Figure 4.

DiI-labeled granule cell migration in the molecular layer of P8 cerebellar slices. Digital images of DiI fluorescently labeled migrating granule neurons in P8 cerebellar slices from tPA^+/+ or tPA^−/− mice were collected every 20–30 min. (Left) The two labeled cells (arrowheads) in the tPA^+/+ molecular layer are migrating inward along radial processes toward a stationary DiI fragment and away from the pial surface (whose direction is indicated by the arrow) at rates of 11 μm/h for the upper cell and 15 μm/h for the lower cell. (Right) Granule neurons (arrowheads) in the tPA^−/− molecular layer show slower rates of inward migration along radial processes (2.3 μm/h for the upper cell and 3.6 μm/h for the lower cell) relative to a stationary cell (∧). (Bar = 7 μm.)