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.
