In many sensory systems there is evidence that (1) environmental input at specific times during development is necessary for normal outcomes and (2) if input is missing during such a critical period, cortical pathways will develop abnormally, causing abnormalities in behaviour. For example, when visual input is abnormal during early childhood because one eye is misaligned or has an uncorrected refractive error, a seemingly permanent deficit in vision develops: amblyopia. (This happens in 1% to 5% of the population.) Abnormal input later in development does not cause amblyopia, so a critical period appears to be involved here.
On the other hand, the adult brain is still plastic enough to change after the loss of an eye or a finger or a period of playing video games. This network will build on recent findings like these about unexpected neural plasticity to develop new therapies for adult amblyopia. It will also use amblyopia as a model to re-examine limits to plasticity across domains as diverse as second-language learning, recovery from deafness, birdsong, and recovery from brain damage. The general principles that emerge will have implications for promoting normal development and for the development of therapies for other abnormalities.
Funded by the James S. McDonnell Foundation