Fig. 4

a Corpus callosum region from mouse brain section labeled by MyL-1, the nucleus were marked by DAPI. b Correspondent 3D-STED image of MyL-1 labeled corpus callosum region displayed by depth coding (thickness ~ 15 μm, STED depletion = 775 nm). c 3D-STED image of selected region showed a myelinic tube structure by depth coding (thickness ~ 5 μm).at unprecedented resolution. d Quantification of MyL-1 labeled myelinic tubular parameters including internal, outside diameter, and wall thickness (n = 10–20 images from three independent experiments)