Image of the Week

The Fibers That Slow Down the Brain

  • Published21 May 2019
  • Author Charlie Wood
  • Source BrainFacts/SfN
Image of amyloid fibrils seen in a lab sample created on mica
Dr. Wei-Feng Xue

Proteins are little molecular machines that make our minds and bodies tick, but when their parts pile up they might gum up the works. These strings, known as amyloid fibrils — seen here in a lab sample created on mica — form when leftover pieces of protein chain together. Excess strands can clump into plaques, which are associated with a range of diseases including Alzheimer’s disease, Creutzfeldt-Jakob disease (mad cow), and Parkinson’s disease — although researchers aren’t sure whether the fibrils are a cause or a side effect. 

Billionths of a meter thick yet tough as silk or steel, the unwanted threads are hard to destroy. Fortunately, your brain may have a natural way of clearing out the variety linked with Alzheimer’s disease: a good night’s sleep. The flow of fluids in the heads of mice, for instance, increases while dozing, literally flushing away amyloid fibrils. And in humans, staying awake for 31 hours straight appears to cause a five percent buildup.



Beil, L. (July 2018). The brain may clean out Alzheimer’s plaques during sleep. ScienceNews, 194(2), 22. Retrieved from

Rambaran, R. N., & Serpell, L. C. (2008). Amyloid fibrils: abnormal protein assembly. Prion, 2(3), 112–117. Retrieved from PubMed. (19158505)

Xie, L., Kang, H., Xu, Q., Chen, M. J., Liao, Y., Thiyagarajan, M., … Nedergaard, M. (2013). Sleep Drives Metabolite Clearance from the Adult Brain. Science, 342(6156), 373. doi: 10.1126/science.1241224

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