Cerebrum Winter 2022

The default network in healthy adults is shown in blue, and the regions with amyloid plaque in Alzheimer’s disease is shown in red. They are overlaid on top of a histological view of plaques in postmortem tissue from a patient with Alzheimer’s. Of historical significance, the data included are the original data that illustrated the default network at rest in people scanned with PET Neuroimaging.

devastating. Since the higher order circuits that people use to remember are so adversely affected, we are seeing neurodegeneration in the pathways used for higher order, internal thought. When we pointed out that the default network might be vulnerable in Alzheimer’s disease, the immediate question became: ‘Well, then how do you change it? Can meditation, exercise, or diet change it? If we use our networks less for higher order thought, might this delay the accumulation or prevent the spread of amyloid? My hunch is no.

Can you change your default mode, or maybe train it? BUCKNER: The short answer is I don’t know. But this clinically relevant question drew my attention when we began studying how the default network is different in older individuals, including those with dementia. An observation is that amyloid, the protein that pathologically builds up in Alzheimer’s disease, deposits preferentially in the default network, which caught our attention in multiple ways. By better understanding these networks, it might help us to understand why Alzheimer’s disease is so



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