Robust sex differences in baseline adult neurogenesis in the dentate gyrus have not been reported, although estrous cycle differences exist in female rats (Tanapat et al., 1999), but not in female mice (Lagace et al., 2007). However, females and males may differ in how adult neurogenesis is affected by stressful experiences. The reduction in cell proliferation in adult male rats after fox odor exposure is not seen with female rats (Falconer & Galea, 2003). Male rats show decreases in the survival of new neurons following chronic electric shock, but female rats show increases in the survival of new neurons following chronic electric shock (Westenbroek et al., 2004). These results only appear during periods of social isolation. When rats are group-housed, the differences disappear between males and females. Prenatal stress can affect baseline neurogenesis rates when pups mature to adulthood. Male rats that were stressed prenatally have suppressed baseline survival of new neurons, while there is no change in female rats that were stressed prenatally (Zuena et al., 2008). Early weaning results in greater suppression of cell proliferation and survival of
