Figure 11.

Diffusion tensor imaging illustrates normal brain development during the prenatal period. In embryos as young as 12 days post-fertilization, cellular orientation in the neuroepithelium (NE) can be appreciated (A, blue arrowhead), and 24 hours later, the cortical plate (CP, pink arrowhead) and intermediate zone (IZ, yellow dot) can be distinguished. As development progresses, the cortical plate extends from its original lateral location, rostrally and towards the midline, where neurons are oriented perpendicular to the surface of the brain. The intermediate zone is also developing at this time, with its cellular orientation parallel to the surface of the brain as seen in A. The development of these layers can also be appreciated in the schematic depicted in the box in B. Also shows in B are developmental changes in the thickness of the cortical plate from embryonic day 8 through GD18. Commissural fibers, as shown in C, are readily appreciated by GD17 and include the optic chiasm (white arrowhead), hippocampal commissure (yellow arrowhead), anterior commissure (pink) and corpus callosum (blue arrowhead). Reprinted with permission from J. Zhang et al., Three-dimensional anatomical characterization of the developing mouse brain by diffusion tensor microimaging, NeuroImage, 20(3), 1639-1648. Copyright © 2003, Elsevier.