"It may be the normal cognitive function of the brain that leads to Alzheimer's later in life. This was not a relationship we had even considered," said Randy Buckner, a Howard Hughes Medical Institute investigator at Washington University in St. Louis who led the study.
For their study, Buckner and colleagues used five different imaging techniques to study the brain activity of 764 volunteers, including those with Alzheimer's, those close to developing dementia, and healthy people.
When people are concentrating on a task such as solving problems, the brain uses one set of regions, but during down time it switches to a default mode.
"The regions of the brain we tend to use in our default state when we are young are very similar to the regions where plaques form in older people with Alzheimer's disease," Buckner said.
As it stands, Alzheimer's has no cure and there are no long-lasting treatments for the brain-destroying illness, which affects an estimated 4.5 million Americans.
