with electromagnetic therapy after stroke may help reduce disability
Electromagnetic network-targeted field (ENTF) therapy combined with physical therapy led to a 22% higher rate of freedom from disability in stroke survivors compared to sham treatment, with improvements across disability levels and no serious adverse effects. Findings are based on two small trials, indicating the need for larger studies to confirm efficacy.

The analysis found:

• The percentage of participants who achieved freedom from disability was 22% higher in the ENTF group compared to the group that received the sham treatment (33.8% versus 11.9%, respectively).
• Measurable improvements were also seen in ENTF participants' disability levels across the full range of disability outcomes, with both less moderately to severe disability (mRS of 3–5) and less moderate disability (mRS of 2).
• No serious adverse effects were reported among participants who received ENTF therapy.

https://medicalxpress.com/news/2026-01-brain-electromagnetic-therap...