When people think of dementia, especially Alzheimer’s disease, memory loss is often the first thing that comes to mind. But dementia also changes a person’s behavior. These changes include agitation, anxiety, sadness, or apathy, and may even change their whole personality.
These behavioral changes can be as devastating as the loss of cognition or memory. Now, University of Michigan researchers have uncovered new clues about why these changes happen, even in early-stage dementia.
Using advanced medical imaging, the research team studied the brains of 128 people with early-stage dementia. They discovered a tie between the tau protein, the salience network of the brain, and the level of behavioral symptoms experienced by a person.
Tau has been infamous for causing tangles of nerve fibers in the brain, especially those areas responsible for thinking and memory. However, this research opened a new understanding that tau causes an assault on the salience network of the brain. The salience network is a usual way that brain regions communicate with each other to help us understand. And react to events around us, also processing our own thoughts and emotions.
They found that as tau disrupts the salience network, the associated behavioral changes tend to become more severe. Although this study showed only a strong association of tau, network disruption. And symptoms for one behavior, it does open the door to further research.
They also suggest that studies of other populations and across time could explain changes in the salience network. And how those changes relate to tau buildup and behavioral changes. They also are interested in testing the idea that, in people with early-stage dementia, “stimulating the salience network with a mild electric current or a magnetic field could delay this behavioral decline.”
The lead author, Dr. Alexandru D. Iordan, and his team mapped the brains using fMRI; they also used PET scans to look for tau. And another protein linked to Alzheimer’s disease: beta-amyloid.
Interestingly, they found that the salience network was the only one of three major brain networks that correlated with tau presence and behavioral symptoms. Surprisingly, amyloid alone did not seem to affect the salience network.
Dr. Iordan says the study provides new insight into early signs of dementia and may point toward future intervention. He says, that comprehending the role of the salience network might give a clue to treatments that could slow the course of dementia-related behavior changes.
ANI
