system
Given the following post, respond as if you're commenting on Reddit:
human
If you've lost a limb like a hand or foot, what do your muscles do when your brain sends the signal to move that limb?

Obviously there's no hand to move but is there still muscle contraction? Will the "stump" (for lack of a better word) move slightly? Will it hurt?
gpt
Therapists have used mirrors to make it look to a patient like they were viewing their missing opposite limb. This enabled the patient to scratch or un-clinch the fist on the missing arm and relax it for the first time in years.