Alzheimer’s and aging change brain communication along different axes
Alzheimer’s disease and normal aging are associated with different patterns of communication across the brain, a new observational study finds. Researchers identified distinct connectivity axes in two independent groups, including changes linked to Alzheimer pathology before cognitive symptoms. The findings sharpen the biological distinction between aging and disease at group level; they do not yet establish an individual diagnostic or prediction test.
Science··Midday
Normal aging and Alzheimer’s follow different patterns
A brain-imaging study led by Lund University distinguished changes associated with normal aging from those associated with Alzheimer’s disease. More than a thousand people were included in the investigation. Both processes affect communication between brain regions, but the changes follow different patterns across the brain. Functional connections are organized differently as age advances and as disease pathology accumulates, allowing researchers to separate these brain-wide patterns.[1], [2]
Disease-linked changes appear before cognitive symptoms
The Alzheimer-related pattern was present in participants who remained cognitively unimpaired. Changes associated with early pathology therefore appeared before overt cognitive symptoms. In the direct paper, the disease-related changes follow a sensory–association axis, while aging follows a representation–executive axis. These are different large-scale pathways of brain communication. The findings concern coordinated patterns across regions, rather than treating each stronger or weaker connection as an isolated change.[1]
Group-level findings leave individual prediction open
The investigation was observational, with results examined in two independent cohorts. It did not test a treatment intended to change connectivity. The authors discuss whether early increases in connectivity reflect compensation or strain; the observations do not causally distinguish those explanations. The pattern associated with Alzheimer’s disease was distinguishable from normal aging at group level. Using a person’s scan to diagnose disease or predict future cognitive decline still requires individual clinical validation.[1]
Related columns
For more information on this topic, you can read the related columns.
