Fig. 7 . p75 upregulation in the SVZ-RMS of NCAM^-/- animals is accompanied by the presence of abnormally mature neurons. (A) Western blot analysis of p75 expression in WT and NCAM^-/- brain. p75 is expressed at higher levels in the RMS-OB of NCAM mutant mice during early postnatal life. ^*, P<0.05 (two-tailed unpaired t-test). (B) Confocal image of sagittal brain slices stained for p75 and doublecortin (DCX) demonstrating the presence of small round p75⁺ DCX^- cells in the WT SVZ-RMS (arrows). p75⁺ cells occasionally form small clusters (insert). (C) Immunolabeling for p75 in NCAM^-/- brains revealed an increased number of p75 cells in the SVZ-RMS. These cells often exhibited a branched morphology (arrowheads). A higher magnification image of the area depicted in the left-hand panel illustrates that most of these p75⁺ cells colocalized with the neuronal marker doublecortin. Scale bars: 20 µm.