[Paleopsych] Newsday: Idle brain invites dementia

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Idle brain invites dementia

Researchers say daydreaming may cause changes that lead to the onset of
Alzheimer's disease

    August 25, 2005

    Scientists have scanned the brains of young people when they are
    doing, well, nothing, and they found that a region active during this
    daydreaming state is the one hard-hit by the scourge of old age:
    "We never expected to see this," said Randy L. Buckner, a Howard
    Hughes Medical Institute investigator at Washington University in St.
    Louis. He said he suspects these activity patterns may, over decades
    of daily use, wear down the brain, sparking a chemical cascade that
    results in the disease's classic deposits and tangles that damage the
    The regions identified are active when people daydream or think to
    themselves, Buckner said. When these regions are damaged, an older
    person may not be able to access the thoughts to follow through on an
    action, or even make sense of a string of thoughts. The study appears
    this week in the Journal of Neuroscience.
    The scientists used a variety of brain-scanning devices in more than
    760 adults of all ages. Usually, scanning is done when volunteers
    carry out a particular mental task, such as remembering a list of
    words. This time, they were scanned without anything to do.
    What emerged on the images was what Buckner and his colleagues call
    the brain's "default" state. The brain remains in this state when it's
    not concentrating on a task like reading or talking. It's the place
    where the mind wanders. This default region lines up perfectly with
    the regions that are initially damaged in Alzheimer's.
    "It may be the normal cognitive function of the brain that leads to
    Alzheimer's later in life," Buckner said. He suspects the brain's
    metabolic activity slows over time in this region, making it
    vulnerable to mind-robbing symptoms.
    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.
    Others have confirmed these findings, including a study by Case
    Western Reserve University School of Medicine researchers. They
    recently published a study using high school records from the 1940s to
    identify nearly 400 graduates. They tracked their health status
    through adulthood into old age. A higher IQ in high school reduced the
    risk of Alzheimer's by about half.

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