Two monkeys feed themselves with human-like robotic arm

Researchers in the US have taught two monkeys to feed themselves with a human-like robotic arm using only signals from their brains, scientists at the University of Pittsburgh School of Medicine said.

The scientists implanted tiny probes in the area of the animals' brains where voluntary movement originate as electrical impulses.

Specially designed computer software then transmits these impulses to the robotic arm, which carries out the actions the monkey intended to perform with its own limb, according to the scientists.

Video supplied by the University of Pittsburgh School of Medicine shows the monkeys directing the robotic arm and opening and closing a two-finger gripper to feed themselves marshmallows and chunks of fruit while their own arms are gently restrained in tube-like devices.

The technological advance lays the groundwork for development of prosthetics for people with spinal cord injuries and physically "locked-in" diseases like the Lou Gehrig's disease, where some of the body's muscles fail to work.

The monkeys first learned to manoeuvre the robotic arm to deliver tasty treats into their mouths using a joystick, then moved on to hands-free control using brain signals alone, according to the scientists.

Co-author Chance Spalding, a graduate student in the department of bioengineering, said the two monkeys, named Arthur and Pearce, took only about a week to train.

The time it takes for the monkey to see the food and activate the arm is about 150 milliseconds, about the same time it takes a human to decide to move and for a limb to respond, he said.

While the robotic arm looks somewhat industrial and unwieldy, the interface with the monkey's brain is anything but.

The probes, or electrodes, inserted into the neuronal pathways in the animal's motor cortex are as fine as a human hair.

The Pittsburgh scientists' latest endeavour isn't the first to employ brain-machine interface technology, but Spalding said it's the first time the technology has been used in this way.

The goal is to help people who have lost physical function through injury or disease.

Spalding said his lab hopes to begin trials of the brain-controlled robotic arm in people with severe immobility disorders within two years.