Fig. 3

Oligodendrocytes associate with the vasculature in all neocortical layers

(A) Representative single plane confocal images of motor cortex showing collagen-IV labeled vasculature (left, red) and CNPase labeled oligodendrocytes (center, cyan). On the right, four example vOLs from Layer 1, 2, 4 and 6 are displayed at higher magnification and their locations are indicated with arrows and corresponding numbers on the left image. (B) Quantifications reveal that vascular density remains constant throughout the cortex, whereas myelin density increases towards deeper layers. Data were normalized to myelin density in layer 6 (n = 3 mice). (C) Oligodendrocyte cell body density is highly correlated with myelin immunosignal (myelin occupancy), confirming that oligodendrocyte cell body location and density can be used to infer myelination density. Data were fit with a linear function (n = 3 mice). (D) Vasculature (black) from a z-projected cortex volume (same as in A) overlayed with vOL locations (cyan). (E) Plot showing oligodendrocytes occurrence within the volume in D (25 μm bins). Vasculature-associated oligodendrocytes are highlighted in cyan. (F, G) Throughout all neocortical layers, the proportion of vOLs remains constant in the motor cortex (F) and somatosensory cortex (G). Data were tested with a Kruskal-Wallis test and p value is given in the figure (n = 6 mice for layers 1 to 5, and n = 3 mice for layer 6). (H) Random distribution of oligodendrocytes resulted in a lower percentage of vOLs in the same area.