The new research demonstrates that these brain regions (including the part of the brain impacted by narcolepsy) are among the first casualties of neurodegeneration in Alzheimer's disease, and therefore that excessive daytime napping -- particularly when it occurs in the absence of significant nighttime sleep problems -- could serve as an early warning sign of the disease. In addition, by associating this damage with a protein known as tau, the study adds to evidence that tau contributes more directly to the brain degeneration that drives Alzheimer's symptoms than the more extensively studied amyloid protein.
"Our work shows definitive evidence that the brain areas promoting wakefulness degenerate due to accumulation of tau -- not amyloid protein -- from the very earliest stages of the disease," said study senior author Lea T. Grinberg, MD, PhD, an associate professor of neurology and pathology at the UCSF Memory and Aging Center and a member of the Global Brain Health Institute and UCSF Weill Institute for Neurosciences.
Study - August - Alzheimer - Dementia - Author
In the new study, published August 12, 2019 in Alzheimer's and Dementia, lead author Jun Oh, a Grinberg lab research associate, and colleagues precisely measured Alzheimer's pathology, tau protein levels and neuron numbers in three brain regions involved in promoting wakefuless from 13 deceased Alzheimer's patients and seven healthy control subjects, which were obtained from the UCSF Neurodegenerative Disease Brain Bank.
Compared to healthy brains, Oh and colleagues found that the brains of Alzheimer's patients had significant tau buildup in all three wakefulness-promoting brain centers they studied -- the locus coeruleus (LC), lateral hypothalamic area (LHA), and tuberomammillary nucleus (TMN) -- and that these regions had lost as many as 75 percent of their neurons.
Brain - Degenerating - Wakefulness-promoting - Network - Oh
"It's remarkable because it's not just a single brain nucleus that's degenerating, but the whole wakefulness-promoting network," Oh said. "Crucially this means that the brain has no...
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