Phantom limb is explained by: September 2007

Ans. B: Law of projection No matter where a paicular sensory pathway is stimulated along its course to the coex, the conscious sensation produced is referred to the location of the receptor. This principle is called the law of projection. Coical stimulation experiments during neurosurgical procedures on conscious patients illustrate this phenomenon. For example, when the coical receiving area for impulses from the left hand is stimulated, the patient repos sensation in the left hand, not in the head. Another example is seen in amputees. Some of these patients may complain, often bitterly, of pain and proprioceptive sensations in the absent limb (phantom limb). The ends of the nerves cut at the time of amputation often form nerve tangles called neuromas. These may discharge spontaneously or when pressure is put on them. The impulses generated in them are in nerve fibers that previously came from sense organs in the amputated limb, and the sensations evoked are projected to where the receptors used to be.