Figure 5.

Brain toluidine blue sections, postconceptional weeks (PCW) 12–15. (A). Frontal region with a dominant radial organization, fibers in horizontal and vertical orientation (long arrows), and small blood vessels occupied by erythroblasts can be identified (arrowhead). (B). Close-up with fibers oriented in horizontal and vertical directions along cells with diverse nuclei shapes (short and open arrows) interspersed by cells with long processes (long arrow) and blood vessels occupied by erythroblasts (arrowheads). (C). Primitive glial cells can be identified along with small vessels (arrowhead). (D). Slender cells with long processes and vesicular nuclei streaming (arrowheads) in the primitive cortex. (E). Neuronal bodies and numerous capillaries with luminal erythroblasts areidentified. Insert shows three erythroblasts in different stages of development; the orthochromatic cell is marked with a short black arrow between two basophilic cells marked with white arrows.