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...." medicalxpress.com/news/2026-… 👇 "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. Cholesterol bottleneck 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." See: Reyila Simayi et al, Sleep loss induces cholesterol-associated myelin dysfunction, Proceedings of the National Academy of Sciences (2026). DOI: 10.1073/pnas.2523438123