Insufficient sleep harms the brain

Students and businessmen are often miss a good night’s sleep with a view to performing brilliantly in exams and securing big contracts respectively, but this may adversely affect their brain health in later life, according to two new studies.

Published in the journal Science, one of the studies saw microdialysis experiments being conducted on mice, and found that extracellular amyloid-beta levels in the brain fall during slumber and rise with wakefulness.

Dave Holtzman, Washington University, St. Louis, Missouri, observed during the study that these Abeta dynamics rely on the hormone orexin, and that forcing animals to sleep or stay awake decreases or increases Abeta plaque formation accordingly in a mouse model for Alzheimer disease.

In a previous study, Holtzman had shown that synaptic activity triggers Abeta release, suggesting that the sleep-deprived mice in the current study churned out more Abeta because their brains were revved up longer than usual.

Although formally proving this is hard, a rat electrophysiology study published in the journal Neuron seems to lend support for that idea.