File:Cortical plate development.jpg

Preplate stage of cerebral cortex development. Preplate neurons are dark blue; undifferentiated ventricular zone cells are green; radial glia are purple; and Reelin, produced by Cajal-Retzius cells, is represented by light blue dots. (a) Separation of the preplate into subplate and marginal zone by the developing cortical plate in wild-type mice. Future layer VI neurons are orange; future layer V neurons are red. (b) In reeler mutant mice, the developing cortical plate fails to separate the preplate into two layers. Neurons that should become layer V (red) do not by pass the neurons that should become layer VI (yellow). In the reeler cortex, the dendritic processes are arranged in a haphazard manner, whereas the axons are mostly normal.