Extended Data Figure 1. Alignment of histological sections with in vivo optical images, and identification of V2 stripe types.

(A) In vivo image of the cortical surface vasculature in case MK373 (same case as in Fig. 1) taken under green light illumination. Colored ovals here and in (B-E): outlines of 3 different tracer injection sites. Scale bar: 1mm, valid for all panels. (B) The most superficial histological tissue section cut parallel to the imaging plane and stained for CO, showing the surface vasculature running tangentially to the brain surface. (C) Overlay of the section in (B) and the optical image in (A) demonstrate excellent alignment of superficial blood vessels. Deeper tissue sections containing cell label or CO stripes are aligned to the superficial section using the radial blood vessels. This approach allows for accurate alignment of labeled cells, injection sites and CO compartments in histological sections to the in vivo imaged functional maps. The histological section in (B) was colored red for purpose of illustration. (D) A deeper tissue section stained for CO showing the CO stripes in V2. Thin stripes (Tn) are outlined in white, while thick stripes are outlined in cyan. The same stripe outlines are shown superimposed to the orientation maps in panel (E) and in Fig. 1C–E. Green dots: locations of the CTB488-labeled V1 cells. (E) Difference orientation map (same 22.5°−112.5° map shown in Fig. 1D) with superimposed the CO stripe outlines from (D), the 3 tracer injection sites in V2, and the CTB488-labeled V1 cells (green dots).