Paralysed man sends e-mail by thought

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Published online: 13 October 2004;

Paralysed man sends e-mail by thought

Roxanne Khamsi

Brain chip reads mind by tapping straight into neurons.

Controlling objects with thought is becoming a reality.

 

© Alamy

 

An pill-sized brain chip has allowed a quadriplegic man to check e-

mail and play computer games using his thoughts. The device can tap

into a hundred neurons at a time, and is the most sophisticated such

implant tested in humans so far.

 

Many paralysed people control computers with their eyes or tongue.

But muscle function limits these techniques, and they require a lot

of training. For over a decade researchers have been trying to find

a way to tap directly into thoughts.

 

In June 2004, surgeons implanted a device containing 100 electrodes

into the motor cortex of a 24-year-old quadriplegic. The device,

called the BrainGate, was developed by the company Cyberkinetics,

based in Foxborough, Massachusetts. Each electrode taps into a

neuron in the patient's brain.

 

The BrainGate allowed the patient to control a computer or

television using his mind, even when doing other things at the same

time. Researchers report for example that he could control his

television while talking and moving his head.

 

The team now plans to implant devices into four more patients.

 

Brain waves

 

 

 

 

The tiny sensor consists of an array of 100 electrodes to capture

signals from the brain.

 

© Alamy

 

Rival teams are building devices to read brain activity without

touching neurons. Neural Signals, based in Atlanta, has patented a

conductive skull screw that sits outside the brain, just under the

skull. Other researchers are developing non-invasive technologies,

for example using an electroencephalogram to read a patient's

thoughts.

 

But BrainGate's creators argue that such techniques only give a

general picture of brain activity, and that the more direct approach

allows more numerous and more specific signals to be

translated. "This array has 100 electrodes, so one can theoretically

tap into 100 neurons," says Jon Mukand, an investigator on the team

based at the Sargent Rehabilitation Center in Rhode Island.

 

This makes the technology faster and more flexible, he argues. "It's

far more versatile when one can get a larger number of neurons."

 

But Stephen Roberts, an engineer at Oxford University, UK, who has

worked on brain-computer interfaces, says the field is still waiting

for a breakthrough. "We have to make something that works robustly

and without a lot of patient training," he says. "Most of these

devices work well on a small subset of patients, but there's a long

way to go before getting them to work for the general population."

http://www.nature.com/news/2004/041011/full/041011-9.html