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First Bionic Fingertip Implant Delivers Sensational Results (gizmag.com)
Zothecula writes: Dennis Aabo Sorensen may be missing a hand, but he nonetheless recently felt rough and smooth textures using a fingertip on that arm. The fingertip was electronic, and was surgically hard-wired to nerves in his upper arm. He is reportedly the first person in the world to recognize texture using a bionic fingertip connected to electrodes that were surgically implanted above his stump. The device was created by scientists from the Ecole polytechnique federale de Lausanne in Switzerland, and Italy's Scuola Superiore Sant'Anna research institute. While it was wired to Sorensen, a machine moved it across rough and smooth plastic surfaces. Sensors in the fingertip generated electrical signals as they deformed in response to the topography of those surfaces, and transmitted those signals to the nerves in a series of electrical spikes -- this was reportedly an imitation of the "language of the nervous system." He was able to differentiate between the two surfaces with an accuracy of 96 percent.
Ever since I was about 12 (now mid 30's), I wondered what the so-called "language of the nervous system" was. As in, what protocol. Like 9600 Baud 8N1 sending Modbus, there has to be some typical defined format or packet of information.
My gripe is that it never seemed that neurologists had never brought in an electrical engineer or computer scientist to properly map out the "spikes". Seeing the crappy smooth graphs of the spikes or pulsing that nerves are described to do in textbooks, my fear was that they were only seeing grossly distorted spikes and were missing out on the signal nuances as the probe gain could be totally wrong or impedances totally mismatched.
The questions remain, like what does amplitude correlate to, what is the meaning of a period of time between a certain kind of signal spike, and whatnot. It can't just be random throbbing because how is a person able to distinguish what exact finger is feeling what sensation (pressure, wetness, sharpness, high or low temperature, etc)?