Mo at Neurophilosophy has long been my pick for best neuroscience blogger. In his latest post, he offers an excellent summary of influential research on visual cortex plasticity and recent discoveries that could lead to new treatments for previously untreatable forms of visual impairment.
The classic Nobel Prize-winning studies of David Hubel and Torsten Weisel showed how the proper maturation of the developing visual cortex is critically dependent upon visual information received from the eyes. In what would today be considered highly unethical experiments, Hubel and Weisel sewed shut one eye of newborn kittens. They found that this monocular deprivation had dramatic effects on the visual part of the brain: the columns of cortical tissue that normally receive inputs from the closed eye failed to develop, while those that receive inputs from the other eye were significantly enlarged. The kittens also failed to develop visual cortical areas which normally receive inputs from both eyes, and as a result did not have binocular vision.
The work also showed that this could be reversed, as long as the deprived eye was opened within a specific time window. Thus, the concept of the critical period was established, a concept which remains influential to this day...
Upon the publication of Hubel and Weisel's work, it came to be believed that deprivation of visual experience beyond the critical period led to irreversible changes in the visual cortex. But this has recently been challenged, and the current study adds weight to the notion that visual cortical plasticity can be induced in adult life. It also suggests that a treatment based on Otx2 could one day be available. Such a treatment could in theory promote cortical plasticity after the critical period in amblyopic children, and possibly in elderly patients with failing eyesight. Read the entire post here.