Researchers Train Monkeys To Move Virtual Limbs With Their Minds

By Brent McKnight | Published

This article is more than 2 years old

MonkeyIt seems so simple. You think to yourself, “hey, self, I want to reach out and pick up that glass of water,” and you reach out and pick up that glass of water, or candy bar, or beer, or damn near anything your little heart desires. In reality, however, this is a hugely complex process. Scientists have been trying to create prosthetic limbs that recipients control with their minds for years. Now, thanks to those adorable monkeys, researchers may have taken a huge step towards that goal.

Scientists have been working to developed brain-machine interfaces, which, though way more complicated, are exactly what they sound like. When you think about what action you want your body to perform, your brain sends out electric impulses. Your muscles receive these, and react. When the limb has been amputated and is no longer there, your brain still sends out messages, there’s just nothing there to receive them. The idea behind the BMIs is to create prosthetic limbs that can pick up and interpret this information, and move accordingly.

There have been successes in this field, like a paralyzed woman using a robotic arm to eat chocolate last year, but they have been limited, and progress has been slow. So far, BMIs have been single limb endeavors like this, but for something more complex, like an exoskeleton to make the paralyzed walk, is a whole other animal. But a team at Duke University has made what could turn out to be a big leap in the field.

The team trained a pair of monkeys to control the arms of a virtual avatar using only their minds. One male and one female monkey had electrodes implanted in their brains that measured the activity of 500 neurons. This is the largest number that has been measured in similar experiments. An algorithm in the program interprets the neural signals. Their task was to use the computer generated avatars to put both hands on a circle and hold it there for 100 milliseconds. If successful, the subjects received a tasty juice treat. That better be some damn tasty juice to make up for having wires stuck in your brain.

The female monkey performed this task using a pair of joysticks, but because amputees don’t have that luxury, the male monkey only allowed to use his mind while observing the task. Over time the researchers noticed that the patterns in which their neurons fired changed over time, as their brains adapted to the BMIs, and the findings indicated that cells react differently when working to move multiple limbs, as opposed to a single one.

This is a lengthy process—the female monkey took nearly a year to master the task, and then only had around a 45% success rate—but the scientists are optimistic that the results can improve, and this is one hell of a first step.

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