NFIX expression at the cortical midline. Expression of NFIX protein at the midline from E15 to adult. Panel A shows that NFIX is strongly expressed in the cingulate cortex and the septum at E15. NFIX is detected in the regions containing the indusium griseum (IGG) and the glia wedge (GW) at E17 (panel B) and in the region containing the subcallosal sling (SS) at E18 (panel C). NFIX was also present at the cortical midline from P0 to adult (D-I) and in the ventricular zone from P7 to adult (arrowheads in F-H). Panel I (higher power of view of the box in H) shows NFIX positive cells in the region of the indusium griseum. Scale bar in D is 70 μm for A; 100 μm for B, C and D. Scale bar in H is 200 μm for panels G and H. Scale bar in I is 30 μm. CiCtx, cingulate cortex; spt; septum; LV, lateral ventricle; IGG, indusium griseum glia; GW, glia wedge; SS, subcallosal sling.