planes clearly capturing somas were used, and migrating speed was calculated as follow: speed=distance of soma translocation (mm)/[(F2-F1)×10 (min) [, in which F2 and F1 represented the frame number after and before soma translocation happened. % of migrating neurons was calculated by dividing the number of translocating somas by total soma numbers within the focus plane. The ratio of active growth cone was calculated by dividing numbers of forward moving growth cones by total soma numbers within the focus plane.
