Cell arrangement is impaired in the cortex due to DBZ deletion. A, Neuronal cell arrangement was altered by DBZ deletion. The thymidine homologs CldU and IdU were consecutively injected at E13.5 and E16.5, respectively, and the localization of labeled cells was observed at P2 in layer II/III (II/III). B, Distributions of CldU- and IdU-labeled cells in the cortex. The cortex was divided into 10 bins, and the labeled cells in each bin were counted. C, Immunohistochemistry against the proliferation marker Ki67 in an E15.5 mouse cortex. Scale bar, 200 μm. D, The labeled cells in each bin were counted. The values represent the mean ± SEM; *p < 0.05.