Postnatal development of the visual cortex and the influence of the environment

In the early sixties, having begun to describe the physiology of cells in the adult cat visual cortex, 1 David Hubel and I decided to investigate how the highly specific response properties of cortical cells emerged during postnatal develop-ment. We were also interested in examining the role of visual experience in normal development, a question raised and discussed by philosophers since the time of Descartes. The design of these experiments was undoubtedly influenced by the observation that children with congenital cataract still have substantial and often permanent visual deficits after removal of the cataract and proper refraction. 2 Also, behavioral studies had shown that animals raised in the dark or in an environment devoid of contours have a similar impairment of their visual functions. 3´4 Because of the difficulties associated with raising kittens in total darkness, we decided to fuse the lids by suture. This procedure prevented any form vision without completely depriving the animal of light. We expected this to be an effective procedure because cortical cells respond to contours and are insensi