The
findings of a new study suggest that the protective effects of an active
cognitive lifestyle arise through multiple biological pathways.
For some time researchers have been aware of a link
between what we do with our brains and the long term risk for dementia. In
general, those who are more mentally active or maintain an active cognitive
lifestyle throughout their lives are at lower risk.
"The ideas of a 'brain reserve' or 'cognitive
reserve' have been suggested to explain this, but were basically a black box.
This research throws some light on what may be happening at the biological level,"
said Associate Professor Michael J. Valenzuela, a brain aging expert at the
Brain and Mind Research Institute, University of Sydney, Australia, who led
this new study.
Researchers used data from the Cognitive Function
and Ageing Study, a large population-based study in the United Kingdom that has
been following over 13,000 elderly individuals prospectively
since 1991.
At the time of this study, 329 brains had been
donated and were available for analysis. Brains were compared based on the
individual's dementia status at death (yes or no) and cognitive lifestyle
score, or CLS (low, middle, or high).
The three CLS groups did not differ among multiple
Alzheimer's disease (AD) neuropathology measures,
including plaques, neurofibrillary tangles, and atrophy. This
means that cognitive lifestyle seems to have no effect on the brain changes
typically seen in those with Alzheimer's disease.
However, an active cognitive lifestyle in men was
associated with less cerebrovascular
disease, in particular disease of the brain's microscopic blood vessels. An
active cognitive lifestyle in women was associated with greater brain weight.
In both men and women, high CLS was associated with greater neuronal density
and cortical thickness in the frontal lobe.
"These findings suggest that increased
engagement in stimulating activities are part of a lifestyle that is, overall,
more healthy," commented Dr. John Krystal, Editor of Biological
Psychiatry. "Rather than specifically protecting the health of
activated circuits, it seems that a more active lifestyle has general effects
on brain health reflected in greater neuronal density and preservation of the
blood supply to the brain."
"Overall, our research suggests that multiple
complex brain changes may be responsible for the 'use it or lose it'
effect," Valenzuela added.
With a globally aging society and the risk of
dementia increasing significantly with age, dementia-prevention strategies are
of rising importance. Understanding the mechanisms of cognitive enhancement
through research such as this can help support and inform the development of
effective strategies to enrich cognitive lifestyle and potentially reduce
dementia risk.
More
information: The article is "Multiple Biological
Pathways Link Cognitive Lifestyle to Protection from Dementia" by Michael
J. Valenzuela, Fiona E. Matthews, Carol Brayne, Paul Ince, Glenda Halliday,
Jillian J. Kril, Marshall A. Dalton, Kathryn Richardson, Gill Forster,
Perminder S. Sachdev, for the Medical Research Council Cognitive Function and
Ageing Study (doi:10.1016/j.biopsych.2011.07.036). The article appears in Biological
Psychiatry, Volume 71, Issue 9 (May 1, 2012).
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