Chains contain neuronal precursors and astrocytes. SVZ explants were cultured for 4 d, fixed, and stained with a nuclear dye (Hoescht 33342) and antibodies against class III β tubulin and anti-GFAP antibodies. Most of the cells in the chains are neuronal precursors (class III β tubulin-positive), but networks of GFAP-positive fibers are also present in the chains. Scale bar, 60 μm.