Duke Scientists Train Monkeys To Move Virtual Simian Arms—Using Only Their Minds
Rhesus monkeys in a Duke University lab have learned the ability to move two arms of a virtual monkey--using only their minds. But this brain-computer interface manipulation is not just a neat party trick: researchers hope it will lead to technology that will one day allow paralyzed people to manipulate prosthetic limbs and other assistive devices.
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The Duke professor of neurobiology behind the project, Miguel Nicolelis, showed off a monkey in 2011 that was able to manipulate only one virtual arm using its mind. Now Nicolelis has trained monkeys to move two arms, in the first-ever demonstration of "bimanual," or two-armed, virtual movement.
"Bimanual movements in our daily activities--from typing on a keyboard to opening a can--are critically important," said Nicolelis, who detailed his findings in the journal Science Translational Medicine. "Future brain-machine interfaces aimed at restoring mobility in humans will have to incorporate multiple limbs to greatly benefit severely paralyzed patients."
In Nicolelis's study, two rhesus monkeys were shown simian avatars on a screen and trained to place the avatar's hands on targets. Each monkey used two joysticks to move the virtual monkey, and the real monkey was rewarded with a sip of fruit juice when it properly moved the virtual arms. This practice went on during 20- to 40-minute sessions for a year. Then each monkey was strapped into a chair with its arms pinned down, and the joysticks were taken away. The monkey was hooked up to a brain-machine interface, and by simply thinking about moving the virtual simian's arms, the virtual arms did indeed move. The monkeys were able to do this successfully 75 percent of the time.
The researchers observed that the cortical areas of the monkeys' brains showed widespread plasticity as they improved their control over the virtual avatars. What this means, according to the researchers, is that the monkey's brain actually began incorporating the virtual arms into its own self. In other words, "the animals literally incorporate the avatar as if the avatar was them," said Nicolelis, who explored this idea in another study earlier this year.
Nicolelis will use the rhesus monkey findings to advance his work with the Walk Again Project. Earlier this year, Nicolelis made headlines when he announced an ambitious demonstration he plans to put on during the opening game of the World Cup in São Paulo, Brazil, on June 12, 2014. As Nicolelis wrote on CNN:
[A]t 5:00 pm that afternoon, a Brazilian young adult, who is paralyzed below the waist down will emerge in the pitch wearing a robotic vest, known as an exoskeleton, whose movements are controlled by some sort of brain-derived signals. Then, using all his voluntary will, this true herald of a new era shall walk autonomously all the way to center field, and once there, kick a ball to deliver the official start of the World Cup.
That seems like an incredibly ambitious undertaking, what with the World Cup about seven months away, but Nicolelis told NBC that the project is "on schedule."
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