Of Mice and
Men...Exercise and mental stimulation both
boost mouse memory late in life
Newswise — Physical
exercise is known to be good for the aging
brain, but what about mental stimulation? Does
enrichment that helps older people work well for
the young and middle aged, or do they need
something else? A report in the August issue of
Behavioral Neuroscience tells how, in an
animal experiment, older adults appear to
benefit from either or both mental and physical
enrichment. For the young and middle-aged,
exercise is key.
Behavioral Neuroscience
is published by the American Psychological
Association (APA).
At Yale University,
neuroscientists randomly assigned 160 female
mice who were young, middle-aged and old adults
(about 3, 15, or 21 months old) to either an
experimental (treatment) condition or a control
group. Treatment conditions included cages where
mice could exercise on running wheels, cages
where they could play with toys, or cages with
both for complex enrichment. The control mice
cages were unadorned. All groups lived with
their conditions around the clock for four weeks
prior to the start of memory testing and then
during testing.
After the initial four
weeks of treatment, researchers tested the
animals’ ability to navigate a spatial water
maze, a common test of learning and memory.
Spatial memory is supported in part by the
hippocampus, a brain region among the first to
be affected both by normal aging and Alzheimer's
disease. Thus, spatial memory is a good
indicator of hippocampal health in both mice and
humans.
For all of the experimental
mice, spatial memory worsened with age. However,
the various treatments differently affected the
different age groups:
Exercise alone
significantly improved the spatial memory of
the young.
Both exercise alone and complex enrichment,
but not cognitive stimulation alone,
significantly improved memory among the
middle aged.For old mice, all enrichments
(alone or combined) significantly improved
performance.
The results suggest that as
we get old and maybe less able to exercise,
cognitive stimulation can help to compensate. If
the trend holds, write the authors, “These data
may suggest that enrichment initiated at any age
can significantly improve memory function. And
exercise plus mental challenge in middle age –
when many people start to notice subtle memory
changes – may offer the strongest, most
widespread benefits for memory function.
The authors note that
exercise was central to memory reinforcement in
all age groups. Says lead author Karyn Frick,
PhD, “It is important for people of all ages to
do 20 to 30 minutes of aerobic exercise several
times a week. Keeping a healthy and active brain
may prevent memory decline in old age, but only
a longitudinal study that follows mice over time
could confirm this possibility.”
Article: “Single Enrichment
Variables Differentially Reduce Age-Related
Memory Decline in Female Mice,” Lauren L.
Harburger, MS, Chinonyere K. Nzerem, BA, and
Karyn M. Frick, PhD, Yale University;
Behavioral Neuroscience, Vol. 121, No. 4.
(Full text of the article
is available from the APA Public Affairs Office
and at
http://www.apa.org/journals/releases/bne1214679.pdf
)
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