Cytoarchitectural dynamics of neural rosettes reflects changes in NSC capabilities during cortical development.

E-RG rosettes (top panel) correspond to early cortical radial glial cells (NSCs; green colored) that hold strong epithelial characteristics and hence organize in a radial manner with apical sites adjoining at rosette lumens—similarly to the ventricular zone of the developing cortex. M-RG rosettes (bottom) are characterized by decreased numbers of epithelial radial glial cells and elevated number of neurons (blue colored) and intermediate progenitors (red colored), which are both non-epithelial—hence decreasing rosette epithelial integrity and eventually lead to rosette disassembly at later stages. Both E-RG and M-RG rosettes perform INM—the hallmark of cortical radial glial development. INM of E-RG rosettes is characterized by basal (blue phase, right) and apical (red phase, right) motions that are faster (higher frequency of blue and red phases) and more radially organized (less twisted pattern of blue and red phases), compared to M-RG rosettes. However, for all rosettes regardless of developmental stage (top or bottom panels), basal motions (blue) are always slower yet more organized than apical motions (red). The enhanced radial organization of E-RG rosettes can be explained by enhanced radial organization of basal motions as well as inherent mechanism that increases both basal and apical motions, possibly due to the strong confining structure and high NSC abundance within E-RG rosettes. B→A, basal to apical; A→B, apical to basal.