Brains, Programming Languages, Disconnected Enthusiasms

Thursday, April 26, 2007

Redundancy is for chumps

The Deepest Cut: a New Yorker piece about medical hemispherectomies.
The bulk of the article documents the lives of doctors and patients. Ignore the fluff and you'll find some good neuroscience. The primary lesson here has been said before but it's worth reiterating: neural plasticity is solely responsible for the anatomical structures of the brain

Leah Krubitzer...removed large pieces of the brains of newborn marsupials. Once the marsupials became adult, she examined the brains again and found that they had organized themselves in such a way that the visual, auditory, and other somatosensory areas were all in the same relative positions that they would occupy in a normal brain, but they were smaller, commensurate with the total space available.
The article contains several anecdotes of people recovering lateralized brain functions after the relevant hemisphere had been removed. Apparently, even the lateralization of language can rewired: if the left hemisphere is removed the right hemisphere will adapt to generate and understand language. In the only cited example a 13-year old had her left hemisphere removed and regained her speaking ability. Presumably this is after the critical period. Could language switch hemispheres even in adults?