Identification of clustering cells. a Western blot from the cortical neurons cultured for 5 days after treatment with vehicle or AF. AF-treated cells showed a significant increase in neural stem or progenitor cell markers such as Nestin, GFAP, and BLBP. *p < 0.05, versus CTL cells (CTL). b The nuclei of cells were stained with Hoechst 33342 (blue). The red circles indicate the clustered cells, which are focally merged with Nestin (green). Scale bar indicates 60 μm. c These pictures represent a magnification of the staining with Nestin. Nestin-positive neural stem or progenitor cells were observed in the clustered cells. Scale bar indicates 60 μm.