Neural Implants

Brain implants may one day help people who are paralyzed or unable to
communicate because of spinal injury or conditions such as Lou Gehrig's
disease. Electrodes implanted in the brain could pick up neural signals and
convey them to a prosthetic arm or a computer cursor. 

However, implanted electrodes are usually unable to sense consistent neuronal
signals for more than a few months. This loss of sensitivity can be caused
by: shifting of the electrodes, tissue build-up on the electrodes, or death
of the neurons emitting the signals. 

To get around these problems, developers at the California Institute of
Technology in Pasadena created a device, called the autonomous microdrive, in
which the electrodes sense where the strongest signal is coming from, and
move towards it. 

Mounted on the skull, the prototype uses piezoelectric motors to move four
electrodes independently of each other in 1-micrometer increments. The
microdrive also has a collision avoidance capability to keep it from damaging
neurons. 

Within a year researchers expect to fit a paralysed person with a microdrive
implant that allows control of a computer cursor to navigate the Web. 

Read the complete story and view an illustration at:
http://link.abpi.net/l.php?20041116A7