A novel model of human brain aging developed by a UCLA neuroscientist identifies midlife breakdown of myelin, a fatty insulation coating the brain's internal wiring, as a possible key to the onset of Alzheimer's disease later in life.
Detailed in the January edition of the peer-reviewed journal Neurobiology of Aging, the model presents opportunities to explore how lifestyle changes, hormone replacement therapy, higher education or treatment with common medications in middle age might help brains remain healthy longer.
"This model embraces the human brain as a high-speed Internet rather than a computer. The quality of the Internet's connections is the key to its speed, fidelity and overall capability," said Dr. George Bartzokis, the author and visiting professor of neurology at UCLA's David Geffen School of Medicine. He also is director of the UCLA Memory Disorders and Alzheimer's Disease Clinic and Clinical Core director of the UCLA Alzheimer's Disease Research Center.
"Close analysis of brain tissue and MRIs clearly shows that the brain's wiring develops until middle age and then begins to decline as the breakdown of myelin triggers a destructive domino affect. Our time at the peak is short indeed," Bartzokis said. "The challenge for science and medicine is to figure out how to extend the brain's peak performance so that our minds function as long as our bodies."
The journal also published six commentaries on the model written by investigators from around the world, as well as a response by Bartzokis. The response expands on his findings to discuss the role myelin plays in overall brain function as well as its dysfunction in many other neuropsychiatric disorders that occur over the human lifespan.
Myelin is a sheet of lipid, or fat, with very high cholesterol content -- the highest of any brain tissue. The high cholesterol content allow
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