Math1-Cre mice were crossed with PtcC/C mice, and brains of WT or mutant progeny were harvested at indicated ages. Brains were fixed and photographed intact (C, G) or sectioned and stained with H&E (A, B, D, E, F, H). Note the enlargement of the cerebellum and severe hyperplasia on the surface at P8 and P21. Scale bars: 30 μm (A, B, E and F); 2.5mm (C and G); 400 μm (D and H).