No difference in BrdU labeling between wild type and Psen1−/− embryos. Pregnant female mice received one injection of BrdU at E11.5 and BrdU immunostaining was performed on sections of E15 brain. Coronal sections from the lateral telencephalon of wild type (A, C, E) or Psen−/− embryos (B, D, F) are shown immunostained for BrdU (A, B), labeled with DAPI (C, D), or as merged images (E, F). The marginal zone (MZ), cortical plate (CP), subplate region (SP) and intermediate zone (IZ) are indicated. Scale bar: 100 μm.