This image shows immature neurons in layer II of sheep cerebral cortex. Neurons labelled in red express the cytoskeletal protein Doublecortin, typically found in immature or newly-generated cells. The marker of mature neurons HuC/D (green) is present in several nerve cells of the same layer, and shows a faint immunoreactivity only in a subset of Doublecortin-positive cells, thus indicating the existence of different degrees of immaturity.Neurons generated embryonically but remaining immature in adults are particularly abundant in large-brained, long-living mammals such as sheep. For more information see the article by Piumatti et al. (pages 826–842).