ABSTRACT
In this chapter, the authors explore the mechanisms of nervous system development, with an emphasis on wiring. They devote to wiring the visual system as a primer, since many fundamental insights about brain wiring have come from research on the developing visual system. The ferret visual system is much less mature at birth than that of cats and monkeys, so experiments investigating early visual system development can be effectively carried out in postnatal ferrets. Injection of epibatidine into the eye therefore provided a loss-of-function manipulation for establishing the role of retinal waves in visual system wiring. Powerful molecular genetic approaches in Drosophila have made its visual system a model for addressing general questions regarding cell fate determination and wiring specificity. The formation of the retinotopic map in the visual system offers an excellent experimental system for dissecting the mechanisms by which molecular cues instruct wiring specificity.
