Cover legend: Newly emerging plp-activated neural progenitor cells at the third ventricle in the prethalamus of an E13.5 plp-shble-lacZ mouse embryo. β-Galactosidase antibody (in red) marks the activated progenitors; blbp (brain lipid-binding protein) antibody (in green) identifies these progenitors as radial glial cells; nuclear marker Hoechst (in blue). The picture was taken on a confocal laser microscope (Leica). For more information, see the article by Delaunay et al. in this issue (pages 2551–2562).