Movie 2.

Twenty-four-hour time-lapse recording of dI1 axons crossing the floor plate in cultured intact spinal cords. dI1 neurons were visualized by in ovo electroporation of the Math1::tdTomato-F plasmid (shown in magenta). In the control condition, dI1 axons turned rostrally in a well-organized manner after exiting the floor plate. However, knockdown of Cables1 induced aberrant phenotypes at the floor-plate exit site with axons turning caudally (yellow arrow) or having problems to extend rostrally (yellow arrowhead). These aberrant phenotypes clearly induced the formation of a disorganized ventral axon bundle as shown by all commissural axons expressing EGFP-F (green) compared to the tightly organized control funiculus (white arrows). R, rostral; C, caudal.