The parts of the brain that young, healthy people use when daydreaming are the same areas that fail in people who have Alzheimer's disease, researchers reported on Wednesday in a study that may someday help in preventing or diagnosing the disease.
The study, published in the Journal of Neuroscience, suggests that the way people use their brains could actually lead to Alzheimer's disease.
"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.
The relationships are not clear and do not yet suggest that daydreaming is dangerous, but further study may shed light on the relationship, the study said.
The study found that Alzheimer's mostly affects the brain's "default state" regions - used when musing or daydreaming.
"We appear to use memory systems often in our default states," Buckner said in a statement. "This may help us to plan and solve problems. Maybe it helps us be creative. But it may also have metabolic consequences," reports Reuters.
The scientists say this finding could prove useful diagnostically - a way to identify the disease early, even before symptoms appear.
"You have to get to this pathology before it has its biggest effect," said William Klunk, an associate professor of psychiatry at the University of Pittsburgh and a co-investigator in the current study. Klunk developed an imaging tool that tracks amyloid plaque deposited in the brains of living Alzheimer's patients.
The next step will be to see whether the sticky amyloid-filled plaques are dependent on the brain's metabolism. If so, there could be novel ways to attack the disease.
The latest thinking among Alzheimer's scientists is that the underpinnings of the disease may be decades in the making. About a decade ago, David Snowdon of the University of Kentucky Medical Center published what has become a classic study of health and aging. He followed 678 nuns, ranging in age from 75 to 107, and analyzed journal entries and essays written when they joined the order as young women. He identified an association between the writing and the risk for Alzheimer's far into the future. The richer the detail in the essays, the less likely the writers were to develop Alzheimer's, informs Newsday.