Nearly all amputees continue to feel their missing limb as if it still existed, and many
experience chronic phantom limb pain (PLP). What is the origin of these sensations? There
is currently a broad consensus among investigators that PLP is a top-down phenomenon,
triggered by loss of sensory input and caused by maladaptive cortical plasticity. We tested
the alternative hypothesis that PLP is primarily a bottom-up process, due not to the loss of
input but rather to exaggerated input, generated ectopically in axotomized primary afferent …