A man loses his right hand in a farm accident, four year later; he has episodes of severe pain in the missing hand (phantom limb pain). A detailed PET Scan study of his cerebral cortex might be expected to show

Ans. (d) Projection of fiber from neighboring sensory areas into the right hand area of his left SI(Ref: Ganong, 25th ed/p.169)Cortical plasticity#Cortical areas become weak with disuse and strong with use#If a digit is amputated, cortical representation of the neighboring digits spreads and occupies the cortical area of the amputated digit. There is tremendous remapping of the somatosensory cortex This is one explanation for phantom pain#Such plastic changes happen for one sensory modality to another if that sensory modality is not use