Robot monkeys to cure brain disease

Updated 18.52 Thu May 29 2008
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Monkeys have been trained to operate a human-like robotic arm with their thoughts.

Two animals had their own arms restrained while they fed themselves with the arm, using it to deliver marshmallows and chunks of fruit.

Eventually, the monkeys came to regard the robot arm as part of their own bodies

The experiment is seen as a major step forward towards the goal of creating functional artificial limbs that interact with the brain.

Previously, brain-machine interfaces have allowed both monkeys and humans to control cursor movements on a computer screen.

Other control systems for prosthetic devices have relied on signals generated by tiny muscle movements.

But better technology is needed to help people paralysed by spinal cord injuries or suffering from devastating neurological conditions such as motor neurone disease.

The new experiments took place in the US laboratory of Dr Andrew Schwartz, where much of the pioneering "mind-over-machine" work has been carried out.

Dr Schwartz and his team at the Pittsburgh School of Medicine developed sophisticated computer software to interpret signals from probes the width of a human hair inserted into the monkeys' brains.

The signals were translated into instructions to a computer, which guided the robot arm.

Actions the monkeys intended to perform with their own limbs were instead carried out by the machine.

Movements were "fluid and natural", according to the researchers who reported the results of the experiment in the journal Nature.

Eventually, the monkeys came to regard the robot arm as part of their own bodies. The were able to use the arm without being distracted by outside disturbances or noise.

Dr Schwartz said: "Our immediate goal is to make a prosthetic device for people with total paralysis.

"The monkey learns by first observing the movement, which activates his brain cells as if he were doing it. It's a lot like sports training, where trainers have athletes first imagine that they are performing the movements they desire."

The probes are placed in neuronal pathways in the motor cortex, a brain region where voluntary movement originates as electrical impulses.

Thousands of nerve cells fire together to perform even the most simple of actions. Capturing the firing pattern of each one would be impossible, so the software is designed to use limited information from about 100 neurons and fill in the missing signals.

Brain-machine interfaces were helping scientists better understand how the brain works, said Dr Schwartz.

He added: "The more we understand about the brain, the better we'll be able to treat a wide range of brain disorders, everything from Parkinson's disease and paralysis to, eventually, Alzheimer's disease and perhaps even mental illness."

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