Brain-machine interfaces may soon be here, allowing patients to control prosthetic limbs with their minds, and quadriplegics to move wheelchairs with their thoughts. In a new report published in Scientific Reports, researchers describe a situation in which monkeys were able to control entire wheelchairs with their minds as they moved from one part of a room to another in search of food.

The study is one of the first to achieve “whole-body navigation” in brain-machine interfaces, giving hope to those who are paralyzed and limited to wheelchairs. The researchers aimed to develop technology that would allow a monkey — or in the future, a person — to move “a wheelchair continuously in space,” they write.

Here’s how they did it: A female monkey, equipped with electrodes implanted in her brain, was bound to a wheelchair. The researchers measured her brain activity as she focused on a grape in the room and tried to move toward it. They remotely controlled the wheelchair and moved it forward as the monkey desired to go towards the grape. They were thus able to detect a pattern of neural firing in the monkey’s brain which defined the monkey’s thoughts of going toward the grape, and programmed the wheelchair’s brain-machine interface to respond to that pattern. Shortly after, they allowed the wheelchair to move on its own as the monkey once again saw a grape at the other end of the room and wished to move toward it. Amazingly, the wheelchair moved on its own to the grape, allowing the monkey to grab it and eat it.

Perhaps most interestingly was that over time, the monkeys learned to control the wheelchair with their minds; the researchers no longer had to strap them into the machine. “That wheelchair was being assimilated by the brain as an extension of the monkey’s own body,” Dr. Miguel Nicolelis of Duke University, senior author of the study, told the LA Times.

While the notion of controlling machines with thoughts may seem a bit like science fiction, this is far from the first experiment that has developed the use of brain-machine interfaces. In fact, the technology is closer to being a reality than being the stuff of fiction. Nicolelis has been working on developing brain-machine interfaces for decades in the hopes of providing paralysis patients with new freedom of movement. One of his most ambitious projects has been working on developing a mind-controlled exoskeleton which, in a way, would free people from their paralyzed bodies.

Earlier this year, a man named Johnny Matheny became the first amputee to receive an advanced prosthetic device as an arm that could be controlled with his thoughts. Researchers at Johns Hopkins University developed the arm that could be both technologically advanced but also incredibly comfortable and flexible. And in 2015, researchers developed and improved a program that would allow amyotrophic lateral sclerosis (ALS) patients to move cursors on a screen using their thoughts. There’s also the “stentrode,” a tiny brain-machine interface that could one day help quadriplegics control movement in exoskeletons, wheelchairs, or prosthetic limbs.

However, it will be quite some time before this mind-controlled wheelchair can be used by humans; the researchers will first have to test it in a clinical setting, and also consider whether all patients will want electrodes implanted in their brains. Regardless, the Duke University research team believes it's a big step forward in understanding how the brain may be capable of accepting a thought-controlled machine as part of the body.

Source: Rajangam S, Tseng P, Yin A, Lehew G, Schwarz D Nicolelis M, et al. Wireless Cortical Brain-Machine Interface for Whole-Body Navigation in Primates. Scientific Reports, 2016.