Professor Kevin Warwick has become the world's first cyborg.

A device has been implanted into his arm to both record the day-to-day impulses of normal muscle use and record the reactions his arm has to stimuli coming from the device.

See the article by Polly Curtis for the Unlimited Guardian:
Scientist becomes world's first cyborg

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Here's a clip from the Unlimited Guardian piece:

he implant was designed by Professor Brian Andrews, from the National Spinal Injuries Centre at Stoke Mandeville Hospital, in Buckinghamshire.

It is hoped the experiment will help scientists better understand the nervous system, and restore movement in people after spinal injuries. "The big aim is hopefully about helping people move around again and to control their bodies more," said Professor Warwick.

There is also scope for enhancing the sensory system. One of the laboratory experiments planned over the next three months - the length the device will be in the professor's arm - is designed to give him a sixth sense. By attaching an electronic ultra sound sensor to the device, it is hoped that Professor Warwick will be able to develop the sensory capabilities of a bat, through his arm.

"For me that could be fun," he explained, "but for someone who is blind, it could be immediately useful, it could give them the chance to sense space like a bat. Another application could be for someone with arthritis - we could put a chip in them and electronically remove the pain."