Researchers have wired the brains of monkeys to control robotic arms — a feat that could one day allow paralyzed people and amputees to move artificial arms and legs merely by thinking.
The wires fed electrical impulses from the brains of two monkeys into a computer linked to robotic arms. When the monkeys reached for food or manipulated a joystick, the robotic arms mimicked those motions.
For people who are paralyzed because of spinal cord injuries or diseases of the central nervous system, such wiring could one day enable them to bypass the damage and send impulses directly to their muscles.
“It is in the realm of reality. It is not science fiction any more,” said researcher Miguel Nicolelis of Duke University in North Carolina.
More Wires, Better Direction
In the monkey experiments, 96 wires, each half the thickness of a human hair, were connected to six areas of one animal’s brain, while 32 wires were connected to two areas of the second monkey’s brain.
The robotic arms performed simple to-and-fro movements similarly with each monkey. But they performed three-dimensional movements better when directed by the monkey with more implants.
The Duke researchers’ findings were reported in Thursday’s issue of the journal Nature.
They are now working on a chip that could be implanted under the skin, replacing the external computer.
Dr. Roy Bakay of Rush Presbyterian Hospital in Chicago, who helped develop a system to allow a paralyzed human to control a computer cursor with brain implants, said devices to enable people to perform routine tasks could be developed rather quickly.
But it will be a long time before artificial limbs can be made to perform more complex tasks such as throwing a ball, he said.
Such devices would have to be designed with fail-safe systems that would turn the device off during sleep or if the patient had a seizure. The equipment would also have to be made small enough to be portable.
“I would imagine in the next decade we’ll see some prosthetic devices that are going to give patients the ability to do simple things, turn on the TV,” Bakay said. “And then in a few more decades, to be able to get up and move around independently.”
Prosthetics of the Future
Current prosthetic devices for amputees can read electrical impulses from the remaining muscles and operate mechanical hands, arms and legs, but devices have not been developed yet for those paralyzed from the neck down, said John W. Stephenson, clinical coordinator of the prosthetics department at the Texas Scottish Rite Hospital for Children in Dallas.
In March, researchers in Belgium announced an experimental system that allowed a man paralyzed from the waist down to walk using electrodes attached to leg muscles. The electrodes were connected to a chip that mimics signals sent by the brain.
Sandro Mussa-Ivaldi, a researcher at Northwestern University Medical School in Chicago, said that while the Duke researchers were able to transmit information from brain to robot arm, a method also needs to be developed to transmit information back again.
“Which is something we still don’t have a clear idea how to do,” Mussa-Ivaldi said. “The problem is when you think about your arm, it’s not just receiving commands. It also sends information back because you have touch information being sent.”