Growth cones and actin waves share important structural similarities. (A–D) Distribution of F-actin cytoskeleton of growth cones (A and B) and actin waves (C and D) of DIV2 cortical neurons visualized by SIM (A and C) and platinum replica EM (B and D). Boxed regions in B and D are enlarged in the right panel. Bars: (A–D, left) 2 µm; (B and D, right) 1 µm.