Fig. 7
Analysis of the role of axons in lateral cell movement. a Images extracted from a movie performed on an embryo expressing mosaic ngn1:gfp after laser ablation of an axon. Cell tracks are represented in magenta for the cell with the ablated axon and in white for three neighbouring cells. Magenta arrowheads point to the tip of the ablated axon during its regrowth towards the brain surface. b, c Direction of movements and MSD analysis for the cells with ablated axons as compared with neighbouring cells, during the period of time that preceeds the formation of the new axon/brain contact. d Images extracted from a movie performed on an embryo expressing mosaic ngn1:gfp and treated with colcemid from 12 s onwards. Yellow tracks show the convergence of two anterior cells, and magenta tracks show the lateral movements of round, axonless cells. e, f Direction of movements and MSD analysis for lateral movements of the round axonless central cells, as compared with wild-type untreated central cells. Scale bars: 20 µm