The loss of sensory input from the amputated limb leads to maladaptive reorganization of the sensory cortex, wherein the deprived area of the primary sensorimotor cortex responds to inputs received from cortical neighbors. Neuronal reorganization in the peripheral somatosensory nervous system leads to maladaptive supraspinal changes such as map remodeling of the sensory cortex, loss of neurons and/or neuronal function, and alterations in neural and glial activity, leading to pain.