This image shows a section of brain from an embryonic day 18 (E18) mouse lacking the motile cilia gene Ccdc39. These mice develop progressive hydrocephalus starting at postnatal day 1, with thinning of layers II-IV by postnatal day 8, but at E18, cortical layers are well retained, as indicated by staining with markers of layers II-IV (SATB2; red), layer V (CTIP2;green), and layer V1 (TBR1; purple). For more information, see the article by Iwasawa et al. (pages 1820–1844). Cover image by Iwasawa E.