Astrocytes promote neuronal migration from SVZ explants. A, SVZ explants were plated on tissue culture dishes alone or in the presence of glia (10,000 or 50,000 astrocytes per well). After 1 DIV, explants were fixed and labeled with antibodies against class III β tubulin. Scale bar, 100 μm. B, The mean maximum distance of migration was calculated for SVZ explants in the absence or presence of astrocytes purified from either the RMS or cerebellum. In the presence of 50,000 astrocytes per well, cells from SVZ explants moved more than three times as far as cells in the absence of additional glia (p < 0.0001). Glia purified from either the RMS or cerebellum (Cb) are equally capable of promoting migration from SVZ explants. The error bars represent SEM.