of sleep-dependent low-frequency (<0.1 Hz) global brain activity in
the clearance of Alzheimer's disease-related toxin buildup is presented
in research published on 1st June 2021 in the open access journalPLOS Biologyby
Xiao Liu and colleagues at The Pennsylvania State University. This
neuronal activity was more strongly linked with cerebrospinal fluid flow
in healthy controls than higher risk groups and patients, and the
findings could serve as a potential imaging marker for clinicians in
development of Alzheimer's disease is believed to be driven by the
buildup of the toxic proteins amyloid-β and tau in the brain. The
brain's glymphatic system plays a crucial role in clearing these toxins
and previous work has shown a possible relationship between
sleep-dependent global brain activity and the glymphatic system by
showing this activity is coupled by cerebrospinal fluid flow essential
for the glymphatic system.
118 subjects in the Alzheimer's Disease Neuroimaging Initiative
project, the researchers measured this global brain activity and
cerebrospinal fluid flow as well as looking at behavioral data.
Individuals underwent resting-state fMRI sessions two years apart, and
the team compared their findings with neurobiological and
neuropsychological markers related to Alzheimer's disease, such as
levels of the toxic protein amyloid-β.
strength of the connection between brain activity and cerebrospinal
fluid flow was weaker in individuals at a higher risk or who had already
developed Alzheimer's disease. Additionally, this weaker connection was
associated with higher levels of amyloid-β and disease-related
behavioral measures two years later. This suggests an important role for
sleep-dependent global brain activity in the clearance of brain waste,
and its connection to cerebrospinal fluid flow could be helpful as a
future marker for clinical evaluation.
Liu adds, "The study linked the coupling between the resting-state
global brain activity and cerebrospinal fluid flow to Alzheimer's
disease pathology. The finding highlights the potential role of
low-frequency (<0.1 Hz) resting-state neural and physiological
dynamics in the neurodegenerative diseases, presumably due to their
sleep-dependent driving of cerebrospinal fluid flow to wash out brain
toxins. Future studies are warranted to fully understand the global
brain activity and associated physiological modulations and their role
in glymphatic clearance and neurodegenerative diseases."
F, Chen J, Belkin-Rosen A, Gu Y, Luo L, Buxton OM, et al. (2021)
Reduced coupling between cerebrospinal fluid flow and global brain
activity is linked to Alzheimer disease-related pathology.PLoS Biol19(6): e3001233.doi.org/10.1371/journal.pbio.3001233