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Fig. 6.1 (a) NSCs isolated from the embryonic cortex at E12.5 and kept in culture exhibit the
characteristic structure of NEP cells and RGCs. They possess a short and a long process (apical
and basal, respectively, in the tissue). Here, cells are shown at different times in culture, with the
long process becoming more elongated over time, as would happen in the tissue in order to stay
attached to the pial surface. Note a NSC cell that has divided, with the daughter cell remaining in
contact with the basal process. (b) In a microphotograph of a section taken from an E13.5 mouse
embryo and immunostained for the RGC marker BLBP, the three microenvironments to which a
RGC is exposed can be seen: (1) cell bodies are stacked around the ventricle, in the ventricular/
subventricular zones. (2) Basal processes cross the mantle, where immature neurons assume their
final positions and differentiate. (3) The RGC endfeet reach the pial surface. (c) NSCs are able to
produce much of the ECM components of the microenvironment. Here, isolated NSCs from the
E13.5 mouse cortex have been immunostained for nestin (marker of NSCs, in green) and for the
glycoprotein Tenascin-C (in red). (d) NSCs isolated from the embryonic or the adult mouse and rat
brain can be kept in cultures, where they form 3D, free-floating aggregates called neurospheres. (e)
When neurospheres are allowed to attach to a substrate and growth factors are removed from the
medium, many progenitors start to differentiate in neurons (Sox2, marking nueral progenitors is in
green and Dcx, marking immature neurons is in white)
E. Andreopoulou et al.