Functional reinnervation in kitten visual cortex

MOST cells in the adult cat visual cortex, and even in the very young kitten can be activated by visual stimuli presented to either eye^1-3. The retention and refinement of these normal binocular connections depends critically on simultaneous correlated visual experience through both eyes early in life. If a kitten is deprived of vision in one eye during a 'sensitive period', which stretches from about 3 weeks to 3 months, the normal pattern of functional connections is grossly disrupted; the deprived eye loses its influence and most cells can only be driven by stimuli through the experienced eye⁴. Blakemore and Van Sluyters⁵ have recently shown that this situation can be partly or totally reversed by covering the previously experienced eye and opening the deprived eye, and allowing that eye a substantial period of visual experience. Thus one set of afferent terminals, robbed of almost all influence in the visual cortex, can re-establish working connections. We have now analysed the form and rate of this functional reinnervation.