Figure 1. Schematic diagram of the “inside-out” cortical layering process in (a) wild-type and the “outside-in” cortical layering process in (b) reeler mutant development.

The arrow indicates the progression of time. Layers VI, V, IV, III and II arise successively from neurons entering from the IZ. Although blending between layers occurs at the nominal boundaries, the existence of identifiable layers and the different spatial order of the layers in wild-type and reeler mutant is well established. For clarity the layers are shown to be distinct here. Only the layering (and not the preplate splitting) is shown in these figures.