Alzheimer's Club

"Alzheimer's disease may be due to abnormalities in the regions of the brain that operate the "default state", a term used to describe the cognitive state people defer to when musing, daydreaming, or thinking to themselves, according to new research. Researchers from Howard Hughes Medical Institute (HHMI) 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.

"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," said the lead author of the study, Randy Buckner, a HHMI investigator at Washington University in St. Louis. "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. This is quite a remarkable convergence that we did not expect."

Buckner says the new findings are important because they could help scientists and clinicians identify and understand the beginnings of what is probably a cascade of events that ultimately leads to Alzheimer's. Researcher Randy Buckner: "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."The most common form of dementia among older people, Alzheimer's is characterized outwardly by the erosion of language, thought and memory. Within the brains of people with Alzheimer's disease, abnormal clumps of plaque and tangled bundles of fibers form and characterize the physical manifestation of the disease, which may affect as many as 4.5 million Americans. The causes of the disease are unknown.

The availability of powerful imaging techniques and the ability to merge different sets of imaging data through new bioinformatics and statistical methods enabled Buckner and his team 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 remarkable correlation, said Buckner, suggests that dementia may be a consequence of the everyday function of the brain. The study is published in the current issue of the Journal of Neuroscience"

Source: Nick Gibbens. Daydreaming linked to Alzheimer's. www.999today.com (30 August 2005) [FullText]