Plasticity and the Visual Cortex

It's in every neuroscience textbook: the kitten that never saw with stereoscopic vision, because Hubel and Weisel sutured one of its eyes shut during the "critical period" of brain development. The moral, at least as I was taught it, was that plasticity has limits. After infancy, our brain begins to harden into shape. If you don't see stereoscopically as a baby, then you never will. Binocular cells don't develop in adults.

Oliver Sacks had an insightful article in The New Yorker a few weeks ago about a woman who seems to disprove Hubel and Weisel's cat. And now, Robert Krulwich has a wonderful version of the story on Morning Edition. Just fascinating.

P.S. Jake Young provides a possible molecular explanation in the comments section below...

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We were just discussing this issue of ocular dominance column plasticity in my behavioral neuro course. Apparently the recent data suggests that the termination of plasticity is created in part anatomically but also in part because of an increase in GABAergic signaling. When you inhibit the GABA, some of the plasticity is restored.

It makes you think that this business with critical periods is somewhat more complicated than previously presented. The reality might be more that plasticity is chronicly suppressed in the adult, not that the adult is incapable of it.