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TOM COSTELLO: Imagine moving a mechanical arm by just thinking
about it. Or playing a video game using only your mind.
Although it may seem like science fiction, scientists and
engineers have been developing this technology for decades:
it's called brain-computer interface, or BCI.
RAJESH RAO: The field of brain-computer interfaces relies
on the ability of the brain to be able to generate certain
types of responses that can then be harnessed by computers, to be
able to be interpreted by computers.
COSTELLO: Doctor Rajesh Rao is a neuroengineer and director of
the Center for Sensorimotor Neural Engineering at the
University of Washington, and is funded by the National Science
Foundation. He is developing safe, non-invasive devices that
can connect to the brain to accomplish things like
controlling a prosthetic arm, or sending commands to a computer.
RAO: Looking at the development of this whole
field of brain-computer interfaces is to think of it in
terms of studying how the brain controls the body.
COSTELLO: Whether it's telling the legs to jump in the air, or
activating glands to produce sweat, the body's actions and
functions are controlled by neurons. They communicate
information to and from the brain and the rest of the
nervous system using chemical and electrical signals.
RAO: And so they're sending these electrical pulses to each
other and eventually to the muscles that are then
controlling my body.
COSTELLO: Much like how the brain controls muscles,
researchers can use new technologies to tap into these
signals to control machines.
RAO: The understanding of how the brain controls movement led
to the development of devices and algorithms - that can be
implemented on a computer that recognize these patterns in the
activity of brain cells and then correspondingly move
an artificial device.
COSTELLO: To demonstrate how this technology works, Rao and
his team of students use a BCI that allows them to study
nonverbal communication. First, the student is fitted with an
electroencephalogram or EEG cap, which is a series of electrodes
placed on the scalp to record brain signals.
COSTELLO: When a question appears on the monitor, the
student answers "yes" or "no" by looking at one of the flashing
lights, which are blinking at different frequencies. When the
subject's eyes focus on one of the response lights, the
frequency of that specific light is picked up by the visual
cortex in the brain, and measured by the EEG cap. 12
hertz represents a "yes" frequency, while a "no" is at
a frequency of 13 hertz.
STUDENT: Now you can see it peak here at around 12 hertz because
no is for 12 hertz.
COSTELLO: The computer interprets this signal and moves
the cursor in the direction of the response. Using an EEG cap
isn't the only way to measure brain activity. Some BCI's use a
method called electrocorticography. It also
records brain activity but unlike the EEG cap, it is
surgically placed directly on the surface of the brain,
providing a clearer signal and more precise information.
RAO: For example, they can imagine moving their hand. And
we use a computer to extract the patterns that correspond to
imagined movement of the hand compared to, for example,
not imagining and just resting.
COSTELLO: From there, the computer can distinguish the two
types of brain activity: imagining movement and not
imagining movement, then use that information to enable hand
control by mental activity.
RAO: Given the right kinds of information and the right kinds
of devices that are useful for the animal or for the human,
the brain can start to adapt.
COSTELLO: With practice, the brain can learn to do something
it's never done before, like control a prosthetic it's not
familiar with. But the key is to understand how these neural
networks communicate between the brain and the body.
RAO: If you're able to understand the brain better,
then you're also able to build better brain-computer
interfaces, because they can use those signals that are
responsible for different kinds of movements.
COSTELLO: As Rao continues to collaborate with engineers,
neuroscientists, and neurosurgeons to develop more
BCI devices, he is working toward a future where the brain
and technology come together seamlessly.
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