Adult neural stem cells derived from rat hippocampus (expressing GFP) were induced to differentiate into neurons (MAP2ab positive, red) when co-cultured with hippocampal astrocytes (GFAP positive, gray), but to differentiate into oligodendrocytes (RIP positive, red, in insert) when co-cultured with hippocampal neurons. For details, please see the article by Song et al., Nature, 2002, pp39-44.