Movie 1, related to Figure 2.

Cells in the sensory epithelium of cochlear explants move toward apex.
Low magnification time-lapse of a full Z-stack projection from an Atoh1^Cre*PR; R26R^tdTomato cochlear explant established at E13 and imaged for 15 hours beginning at 2 DIV (E15 equivalent). Lengthening and slight narrowing of the population of labeled cells is apparent as cells move in the apical direction. Images were captured at 6 min. intervals.