A new review of scientific studies suggests a small area of the brain may be the first place affected by late onset Alzheimer’s disease. The region, known as the locus coeruleus, may also be important for maintaining cognitive function in later life.
Investigators explain that stimulation of this brain region through mental games or other cognitively engaging activities may help to maintain cognitive reserve.
The locus coeruleus is a small, bluish part of the brainstem that releases norepinephrine, a neurotransmitter involved for regulating heart rate, attention, memory, and cognition.
Its cells, or neurons, send branch-like axons throughout much of the brain and help regulate blood vessel activity.
This high interconnectedness may make it more susceptible to the effects of toxins and infections compared to other brain regions, said Dr. Mara Mather, professor of gerontology and psychology at the University of Southern California.
Her research suggests the locus coeruleus is the first brain region to show tau pathology — the slow-spreading tangles of protein that can later become telltale signs of Alzheimer’s disease.
Although not everyone will contract Alzheimer’s, autopsy results indicate that most people have some initial indications of tau pathology in the locus coeruleus by early adulthood, explains Mather.
The norepinephrine released from the locus coeruleus may contribute to preventing Alzheimer’s symptoms. Studies conducted with rats and mice have shown that norepinephrine helps protect neurons from factors that kill the cells and accelerate Alzheimer’s disease, such as inflammation and excessive stimulation from other neurotransmitters.
Norepinephrine is released when someone is engaged in or mentally challenged by an activity, whether it’s solving problems in the workplace, completing a word puzzle, or playing a difficult piece of music.
“Education and engaging careers produce late-life ‘cognitive reserve,’ or effective brain performance, despite encroaching pathology,” Mather said.
“Activation of the locus coeruleus-norepinephrine system by novelty and mental challenge throughout one’s life may contribute to cognitive reserve.”