First brain region affected by Alzheimer's disease identified

LOS ANGELES, Feb. 17 (UPI) -- Researchers found the part of the brain affected by Alzheimer's disease first, and think engaging in mentally challenging activities could help prevent its development.

The locus coeruleus was found by researchers at the University of Southern California to be susceptible to the disease first because of its job regulating blood vessel activity in the brain and interconnectedness to the entire organ.

Previous research has shown that both cognitive and physical activity can help slow or prevent the build-up of fats and proteins that disrupt brain and memory function in people with dementia-type diseases.

For the new study, published in the journal Trends in Cognitive Sciences, researchers reviewed previous studies on cognitive aging and the development of related diseases such as Alzheimer's.

They found the locus coeruleus, a small part of the brain that releases norepinephrine, a neurotransmitter responsible for regulating heart rate, attention, memory and cognition, is among the first parts of the brain affected by Alzheimer's disease. Part of the reason, they said, is its location and branch-like axons that extend through much of the brain, making it more susceptible to toxins and infections in other parts of the organ.

The researchers report that autopsy results show tau pathology, the spreading of proteins known to be a sign of Alzheimer's, can be found in early adulthood. Although tau pathology spreads slowly over most people's lifetimes as part of aging, only some end up with the disease.

Studies with rats and mice have shown norepinephrine can protect neurons from inflammation and excessive stimulation that contributes to Alzheimer's disease, leading them to suggest that increasing the amount of norepinephrine could help prevent the disease's causes.

"Education and engaging careers produce late-life 'cognitive reserve,' or effective brain performance, despite encroaching pathology," Mara Mather, a professor at the University of Southern California, said in a press release. "Activation of the locus coeruleus-norepinephrine system by novelty and mental challenge throughout one's life may contribute to cognitive reserve."