This movie is an example of axon outgrowth in a WT zebrafish embryo starting at approximately 20 HPF, and visualized by confocal at a rate of 1 stack per minute. There are many  filopodial extensions present, and axons spread widely during outgrowth. Anterior is to the left in this movie.

This movie is an example of axon outgrowth in a KLC4-/- zebrafish embryo starting at approximately 20 HPF, and visualized by confocal at a rate of 1 stack in 1.5 minutes. These axons extend fewer filopodia, tend to grow on top of each other (fasiculate) and show a general bias towards posterior directed growth (anterior is to the left in this movie).