Cognitive Activities Protect Against Alzheimer's -- Social And Physical Activities Not Enough

Main Category: Alzheimer's / Dementia
Also Included In: Neurology / Neuroscience;  Biology / Biochemistry;  Seniors / Aging
Article Date: 13 Sep 2007 - 1:00 PDT

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New research now shows for the first time that, of all lifelong activities, only a high level of mental or cognitive activity protects against the devastating memory loss of Alzheimer's disease. High levels of social or physical activity are not enough.

Byrd Institute researchers raised Alzheimer's mice from young adulthood through old age in one of four housing environments -- high social activity, high physical activity, high cognitive activity, or a single-housing control environment. When the researchers tested the mice in a battery of memory tasks in old age, only the mice given a lifelong high level of cognitive activity were protected against memory impairment. In fact, these "high cognitive activity" mice performed as well as normal mice that do not develop Alzheimer's disease. In sharp contrast, the Alzheimer's mice raised in one of the other three environments performed poorly in multiple memory tasks.

Not only was memory protected in Alzheimer's mice by a high level of cognitive activity, but brain levels of the abnormal protein beta-amyloid were substantially reduced. This protein, thought to be key for Alzheimer's development, remained at soaring levels in the brains of Alzheimer's mice raised in social or physical activity environments. Moreover, the researchers found that only the Alzheimer's mice raised with high cognitive activity had an increase in connections between brain cells. Alzheimer's mice raised in one of the other three housing environments had much fewer connections between their brain cells.

The new study is published in the Neurobiology of Learning and Memory Journal.

"Our results call into question the earlier human studies suggesting social or physical activity provides protection against Alzheimer's," said Dr. Gary Arendash, the lead researcher on the study.

"Alzheimer's begins in the brain several decades before any symptoms´ show up," said Dr. Arendash. "That means adults in their forties and fifties need to make lifestyle choices now to decrease their risk of getting Alzheimer's disease later."

The Byrd Alzheimer's Institute
http://www.byrdinstitute.org