Phantom pain

After amputation of a limb patients experience the sensation that the limb is still present and can be painful (i.e., phantom pain). The Phantom sensations can also follow loss of other body parts (e.g., mastectomy). Children born without limbs have influential, non painful, phantom limb sensations. This involves that complete somatotopic representations can exist in the absence of peripheral inputs, and this is the situation in amputees. The cause of phantom pain is unclear. However, it almost certainly involves re-wiring of the somatosensory cortex so that neurons that have lost their original inputs acquire functional connections from previously silent synapses established by neighboring cells. This accounts for how phantom limb sensations can be elicited by touching other sections of the body, generally the face. With continuing cortical re-organization phantom sensations may fade over time.