A 28-year-old man presents to your clinic for follow-up care…

A 28-year-old man presents to your clinic for follow-up care after undergoing a below-the-knee amputation following a motor vehicle accident. He expresses concern about experiencing burning and tingling pain in the foot that is no longer there. He asks, “How can I feel pain in a leg that’s gone?” Which of the following best explains the mechanism of his phantom limb pain?