Paralysed man sends e-mail by thought]

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Paralysed man sends e-mail by thought

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

 

 

 

 

 

 

 

 

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."

 

 

 

 

 

 

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