Ar-turmerone induces neurogenesis in vitro and in vivo. (A) NSCs were allowed to differentiate in the absence (control) or presence of 6.25 μg/ml ar-turmerone. Immunocytochemistry 10 days after growth-factor discontinuation revealed fewer undifferentiated (SOX2+) NSCs in the turmerone-treated group, but more young neurons. The generation of astrocytes and oligodendrocytes was not affected by ar-turmerone (mean ± SEM; **P < 0.01, compared with control). (B) Representative images of differentiated cells include CNPase-positive oligodendrocytes (left), TuJ1-positive young neurons (middle), and GFAP-positive astrocytes (right); bar represents 50 μm. (C) After i.c.v. injection of 3 mg (1 mg/μl) ar-turmerone, significantly more DCX-positive neuroblasts were observed in the SVZ compared with placebo-injected control animals (mean ± SEM; **P < 0.01). (D) Representative staining of DCX-positive neuroblasts in the SVZ (bar represents 50 μm).