Scientists have wired up the brain of a rat so it can move a robot arm by thought alone, it was reported yesterday. It is the first time brain signals have been used to control a robotic device.
The experiment, conducted in a US laboratory, brings the science fiction world of thought-operated computers, mechanical devices and prosthetic limbs a step nearer.
A team led by Dr John Chapin, from the MCP Hahnemann Medical College, in Philadelphia, first trained six rats to press a lever bar which operated an electric robot arm, bringing them water.
Using implanted electrodes, the scientists found that the bar-pressing paw movement was preceded by a burst of activity from a certain group of neurons.
By recording signals from 32 selected neurons, a system was developed which allowed the brain cells to operate the robot arm directly.
Signals from the implants were fed to a computer, processed and used to generate the electric current needed to power the arm. The rats could then obtain their reward simply by thinking of pressing the bar, instead of having physically to press it.
After a short time most of the rats learned the trick, and stopped going through the motions of pressing the lever, or pressed it less often.
Writing in the journal, Nature Neuroscience, the scientists said the results raised the possibility of restoring movement to paralysed patients by allowing their brains to control external devices, or even their own muscles.
In an accompanying article, Dr Eberhard Fetz, from the University of Washington School of Medicine, in Seattle, said the work had far-reaching implications, assuming the technical problems of recording the output of brain cells could be solved.
He wrote: "Given the possibility of reliably extracting real-time information from neural populations, we can imagine many symbiotic interactions between brains, computers and prosthetic devices. The annals of science fiction and current movie offerings are replete with imaginative scenarios."
He continued: "The extent to which these possibilities are realised will depend on overcoming some real-life technical obstacles, but these in principle seem ultimately surmountable."
Scientists at Emory University in Atlanta, Georgia, made headlines last year by designing brain implants that allowed paralysed patients to move a computer screen cursor by the power of thought.
In January researchers in Germany and the US went a step further, enabling paralysed patients to "think" words on to a computer screen via electrodes attached to their scalps.
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