Double-hand transplantations could switch the handedness of patients. Two men who lost both hands in work injuries received transplants after three to four years of waiting. Despite such a long time—the brain typically reassigns areas linked with control of the amputated limb to other muscles— researchers at the French Center for Cognitive Neuroscience in Lyon found the patients’ brain could connect to the new hands, which subsequently could perform complex tasks (in a demonstration, one patient repaired electrical wires). Although both men were righthanded, their left hand connected with their brain at least a year sooner than their right hand did, and they stayed left-handed. The reason for this switch, reported online April 6 by the Proceedings of the National Academy of Sciences USA, is unclear—perhaps the prior dominance of the right hand made the corresponding brain regions less flexible to reconnections or the surgeries were done slightly differently.
Source of Information : Scientific American(2009-06)