‘Blue spot’ in the brain aids in early detection of Alzheimer’s

A miniscule area in the brain can help to identify an increased risk of Alzheimer’s disease at a very early stage. The locus coeruleus (LC), or blue spot, is hidden deep in the brainstem and can only be detected with advanced MRI equipment. Heidi Jacobs (Maastricht University/Harvard Medical School) used MRI scans to show that the tau protein can begin to spread in the LC three decades before the first disease symptoms are visible. Scientists have long suspected that this tau protein plays an important role in the development of Alzheimer’s. Jacobs and her team recently published their findings in Science Translational Medicine.

locus coeruleus

Tau protein

Many researchers believe Alzheimer’s disease is caused by the amyloid protein. But the tau protein, too, appears to play a critical role. Tau forms harmful protein tangles in the brain cells of people with Alzheimer’s. Jacobs’ research shows that the development of these protein tangles is associated with changes in the blue spot in the brain. She was able to draw the link between the accumulation of tau in the LC and accelerated memory deterioration.

“The LC is tiny, so it’s difficult to map in living people,” Jacobs explains. “In Maastricht we studied this spot for the first time using new, ultra-strong MRI scanners. We shared that knowledge with Harvard Medical School, where the MRI scans were coupled with PET scans to visualise the tau protein in 174 people who have been followed in the US over the course of 10 years. We were able to show that changes in the LC in young adulthood are associated with tau-protein accumulations and memory problems typical of Alzheimer’s disease. Our findings also demonstrate that these early changes in the LC are not a normal part of ageing, but may actually signal the development of Alzheimer’s.”

Early stage

Alzheimer’s disease is the most common form of dementia. In the Netherlands, almost 300,000 people live with dementia, a number expected to exceed half a million by 2040. At present, no drug is available that cures dementia. But if an increased risk of Alzheimer’s can be detected at a very early stage, a healthier lifestyle could in turn reduce an individual’s risk of developing dementia. “The LC plays an important role in sleep, stress, emotions and memory,” Jacobs says. “For that reason, and because this spot is affected by the tau protein so early, MRI images of it can help to identify people at increased risk of Alzheimer’s disease. In the future, MRI measurements of the LC may provide clues for new treatments that slow the development of Alzheimer’s.”