The mind-controlled prosthesis with sensation
Photographer: Johan Bodell/Chalmers University of Technology
Touch sensations arise from sensors in the prosthetic thumb. The prosthesis converts the signals from the sensors into electrical signals that stimulate the user's nerves in the arm stump. However, because the organization of the nerve is rather arbitrary, surgeons can’t be sure whether their placement of the electrodes will generate a sensation in the correct location on the thumb. In this long-term study in which the prosthesis was used for over a year in daily life, the users did not report the sensations to migrate to the prosthetic thumb. The sensations remained stable in their original location. This points to a fundamental limit on neural sensory plasticity, which is the ability of our brain to change the experience of touch sensations.