For a great number of people with paralyzed limbs, the reason that they can't move the arm or leg in question is because the "move" command isn't able to reach from their brain to the limb. This is often due to damage to the nervous system, or to the brain, although the limb itself is still perfectly functional ... so it could still move, if only there was a way of getting the signal to it. Well, one might be on its way. Scientists at the University of Michigan have developed an implant known as the BioBolt, that wirelessly transmits neural signals from the brain to a computer. In the future, that computer could hopefully then relay them onto a formerly-paralyzed limb.

Neural implants do already exist, although previous attempts have required an access hole in the patient's skull to remain open while the device is in use - not all that practical for everyday use. The BioBolt, by contrast, would sit underneath the skin and within a hole in the skull, effectively sealing it.

True to its name, the device (which is about as wide as a dime) does indeed look like a bolt. It has a film of microcircuits on the bottom, which sit in contact with the brain. Those microcircuits detect the firing of neurons, and based on the patterns of those firings, are able to recognize certain commands. Using the patient's skin as a conductor, the BioBolt then amplifies, filters and digitizes those signals, then transmits them to an external computer. The incorporation of the conductive qualities of the skin is a key part of the technology, as this allows the implant to use relatively little power for its wireless transmissions.

Down the road, it is hoped that the computer could be replaced with wearable electronics, that might take the form of a watch or even a pair of earrings. Those electronics could send the brain signals directly to the muscles of paralyzed limbs, stimulating them to perform the desired movements. The University of Michigan researchers, however, state that such a system is still years away.

The BioBolt was presented last week at the 2011 Symposium on VLSI Circuits in Japan.

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