Fig. 3: In vivo reflectance images of a mouse brain down to cortical layer 4 through an intact skull.

a 3D-rendered through-skull image. The SHG images were used to visualize the mouse skull (colored in green). The depth-dependent intensity was plotted to estimate the skull thickness (inset). The depth of the dura matter was set as z = 0 μm. Cortical layer 1 (up to ~100 μm) and cortical layer 4 (400–650 μm) were mainly imaged since the myelinated axons are distributed laterally at these layers. Color bar: depth. b Conventional OCM images at representative depths displayed with gray-dotted boxes in a. Scale bar: 40 μm. c Aberration-corrected images at the same depths as those shown in b. Individual images are MIPs in the depth ranges of 41–56, 443–470, 515–539, and 548–578 μm. Each image was normalized by its maximum intensity. Color bar: normalized intensity. d Aberration maps of the subregions in c. Color bar: phase in radians. The aberration maps represent the spatial phase retardation at the plane conjugate to the skull. Only the output aberration maps are shown here, and the associated input aberrations are shown in Supplementary Fig. 4. Scale bars: 800 μm. Note that the diameter of the aberration map increases with depth due to illumination/detection geometry (Supplementary section 1.6).