When most people think of dementia, including Alzheimer's disease, they probably think of memory loss first. But dementia also changes the way a person behaves, whether it makes them quick to get angry or distressed, causes them to become depressed, anxious or apathetic, or even changes their whole personality. Over time, these behavioral changes can disrupt their lives as much as losing their ability to think or remember clearly.
Now, a team of University of Michigan researchers reports new clues about what might be happening in the brains of people experiencing even the earliest signs of dementia-related behavior changes. Using two types of advanced medical imaging to study the brains of 128 people in the early stages of dementia, they show links between one of the brain's most crucial communication networks, a protein called tau, and the level of behavioral symptoms a person has. This goes beyond the role of tau that scientists have already known about in people with more advanced dementia: causing tangled nerve fibers in brain regions involved in thinking and memory.
The new study suggests that tau disrupts the integrity of the brain's salience network. This highway of connections between specific brain regions is key to our ability to understand and decide how to react to things that are happening around us. It also helps us process our own thoughts and emotions.
The researchers showed that the more a person's salience network had been disrupted in the presence of tau, t.