Figure 7

Time lapse imaging of Fgf8 ⁺ lineage cells in brain slice culture. Fgf8 ^CreER/+ and Fgf8 ^CreER/neo mice on an mT/mG background exposed to tamoxifen at E8.5. At either E10.5 (panels in rows (A,B)) or E11.5 (panels in rows (C,D)), their brains were removed, sectioned on a vibratome and grown in slice culture [(neurobasal media (NBM)]. Slices were photographed approximately every 12 h, and representative images are shown. Cells in which the reporter had not undergone Cre-mediated recombination are red, recombined cells are green. The brains shown are from litters administered with tamoxifen and dissected in parallel. ‘Rostral’ sections, through the RPC, are in the left panels; ‘caudal’ sections, through the level of containing the MGE, are in the right panels. T0 (i, iv) = onset of culture; T1 (ii, v) = approximately 24 h in culture; T2 (iii, vi) = approximately 48 h in culture. Note that the mutant had widely distributed green cells even at T = 0, and that their distribution did not appear to change during culture.