Movie S7.

Cortical slices prepared at E18.5 from NexCre/+ mouse embryos subjected to in utero electroporation at E15.5 with a Cre-dependent expression plasmid for GFP were monitored every 12 min for 13 h 36 min with a confocal microscope to follow the migration of GFP+ cells. The brain surface is on the upper left.