Movie 1.

Self-elongation of the neural tube organoid. The organoids were stained with live cell actin probe to visualize the lumen and the actin in general of the organoids. Part 1, Time-lapse imaging from D0 to D6 showing the self-elongating neural tube organoid formation from a single cell with 10X air objective on Nikon Eclipse Ti inverted microscope. Part 2, Time-lapse imaging between D4 and D6 with 1 hour of interval with 10X air objective on Nikon Eclipse Ti Inverted Microscope. Part 3, Time-lapse imaging between D5 and D6 with 5 min of interval with 60X oil objective on Visitron CSU-W1. Those time-lapses revealed that the neural tube organoid self-elongate and its lumen elongate simultaneously keeping the neural canal-like structure.