This is extremely
promising, particularly because it is possible to develop sonic vortexes able
to concentrate sonic energy on a very small area. This type of tool would provide scalpel like
precision and can be combined with another tool to provide a safe focal point.
Thus we have the
beginnings of actual physical intervention in the brain’s structure as well as
a tool able to plausibly tackle real physical brain damage. Such stimulation could well accelerate the
brain’s natural healing as well.
Best of all, no damage
is incurred in the attempt. Thus
multiple stimulations become possible.
Bravo!
Ultrasound May Boost
Brain Performance
By
Stephanie Pappas, Senior Writer
January
12, 2014 01:00pm ET
Ultrasound
may improve sensory perception, according to a new study in humans.
By
directing ultrasound to a specific brain area, researchers were able to improve
people's ability to discriminate between sensory inputs. Ultrasound is sound
far above the upper limit of what humans can hear. It's useful in medical
imaging. Doctors and technicians send bursts of ultrasound through tissue and
record the echoes, creating a picture of what's inside — whether it's an
injured knee or a fetus in utero.
Ultrasound
also has potential for mapping the connectivity of the brain. Neuroscientists
are particularly interested in understanding how brain areas chat with one
another; in fact, a new federal project, the BRAIN Initiative, has the goal of mapping the
healthy human brain.
Ultrasound
is one of several noninvasive methods that stimulate the brain. Another is
transcranial magnetic stimulation, which stimulates the brain with magnets. A
third is transcranial direct current stimulation, which uses electrodes to
deliver a weak electrical current to the brain through the scalp.
The new study suggests
that ultrasound may be the best of the bunch.
"We
can use ultrasound to target an area of the brain as small as the size of an
M&M," study researcher William Tyler, a neuroscientist at the Virginia
Tech Carilion Research Institute, said in a statement. "This finding
represents a new way of noninvasively modulating human brain activity with a
better spatial resolution than anything currently available."
Surprising improvement
Tyler
and his colleagues focused on sensory perception from the hand. They first
placed an electrode on the wrist, over the nerve that carries impulses from the
hand to the brain. Using a small electrical current, they stimulated that nerve
while focusing ultrasound on the brain region that processes the nerve's
signals.
The
researchers recorded the participants' brain responses with
electroencephalography (EEG), electrodes on the scalp that measure the
electrical activity of the brain. The ultrasound weakened the brain waves that
encode the tactile stimulation, they found.
But
the next set of experiments revealed something truly strange.
The
researchers conducted two tests of sensory perception. In the first, participants feel
two pins against their skin and must distinguish whether they are being touched
at one or two points. The closer the pins are to each other, the harder the
task. In the second, researchers blow a series of air puffs against the
participants' skin, and they must determine how many individual puffs they
feel. The faster the puffs, the harder they are to discriminate.
Instead
of these weak brain signals translating to poorer sensory perception, people's
performance actually improved on both tests.
"Our
observations surprised us," Tyler said. "Even though the brain waves
associated with the tactile stimulation had weakened, people actually got
better at detecting differences in sensations."
Tweaking
the brain
What
might explain this seeming paradox? The answer might have to do with how neurons function. When brain cells
communicate, they can urge their neighbors to become active (excitation) or
tell everyone to quiet down (inhibition). The ultrasound may have affected the
brain region's balance of excitation and inhibition, Tyler said.
As
a result, the excitation impulses may not have spread so far, essentially
giving the brain a better triangulation of where the sensory inputs were coming
from.
The
boost in sensory perception vanished when researchers moved the ultrasound's
focus just a half inch (1 centimeter). That means the method is a
fine-grained way to "tweak" brain circuits, both to map their
activity and potentially to treat brain disorders.
"In
neuroscience, it's easy to disrupt things," said Tyler. "We can
distract you, make you feel numb, trick you with optical illusions. It's easy
to make things worse, but it's hard to make them better. These findings make us
believe we're on the right path."
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