Effects of digesting chondroitin sulfate proteoglycans on plasticity in cat primary visual cortex.
Kittens were monocularly deprived by closing one eye at the time of natural eye opening for periods that ranged from 4 to 14 weeks. This eye was then opened, and the other eye was closed for an approximately equal period of time. During this period of reverse occlusion, the vision of the initially deprived eye improved from apparent blindness to a level of good visual acuity. Surprisingly, however, this recovery was largely eliminated in only 2 weeks once the initially nondeprived eye was opened to restore visual input to both eyes. This finding has important implications for the nature of the mechanism(s) responsible for the dramatic physiological effects of monocular occlusion on the visual cortex. It may also help to elucidate recent observations on patching therapy in human amblyopia.