Most of us don’t think twice when
we extend our arms to hug a friend or push a shopping cart—our limbs work
together seamlessly to follow our mental commands. For researchers designing
brain-controlled prosthetic limbs for people, however, this coordinated arm
movement is a daunting technical challenge. A new study showing that monkeys
can move two virtual limbs with only their brain activity is a major step
toward achieving that goal, scientists say.
The brain controls movement by
sending electrical signals to our muscles through nerve cells. When
limb-connecting nerve cells are damaged or a limb is amputated, the brain is
still able to produce those motion-inducing signals, but the limb can't receive
them or simply doesn’t exist. In recent years, scientists have worked to create
devices called brain-machine interfaces (BMIs) that can pick up these
interrupted electrical signals and control the movements of a computer cursor
or a real or virtual prosthetic.
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