Master monkey's brain controls sedated 'avatar'By James Gallagher Health and science reporter, BBC News
Three monkeys
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Robotic arm controlled by thought
The brain of one monkey has been used to control the movements of another, "avatar", monkey, US scientists report.
Brain scans read the master monkey's mind and were used to electrically stimulate the avatar's spinal cord, resulting in controlled movement.
The team hope the method can be refined to allow paralysed people to regain control of their own body.
The findings, published in Nature Communications, have been described as "a key step forward".
Damage to the spinal cord can stop the flow of information from the brain to the body, leaving people unable to walk or feed themselves.
The researchers are aiming to bridge the damage with machinery.
Match electrical activity
The scientists at Harvard Medical School said they could not justify paralysing a monkey. Instead, two were used - a master monkey and a sedated avatar.
The master had a brain chip implanted that could monitor the activity of up to 100 neurons.
During training, the physical actions of the monkey were matched up with the patterns of electrical activity in the neurons.
The avatar had 36 electrodes implanted in the spinal cord and tests were performed to see how stimulating different combinations of electrodes affected movement.
The two monkeys were then hooked up so that the brain scans in one controlled movements in real time in the other.
The sedated avatar held a joystick, while the master had to think about moving a cursor up or down.
In 98% of tests, the master could correctly control the avatar's arm.
One of the researchers, Dr Ziv Williams, told the BBC: "The goal is to take people with brain stem or spinal cord paralysis and bypass the injury.
"The hope is ultimately to get completely natural movement, I think it's theoretically possible, but it will require an exponential additional effort to get to that point."
He said that giving paralysed people even a small amount of movement could dramatically alter their quality of life.