The association between Amyloid-beta and tau proteins and Alzheimer’s is well known. The harmful buildup of these proteins causes cognitive decline in people with the disease. However, we don’t fully understand how this happens.
Scientists at The Neuro and Sylvia Villeneuve at the Douglas Research Centre offer significant information. In the study, which involved 104 people with a family history of Alzheimer’s, they scanned the participants’ brains using a combination of positron emission tomography (PET).
They wanted to detect the presence and location of the proteins and magnetoencephalography (MEG) to record brain activity in these regions.
The scientists looked at two brain scans and found that areas with more amyloid-beta showed increased brain activity, with faster brain waves being more common. Brain activity slowed down more in people with amyloid-beta and tau as the disease worsened.
Cognitive tests showed that those with slowing brain activity also had more significant problems with attention and memory.
The findings suggest that the interaction between amyloid-beta and tau changes brain activity before apparent memory problems appear. In a follow-up study, scientists plan to scan the same participants again over time to see if the buildup of these proteins causes more brain slowing and if this can predict how their thinking skills will change.
Jonathan Gallego Rudolf, a Ph.D. candidate in Baillet and Villeneuve’s labs, said, “Our study provides direct evidence in humans for the hypothesized shift in neurophysiological activity, from neural hyper- to hypo-activity, and its association with longitudinal cognitive decline. These results parallel findings from animal and computational models and contribute to the advancement of our understanding of the pathological mechanisms underlying the preclinical stage of Alzheimer’s disease.”
Journal Reference:
- Gallego-Rudolf, J., Wiesman, A.I., Pichet Binette, A. et al. Synergistic association of Aβ and tau pathology with cortical neurophysiology and cognitive decline in asymptomatic older adults. Nat Neurosci (2024). DOI: 10.1038/s41593-024-01763-8
