A–E, Histograms of soma length (A), soma width (B), leading process length (C), movement rate(D), and movement direction (E) of granule cells in the EGL. To categorize the morphology and behavior of the postmitotic granule cells within the EGL, we divided the width of the EGL of the P10 mouse into five levels:levels I, II (proliferating cell layer; within 12 μm of the pial surface); level III(postmitotic cell layer; within 18 μm of the pial surface);level IV (postmitotic cell layer; within 24 μm of the pial surface); and level V (postmitotic cell layer; over 24 μm from the pial surface). Each column represents the average values obtained from 80 migrating granule cells in level III, 75 cells in level IV, and 64 cells in level V. *p < 0.05 and **p < 0.01 indicate statistical significance.