We're already using the tongue to replace optical input for people who have been blinded. There's also the possibility of tapping in at the ears, the spinal co

We're already using the tongue to replace optical input for people who have been blinded. There's also the possibility of tapping in at the ears, the spinal cord, hell, it's entirely conceivable you could cut off a hand and attach an implant there. When you think about the amount of bandwidth that your mind has between your hand and your brain (seriously, move your hand a bit and think about how much data that is in absolute terms) there's a whole lot of bandwidth in established connections, especially for someone who has been maimed and has brain pathways lying dormant for controlling a limb.