April 10, 2005 — WASHINGTON — College seems
to pay off well into retirement. A new study from the University of
Toronto sheds light on why higher education seems to buffer people from
cognitive declines as they age. Brain imaging showed that in older
adults taking memory tests, more years of education were associated
with more active frontal lobes – the opposite of what happened in young
adults. It appears possible that education strengthens the ability to
"call in the reserves" of mental prowess found in that part of the
brain.
A full report appears in the March issue of Neuropsychology, which is published by the American Psychological Association (APA).
A team of psychologists led by Mellanie Springer, MSc, chose a
memory task because even normal aging brings some memory loss. They
were intrigued by how highly educated patients with Alzheimer’s disease
appear to be better able than less educated patients to compensate for
brain pathology, which suggested that education somehow protects
cognition.
To understand the mechanism, the researchers studied the
relationship between education and brain activity in two different age
groups: 14 adults of ages 18 to 30, with 11 to 20 years of education,
and 19 adults of age 65 and up, with eight to 21 years of education.
Springer and her colleagues ran each participant through several memory
tests while scanning his or her brain with functional magnetic
resonance imaging (MRI). The resulting images showed Springer and her
colleagues which neural networks became active when participants tapped
into memory. The psychologists then correlated brain activity for each
member of the two groups with their corresponding years of education.
Relative to education, younger and older adults had opposite
patterns of activity in the frontal lobes (behind the forehead) and
medial temporal lobes (on the sides). In young adults performing the
memory tasks, more education was associated with less use of the
frontal lobes and more use of the temporal lobes. For the older adults
doing the same tasks, more education was associated with less use of
the temporal lobes and more use of the frontal lobes.
The finding suggests that older adults — especially the highly
educated — use the frontal cortex as an alternative network to aid
cognition. Says co-author Cheryl Grady, PhD, "Many studies have now
shown that frontal activity is greater in old adults, compared to
young; our work suggests that this effect is related to the educational
level in the older participants. The higher the education, the more
likely the older adult is to recruit frontal regions, resulting in a
better memory performance." Grady is assistant director of the Rotman
Research Institute In Toronto and holds a Canada Research Chair in
Neurocognitive Aging.
Education appears to enable older people to more effectively "call
up the reserves." Highly educated older adults might be better able to
enlist the frontal lobes into working for them as a type of cognitive
reserve or alternative network. Grady cites evidence that when older
adults tap their frontal lobes, that activity engages the medial
temporal regions less than it does in younger adults. She speculates
that "if the medial temporal lobes can’t be recruited properly, the
frontal lobes have to help out." Grady further thinks that the frontal
lobes’ compensatory role supports cognition generally.
Researchers hope to further understand how mental exercise
strengthens mental muscles, so to speak, in old age. Animal brains
respond to more complex environments by growing more neural
connections; perhaps, says Grady, "more education while the brain is
still developing — up to age 30 it is still maturing – causes more
connections between brain regions to form. When some of these are lost
with age, there are still enough left, a type of redundancy in the
system."
She adds that highly educated people keep more active physically and
mentally as they age, which also has a beneficial effect on cognition.
Source : American Psychological Association