WASHINGTON, Aug. 24 (Xinhuanet) -- The parts of brain used to muse or daydream are the same where some aged people develop Alzheimer's disease, showed a US study published Wednesday.

    The study, which appears in The Journal of Neuroscience, suggests that the normal brain activity of daydreaming could trigger a life-long process that ends in Alzheimer's disease in some people.

    It found the evidence of Alzheimer's disease mostly appear in the brain's "default state" areas that are involved in musing or daydreaming.

    "We appear to use memory systems often in our default states. This may help us to plan and solve problems. Maybe it helps us be creative. But it may also have metabolic consequences," said lead author Randy Buckner, a Howard Hughes Medical Institute investigator at Washington University in St. Louis.

    "It may be the normal cognitive function of the brain that leads to Alzheimer's later in life. This was not a relationship wehad even considered," he said.

    Further study is needed to look better into the possible relationship, and the current result does not suggest that daydreaming is dangerous.

    The study involved 764 volunteers, including Alzheimer's patients, older people in the early stage of dementia, and healthypeople.

    Buckner and other researchers used five different imaging techniques to trace the brain activity of the participants. The techniques included positron emission tomography (PET) and magnetic resonance imaging (MRI).

    Alzheimer's is marked by the plaques and tangles formed from two proteins called beta-amyloid and tau, and the death of healthybrain cells. The degenerative brain disease leads to the loss of memory, learning ability and language. It affects 4.5 million people in the United States. Enditem