A team of scientists from the University of Southern California has pinpointed a vulnerable region of the brain that is the first place to be affected by the late onset of Alzheimer's disease. This region, referred to as "ground zero," may be more important for the maintenance of cognitive function later in life than previously believed and could help in future treatments for the neurodegenerative disease.
The region in question is the locus coeruleus, a small, bluish-colored formation of the brainstem that releases the neurotransmitter norepinephrine, which is responsible for the regulation of heart rate, attention, memory and cognition. The axons of locus coeruleus neurons branch out to many areas of the brain in order to regulate blood vessel activity, and this high degree of interconnectedness could increase the structure's susceptibility to toxins and infections in comparison to other areas of the brain.
Supporting the above notion of the locus coeruleus's vulnerability is the fact that it is the first region in the brain to show the slow-spreading tangles of the tau protein that later become the signature signs of Alzheimer's disease. Even those who do not develop the disease show some initial signs of tau pathology in the locus coeruleus.
The team believes that the norepinephrine that is released from this brain structure could help in the prevention of Alzheimer's symptoms, with numerous rat and mouse studies evidencing its protective effects on neurons, shielding them from factors that lead to cell death and accelerate Alzheimer's disease, including inflammation and excessive neurotransmitter stimulation.
"Education and engaging careers produce late-life 'cognitive reserve,' or effective brain performance, despite encroaching pathology," Mara Mather, lead author of the study, 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."
The findings were published in the Feb. 16 issue of Trends in Cognitive Sciences.