ABSTRACT

Data regarding many aspects of the normal development of the mammalian visual system, as visual deprivation's effects on this development, are rapidly accumulating. The visual system continues to grow both physiologically and morphologically after the animal is born. This statement is probably true of all mammalian species. The timing and duration of this "critical period" when the visual system is susceptible to visual deprivation varies from species to species but probably exists in all mammals. The normal visual environment may play a positive role in the development of the visual system. The developing visual system appears to exhibit a limited degree of compensatory growth following neonatal injury. At the risk of provoking K. S. Lashley's posthumous amusement, this chapter proposes five generalizations that represent a useful assessment of the significance of recent experiments concerning the normal and abnormal development of the visual system in the monkey, cat, hamster, rat, mouse, opossum, and rabbit.