Alzheimer’s disease may damage the brain in two phases, according to new research published in Nature Neuroscience on Monday.
The first phase is slow and quiet, occurring before people experience symptoms. It damages a few types of vulnerable cells. The second stage includes faster and more destructive damage and results in buildup of plaques and tangles, resulting in memory problems and other well-known changes.
For the study, the investigators examined 84 people using sophisticated brain mapping tools developed by the NIH’s Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative.
“One of the challenges to diagnosing and treating Alzheimer’s is that much of the damage to the brain happens well before symptoms occur. The ability to detect these early changes means that, for the first time, we can see what is happening to a person’s brain during the earliest periods of the disease,” Richard J. Hodes, MD, director of the National Institutes of Health (NIH) Institute on Aging, which funded the research, said in a statement. “The results fundamentally alter scientists’ understanding of how Alzheimer’s harms the brain and will guide the development of new treatments for this devastating disorder.”
Specifically, the researchers used genetic analysis tools to evaluate the cells of the middle temporal gyrus — a part of the brain responsible for language, memory and vision — the scientists saw that damage to inhibitory neurons happened during the early phase and may trigger the neural circuit problems that underlie the disease.
Because researchers have previously mapped the middle temporal gyrus from control donors, the team was able to compare that data with that of the people who had Alzheimer’s, forming a genetic and cellular timeline of what happens over the course of the disease.
“This research demonstrates how powerful new technologies provided by the NIH’s BRAIN Initiative are changing the way we understand diseases like Alzheimer’s. With these tools, scientists were able to detect the earliest cellular changes to the brain to create a more complete picture of what happens over the entire course of the disease,” John Ngai, PhD, director of The BRAIN Initiative, said in the statement. “The new knowledge provided by this study may help scientists and drug developers around the world develop diagnostics and treatments targeted to specific stages of Alzheimer’s and other dementias.”
