Most people think of Alzheimer’s disease as an illness of aging. But in fact, the brain changes that characterize it begin much earlier – sometime around the third decade of life.
In the earliest of these changes, a tangled version of a protein called tau starts building up in a tiny region deep in the brain involved in sleep, attention and alertness, called the locus coeruleus. Tau later spreads to the rest of the brain.
Developing tau tangles doesn’t mean a person has Alzheimer’s disease – in fact, it happens to nearly everyone to varying degrees. But because these changes start in the locus coeruleus, some brain researchers – myself included – see this area as a canary in the coal mine for developing Alzheimer’s disease.
We are exploring whether stopping or slowing down tau tangles in this brain region, or otherwise maintaining its health, may be a way to interrupt how the disease ultimately unfolds and to prevent other aspects of cognitive aging.
Emerging research from my lab and others is investigating the idea that a therapy called vagus nerve stimulation, which is already widely used for other health conditions, could be one way of keeping the locus coeruleus functioning properly.
The locus coeruleus and Alzheimer’s disease
The locus coeruleus sits in the brain stem, the lowest part of the brain. Its name, “blue spot,” comes from a pigment called neuromelanin that its cells produce.
The locus coeruleus plays a crucial role in multiple aspects of basic human functioning. It makes virtually all of the brain’s norepinephrine, a chemical critical for sleep, alertness, focus, learning and even immune function. And it receives inputs from nerves originating throughout the brain and body – including from the vagus nerve, which carries information to and from the heart, lungs and other organs.
My research explores this brain region’s structure, how nerve cells pass messages within it and how it connects with other brain regions. I also investigate how those features change throughout life and affect thinking and memory.
Alzheimer’s disease destroys memory and thinking skills, but researchers don’t yet understand how or why.
Studies suggest that starting in middle age, nerve cells in the locus coeruleus may get damaged by tau buildup, and that damage may correlate with declines in memory. Tau buildup, cell death and loss of function in the locus coeruleus precedes and predicts Alzheimer’s diagnosis and symptoms.
This has led researchers to hypothesize that keeping the locus coeruleus healthy could be a way to protect the rest of the brain, too.
Vagus nerve stimulation and brain health
The vagus nerve carries information between the brain and organs in the chest and abdomen, such as the heart and intestines, helping the brain monitor and regulate many of the body’s essential organs. It is responsible for sending rest…
