At 16–17 gw, calcarine (Cas) and parietooccipital (Pos) sulci were well defined. At this stage of development, Cas and Pos were folds of the entire hemispheric wall.
Transient zones of the hemispheric wall, histogenesis of the neocortex.
During 15–16 GWs, further ingrowth of fibers into the subventricular zone (SVZ) was revealed and a noticeable increase in the subplate zone (SP) width was identified. The widest zones of the hemispheric wall were subventricular, intermediate (IZ), and subplate zones. Radial and tangential migration paths were traced within these zones. The cortical plate (CP) consisted of dense vertical rows of neuroblasts. The columns of radial neuroblasts migration were clearly visible in the subplate and cortical plate (for more information see Proshchina et al., 2024).
Ganglionic eminence (GE, eminentia ventricularis lateralis)
Average GE width - 1,61 mm, volume - 74,11 mm3 (Proshchina et al., 2024).
Fig. 3-D reconstruction of the ganglionic eminence at gestational week 16
Histogenesis of the subpallial structure
Neostriatum
Total volume of neostriatum 30,57 mm3
Volume of caudate nucleus 9,55 mm3
Volume of putamen 21,02 mm3