快猫短视频

WOULD you believe that zapping your head with electricity could help you keep
your balance? The trick is to manipulate the nerve signals that help your brain
work out precisely which direction is vertical.

We normally keep our balance by monitoring input from three sources鈥攐ur
eyes, our 鈥渟omatic鈥� system, which includes our sense of touch, and the
vestibular system, a set of fluid-filled tubes in the inner ear. If we move or
sway, tiny hairs pick up disturbances in the fluid, and nerves send signals to
the brain from each ear.

Jim Collins鈥檚 team from Boston University is using an established technique
called 鈥済alvanic vestibular stimulation鈥� (GVS) to apply a small, painless
electric current behind each ear. The current affects the firing rate of the
nerves that carry signals from the inner ear to the brain. But rather than using
GVS to study balance, Collins鈥檚 team want to control or enhance balance.

You can fool the brain and make someone sway from side to side by boosting
the signal behind one ear and dampening it at the other. 鈥淲e鈥檙e causing a shift
in the perception of what is vertical,鈥� says Collins. 鈥淚t feels as if you have
尘辞惫别诲.鈥�

Several groups of researchers are using GVS to probe how our balance system
works, including neuroscientist Brian Day from University College London. 鈥淭he
brain thinks the body has moved, and tries to compensate for that,鈥� says Day.
The strength of the effect depends on the size of the current. 鈥淚t鈥檚 stunning to
watch,鈥� says Collins. 鈥淵ou can get knocked over.鈥� So far they have managed to
improve the balance of healthy volunteers by applying an electric current to
counteract the motion of a swaying platform. This helped them compensate and
stay upright.

Collins hopes that the technique could be built into a prosthesis people will
wear to modify their balance. The first applications would probably be ones that
don鈥檛 require complex feedback from the environment. 鈥淲e鈥檙e trying to design a
鈥榲estibular clamp鈥� that would heighten or reduce the function of the vestibular
system,鈥� says Collins. Boosting the signal could help people with certain
balance disorders, while dampening it might stop astronauts on spinning
spacecraft from feeling so sick.

Eventually Collins hopes to develop a system that can monitor a person鈥檚 body
and environment to influence their balance in a more targeted way. 鈥淭hat鈥檚
difficult to do. You might need an accelerometer attached to the gear that was
able to detect the movements of a subject and link to some kind of smart
controller,鈥� he says.

This might help people to stay upright easily on moving vehicles or ships, or
correct people who sway as they walk. Another use might be in virtual reality.
Electrodes behind the ears linked to a VR headset could make the sensation of
movement completely convincing. 鈥淵ou want the person to experience the full
environment,鈥� says Collins.

鈥淚t鈥檚 very ambitious,鈥� comments Day. 鈥淚t鈥檚 a tall order to put it into a
real-life prosthetic.鈥�