Researchers have found that the areas of the brain that young, healthy people use when daydreaming are the same areas that fail in people who have Alzheimer's disease.
Howard Hughes Medical Institute researchers used five different medical imaging techniques to study the brain activity of 764 people, including those with Alzheimer's disease, those on the brink of dementia, and healthy individuals. They have developed a hypothesis that Alzheimer's disease may be due to abnormalities of the brain regions that operate the "default state"-the term used to define the state people are in when musing, daydreaming, or thinking to themselves. Those regions are similar to the regions where plaques form in older people with the disease.
Writing in the Journal of Neuroscience, the researchers state that "the default activity patterns of the brain may, over many years, augment a metabolic- or activity-dependent cascade that participates in Alzheimer's disease pathology." The new findings could help scientists and clinicians identify and understand the beginnings of what is probably a series of events that ultimately leads to Alzheimer's.
The availability of powerful imaging techniques and the ability to merge different sets of imaging data through new bioinformatics and statistical methods enabled researchers to construct a picture of Alzheimer's from molecular changes to the structural and functional manifestations of the disease. In the process, the team unexpectedly observed that the regions of the brain that light up when we slip into comfortable patterns of thought are the same as those that, later in life, exhibit the disabling clumps of plaque characteristic of Alzheimer's, a disease that most frequently manifests itself after age 60. That correlation suggests that dementia may be a consequence of the everyday function of the brain.