MONDAY, July 12, 2004 (HealthDayNews) -- Neural connections that form late in a person's brain are the first to degenerate, according to an article in the current issue of the Neurobiology of Aging.
UCLA researchers made the discovery while using magnetic resonance imaging (MRI) to examine the myelin sheaths that insulate the brain's wiring. Myelin is a high-cholesterol sheet of fat that speeds messages through the brain by insulating neural connections.
They found the myelin in the splenium -- a part of the brain where neural connections important to vision develop early -- degenerates at a slower rate than the myelin in the genu, a section of the brain that develops later and contains connections important to decision-making, memory, impulse control and other higher functions.
The findings support the hypothesis that Alzheimer's disease results from myelin breakdown, the researchers said.
"Myelin and the cells that produce it are the most vulnerable component of our brain -- the human brain's Achilles heel," lead author Dr. George Bartzokis said in a prepared statement. "Now that we can measure how brain aging proceeds in vulnerable regions, we can measure what treatments will slow aging down and thus begin in earnest to look at preventing Alzheimer's disease."
The Myelin Repair Foundation has more about myelin.