endogenous marker of the cell cycle, Ki67 (Gerdes et al. 1984) on adjacent sections. Every twelfth section/animal (each section 480 μm apart) was kept for DCX immunohistochemistry to detect newly differentiated neurons (Brown et al. 2003; Gleeson et al. 1999; Rao & Shetty, 2004), and immunohistochemistry for the high mobility group transcription factor SOX2, to label neuronal stem cells. SOX2 expression is largely restricted to neural stem cells, is known to be expressed within neural progenitors throughout adulthood (Brazel et al. 2005) and is necessary for neural stem cell maintenance and survival (Episkopou, 2005). SOX2 may be expressed in GFAP-positive astroglia ; however, the majority of SVZ progenitors are negative for GFAP (Komitova & Eriksson, 2004).
