After Erik Sorto was hit by a gunshot aged 21, he was paralysed from the neck down. But now he's become the first man in the world to be fitted with a neural prosthetic implant in the region of the brain were intentions are formed.
The prosthetic allows him control of a robot arm, capable of a range of actions, including shaking hands, drinking beer, and even playing rock, paper, scissors. It's capable of significantly more natural movement than other, similar, implants.
Most neural prosthetics are characterised by a delayed, jerky motion, as they're located in the region of the brain associated with movement. The team behind Sorto's implant wanted to try a new approach - locating the implant in the posterior parietal cortex (PPC), a region of the brain associated with intent to move, instead.
As a result, Sorto's arm has much more natural and fluid motion. "The PPC is earlier in the pathway, so signals there are more related to movement planning -- what you actually intend to do -- rather than the details of the movement execution," said Richard Andersen, who was part of the team who installed the arm.
Sorto says he was surprised how easy it was to learn how to use the arm. "I remember just having this out-of-body experience, and I wanted to just run around and high-five everybody," he says. "I really miss that independence. I think that if it were safe enough, I would really enjoy grooming myself - shaving, brushing my own teeth. That would be fantastic."
Details of the implant, which was installed in 2013, have just been published in Science.