Brain Representation
Each finger has an orderly somatotopic representation on the cerebral cortex in the somatosensory cortex area 3b, part of area 1 and a distributed, overlapping representation in the supplementary motor area and primary motor area.
The somatosensory cortex representation of the hand is a dynamic reflection of the fingers on the external hand: in syndactyly people have a clubhand of webbed, shortened fingers. However, not only are the fingers of their hands fused, but the cortical maps of their individual fingers also form a club hand. The fingers can be surgically divided to make a more useful hand. Surgeons did this at the Institute of Reconstructive Plastic Surgery in New York to a 32-year-old man with the initials O. G.. They touching O. G.’s fingers before and after surgery while using MRI brain scans. Before the surgery, the fingers mapped onto his brain were fused close together; afterward, the maps of his individual fingers did indeed separate and take the layout corresponding to a normal hand.
Read more about this topic: Digit (anatomy)
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