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