Summary: University of Michigan researchers used fMRI to show that early-stage disruptions in the brain’s salience network, caused by tau protein buildup, are linked to dementia-related behavioral changes, offering a potential target for intervention like brain stimulation.
Key Takeaways
- University of Michigan researchers found that disruptions in the brain’s salience network, caused by tau protein buildup, are linked to behavioral changes in early-stage dementia.
- The study revealed that the severity of behavioral symptoms is tied to the extent of disruption in the salience network, rather than a direct relationship with tau pathology.
- These findings provide a potential target for interventions, such as brain stimulation, to slow or alter the progression of behavioral symptoms in dementia.
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University of Michigan researchers used advanced brain imaging, including functional MRI (fMRI), to explore the link between dementia-related behavioral changes and disruptions in the brain’s communication networks. Studying 128 individuals in early stages of dementia, they found that the salience network—a key system that helps process emotions and reactions—was disrupted by the buildup of the tau protein, which is strongly linked to behavioral symptoms.
Lead author Alexandru Iordan, PhD, explains, “What we see is that the presence of tau pathology relates to behavioral symptoms not in a direct relationship, but rather through dysfunction of a specific network in the brain—the salience network. The more affected this network is, the more severe the behavioral symptoms.”
Salience Network Key to Dementia Behavior
Tau’s role in advanced dementia is known to cause nerve fiber tangles in memory-related brain areas, but this study shows that even early-stage disruptions in the salience network are tied to behavioral changes. Iordan notes, “This is the first study that links the biomarker status of an individual with the dysfunction of this network, and behavioral symptoms, in people on the Alzheimer’s disease spectrum.”
The team combined fMRI findings with neuropsychological tests and PET scans, showing that the more disrupted a person’s salience network was in the presence of tau, the greater their behavioral symptoms. These findings offer a potential target for intervention, such as brain stimulation to slow or alter the progression of behavioral symptoms in dementia.
“Our findings provide us with a functional target for potential intervention,” says Iordan. The team is eager to see results from an ongoing study, led by Benjamin Hampstead, Ph.D., which evaluates brain stimulation using weak electrical currents to influence these networks.
