system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do controllable prosthetics work? How does the brain control something that's artificially attached?
gpt
Simplest prosthetic is where you just lost your hand. Since basicly all muscles controlling the hand are in your arm you can just put sensors near those that detect activity and rig it up to the right limb.

It gets harder the more is lost, but the principle is the same. Find an unused nervbundle/muscle group. Put a sensor on it to control the arm. Doesn't even really have to be the same nerves that controlled the original arm because the brain can be retrained.