Short term fate map of Math1-lacZ cells generated after conditional ablation of Notch1 in the cerebellar primordium. (a-d) Coronal sections from E14.5 floxNotch1 (a, c) and En1-cre; floxNotch1 (b, d) embryos stained for β-galactosidase activity. Long arrows indicate the approximate position of the MPT and LPB neurons, and short arrows indicate the position of the DCN. (e, f) Immunohistochemical staining for calbindin on adjacent sections to (a, b) shows an increase in the LPB neuron hindbrain population (white arrows). The asterisk in (e) indicates calbindin positive afferents that are absent in the mutants. Quantification of β-gal+ cells in the control and mutant brains across rostral to caudal tissue sections shows the decrease in DCN in the mutant. Scale bar in (f) represents 300 μm. CB, cerebellum; MB, midbrain; RL, rhombic lip.