Exercise can change how
crucial portions of our brain communicate as we age, improving aspects of
thinking and remembering, according to a fascinating new study of aging brains
and aerobic workouts. The study, which involved older African Americans, finds
that unconnected portions of the brain’s memory center start interacting in
complex and healthier new ways after regular exercise, sharpening memory
function.
اضافة اعلان
The findings expand our
understanding of how moving molds thinking and also underscore the importance
of staying active, whatever our age.
The idea that physical
activity improves brain health is well established. Experiments involving
animals and people show exercise increases neurons in the hippocampus, which is
essential for memory creation and storage, while also improving thinking
skills. In older people, regular physical activity helps slow the usual loss of
brain volume, which may help to prevent age-related memory loss and possibly
lower the risk of dementia.
There have been hints, too,
that exercise can alter how far-flung parts of the brain talk among themselves.
In a 2016 magnetic resonance imaging (MRI) study, for instance, researchers
found that disparate parts of the brain light up at the same time among
collegiate runners but less so among sedentary students. This paired brain
activity is believed to be a form of communication, allowing parts of the brain
to work together and improve thinking skills, despite not sharing a physical
connection. In the runners, the synchronized portions related to attention,
decision-making and working memory, suggesting that running and fitness might
have contributed to keener minds.
But those students were
young and healthy, facing scant imminent threat of memory loss. Little was
known about whether and how exercise might alter the communications systems of creakier,
older brains and what effects, if any, the rewiring would have on thinking.
So, for the new study, which
was published in January in Neurobiology of Learning and Memory, Mark Gluck, a
professor of neuroscience at Rutgers, the state university of New Jersey, and
his colleagues decided to see what happened inside the brains and minds of much
older people if they began to work out.
In particular, he wondered
about their medial temporal lobes. This portion of the brain contains the
hippocampus and is the core of our memory center. Unfortunately, its inner
workings often begin to sputter with age, leading to declines in thinking and
memory. But Gluck suspected that exercise might alter that trajectory.
Helpfully, as the director
of the Aging & Brain Health Alliance at Rutgers, he already was leading an
ongoing exercise experiment. Working with local churches and community centers,
he and his collaborators previously had recruited sedentary, older African
American men and women from the Newark, New Jersey, area. The volunteers, most
of them in their 60s, visited Gluck’s lab for checks of their health and
fitness, along with cognitive testing. A few also agreed to have their brain
activity scanned.
Some then started working
out, while others opted to be a sedentary control group. All shared similar
fitness and memory function at the start. The exercise group attended hourlong
aerobic dance classes twice a week at a church or community center for 20 weeks.
Now, Gluck and his research
associate Neha Sinha, along with other colleagues, invited 34 of those
volunteers who had completed an earlier brain scan to return for another.
Seventeen of them had been exercising in the meantime; the rest had not. The
groups also repeated the cognitive tests.
Then the scientists started
comparing and quickly noticed subtle differences in how the exercisers’ brains
operated. Their scans showed more synchronized activity throughout their medial
temporal lobes than among the sedentary group, and this activity was more
dynamic. Portions of the exercisers’ lobes would light up together and then,
within seconds, realign and light up with other sections of the lobe. Such
promiscuous synchronizing indicates a kind of youthful flexibility in the
brain, Gluck says, as if the circuits were smoothly trading dance partners at a
ball. The exercisers’ brains would “flexibly rearrange their connections,” he
says, in a way that the sedentary group’s brains could not.
Just as important, those
changes played out in people’s thinking and memories. The exercisers performed
better than before on a test of their ability to learn and retain information
and apply it logically in new situations. This kind of agile thinking involves
the medial temporal lobe, Gluck says, and tends to decline with age. But the
older exercisers scored higher than at the start, and those whose brains
displayed the most new interconnections now outperformed the rest.
This study involved older
African Americans, though, a group that is underrepresented in health research
but may not be representative of all aging people. Still, even with that
caveat, “it seems that neural flexibility” gained by exercising a few times a
week “leads directly to memory flexibility,” Gluck says.
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