Roads to resculpting
a variety of strategies have been shown to reverse the eye condition known as amblyopia in adult rats. scientists hope some of these
same approaches could work in human adults, reinstating a youthful, flexible state that allows for healing.
kept in complete darkness are able to regain
some sight during
through a shift of nerve
using a compound
abc to dissolve components of perineuronal
nets, which hold nerve
cells in place, improves
although it’s not clear
how it works, a short-term bout of severe
calorie-cutting seems to
reset the brain’s clock
and allow recovery from
an ssri used to treat
(brand name Prozac)
can reactivate adult
brain plasticity in
rodents, leading to a
full recovery of vision.
living in a place with
ample time for exercise,
toys and friends boosts
the brain’s malleability
these brain-training regimes have yet to
“We are continuously being exposed
to the environment, and those things
that impinge upon us are continuously
shaping our brains,” Davidson says.
So the question isn’t so much whether
something can change the brain, but
rather, how people can take charge of
the process for a desired outcome.
Studies by Levi and his collaborators
have found that a certain kind of vision
practice can actually help adults see better. Hours of difficult vision training, in
which people had to discern hazy lines,
for instance, improved vision in people with amblyopia, normal vision and
even normal age-related vision decline.
People could see sharper images, detect
contrasts better and even read small
rat image: basel101658/shutterstock; icons: t. dubÉ
Older people’s eyes still sent blurry
information to their brain, but the brains
were better equipped to handle it, Levi
and colleagues wrote in Scientific Reports .
Levi believes that the improvement
comes from a training-enhanced ability
to pay attention to relevant information
and ignore the blurred distractions.
There may be a more fun way. Data
from Bavelier support a counterintuitive
idea: Mindless video games actually
make the brain sharper. Action-packed
video games like Call of Duty 2 seem to
enhance people’s perception, and not just
in ways required to get a high score. “You
get benefits that ripple,” Bavelier says.
After logging hours at the games,
people were better at nimbly switching between two demanding jobs and
quickly determining whether a number
is even or odd. The results, reported in
May in Computers in Human Behavior,
suggest that this kind of brain training
reopens a window. “What really changes
is the ability to locate resources and
ignore distractions,” Bavelier says.
Flexibility too far
Efforts toward restoring plasticity hold
great promise, but only when targeted
to hit particular brain systems. If not,
the potential benefits come with some
strong caveats. “I’m very scared of taking
off the brakes,” Hensch says. “They’re
there for a reason.”
Myelin insulation on nerve cells, for
instance, is damaged in patients with
multiple sclerosis. That damage affects
the conduction of nerve impulses, leading
to the hallmark symptoms of the disease.
In Hensch’s lab, the mice genetically
engineered to lack lynx1 protein show
dementia-like damage in their brains
earlier than their normal counterparts.
“After nine months, you see holes in cor-
tex,” Hensch says. Parts of the brain that
are damaged earliest are the most mal-
leable throughout life. “Maybe the price
we pay for plasticity is the susceptibility
Brakes may also help the brain know
what not to learn. Extremely proficient
musicians have reported a rare condi-
tion in which neural pathways become
so shaped by playing music that the per-
formers’ brains fuse the control regions
for separate fingers, and the ability to
cleanly pluck a single string is lost.
s d. maurer and t. hensch. “amblyopia:
background to the special issue on
stroke recovery.” Developmental
Psychobiology. april 2012.