The result of proper neuronal migration through the cortical plate (CP) is an inside-out arrangement of neurons, where the younger neurons migrate past the older neurons to their proper locations. Studies in reeler mutant mice show that knocking out the "reeler" gene results in aberrant migration as well as outside-in layering, in which younger neurons are unable to travel past the older ones. Such abnormal layering is also seen in "VLDLR"−"apoER2"− and "dab1"- mutants, indicating the importance of this entire pathway in cortical migration of the developing embryo.