In the developing mammalian cerebral cortex, newly generated neurons migrate toward the pial surface to form a mammalian-specific six-layered cerebral cortex. Genetic studies of human neurological diseases have suggested the involvement of several molecules in cortical neuronal migration. In vivo electroporation is another powerful tool for understanding the molecular mechanisms of neuronal migration. By using these techniques, however, it is difficult to understand molecular basis of time-dependent changes of neuronal morphologies. Here, we introduce a pharmacological approach to cerebral cortical development. Major advantages of the pharmacological approach include the transient suppression of molecules of interest and analyzing time-dependent changes of neuronal morphologies. It also allows us to search molecules regulating neuronal migration with comparative ease. We propose the complementarity between the pharmacological approach and genetics or in vivo electroporation experiments.