Figure 2.

Ventral telencephalic cells can induce the generation of interneurons from dorsomedial progenitors via Shh. A, Schematic diagram illustrates the experimental procedure by which aggregate cultures were prepared from ganglionic eminences and dorsomedial telencephalon. B, The proportion of GABAergic interneurons generated by β-gal+ dorsomedial progenitors was increased in cultures in which dorsomedial progenitors were cocultured with ganglionic eminence-derived cells (M*+GE), compared with the ones in which dorsomedial telencephalic cells were cultured alone (M*+M). Blocking Shh signaling with cyclopamine (5 μm; cyc) diminished interneuron production induced by GE (M*+GE+cyc). A ventrally derived signal or signals increased the proliferation of dorsomedial progenitors (C) and decreased neuronal differentiation (D), suggesting that it delayed neuronal differentiation by stimulating proliferation. These effects of ventral cells were also blocked by cyclopamine. *p = 0.04; **p ≤ 0.009.