Movie 2

Migration of Pax2-cells. This movie starts with an overview showing cell motility of Pax2-EGFP positive (green) cells in acute 300 μm thick sagittal slices from lobules IV and V of an 8 day old cerebellum. Rostral is to the right, and dorsal (apical) is towards the top of the frame shown.
In the initial still image, the approximate borders of the white matter (WM) are indicated by white dots. In lobule V, the position of the Purkinje cell layer (PCL) is marked with blue dots, and the inner border of the external granule cell layer (EGL) is indicated by white dashes.
Following this still image, the scene is rotated to give an impression of the three-dimensional arrangement of Pax2-EGFP positive cells. Subsequently, motility of Pax2-cells over a 30 min period is shown. This short sequence is looped over three times. Subsequently, we zoom-in on a region in the more basal part of this lobule (see yellow boxed area in the overview in the top right corner of the movie).
The next sequence again starts with a still image in which the PCL (blue dots) and the inner border of the EGL (white dashed line) are indicated. Three cells marked with red, perpendicular arrowheads will be seen migrating in the subsequent part of the movie. Some immobile cells are labelled with yellow, horizontal arrowheads. The subsequent rotation of the scene shows that the two migratory cells in the inner granule cell layer (here, to the right of the PCL) that appear very close to each other in the standard projection are indeed found at different depth in this slice. Finally, a still image is shown to document how iso-surfaces (labelled whitish-grey), used to calculate the centres of mass of individual Pax2-cells, were fitted to cell volumes. Centres of mass were used to pinpoint cell positions and mobility.
The next sequence shows cell mobility over the complete period of 30 minutes in this region, along with the tracks describing the temporal displacement of the cells. The centres of mass are depicted for every time point as white squares. This scene is replayed three times. Finally, centres of mass and the tracks only are displayed for three loops. Note that the three highly mobile cells in this frame follow more-or-less straight tracks towards the EGL. In the final still image, tracks of the mobile cells marked by red arrowheads are again labelled by red, perpendicular arrowheads. Note that centres of mass of immobile cells (yellow, horizontal arrowheads) did not move appreciably. Colour coding of the tracks reflects time (scale in the bottom right corner of the movie).