Scientists have found differences between brain aging and Alzheimer's disease

Normal aging and Alzheimer's disease change the interaction between brain regions in different ways. A study by scientists from Lund University has shown that changes in brain connectivity characteristic of the disease can occur even before the onset of cognitive symptoms. How these processes differ from age—related changes is described in the Izvestia article.

Aging and Alzheimer's disease are two different patterns.

The researchers studied brain imaging data from more than 1,000 people to compare changes in functional connectivity with normal aging and the accumulation of pathological changes associated with Alzheimer's disease. Functional connectivity refers to how different areas of the brain interact with each other. The work was published in the journal Nature Neuroscience.

The researchers found that the changes were not limited to individual pairs of brain regions. They simultaneously affected several parts of it and formed consistent patterns. At the same time, the direction of changes in normal aging differed from that observed with the accumulation of Alzheimer's pathology.

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The first differences appear even before the symptoms

The authors found a pattern of changes characteristic of the disease, even in people with low levels of Alzheimer's disease, who did not have cognitive impairments.

This indicates that changes in functional connectivity may occur in the early stages of the disease, even before noticeable cognitive symptoms appear.

Memory and sensory areas — the changes went in different directions

With the accumulation of Alzheimer's pathology, communication between higher-order brain regions involved in functions such as memory became more similar. At the same time, the sensory and motor areas of the brain became more diverse in the nature of their communication.

With normal aging, a different pattern was observed. The areas associated with executive functions became more similar, while other areas, on the contrary, differed more strongly.

Thus, the researchers concluded that the effects of aging and Alzheimer's disease on functional connectivity cannot be considered simply as different degrees of the same process. They form various patterns of changes related to the organization of the brain.

Brain connectivity has been linked to cognitive functions.

In the study, the discovered pattern of functional connectivity was more strongly associated with cognitive functions than with the accumulation of two proteins associated with Alzheimer's disease, amyloid beta and tau, in people with cognitive impairments.

The researchers suggest that in the future, such changes in communication between brain regions may help identify disease-related changes even before there is a noticeable decrease in the volume of individual brain regions or cognitive symptoms appear. The authors also note that functional connectivity tracking could potentially be used to assess changes in brain function.

The group result has yet to be confirmed

The authors emphasize that the discovered patterns cannot yet be used to distinguish Alzheimer's disease from normal aging in a particular person. First, it is necessary to confirm the results on an individual level and check whether the identified patterns are capable of predicting subsequent cognitive decline.

According to the authors, before connectivity patterns can be used to distinguish between Alzheimer's disease and normal brain aging, the patterns found at the group level need to be confirmed using individual indicators and to find out whether they can predict subsequent cognitive decline.