Cognitive and affective alterations by prenatal and postnatal stress interaction.

Antenatal maternal stress exposure during pregnancy has been shown to alter the neurodevelopment of fetuses, and consequently affect brain function in offspring after birth. In this study, we investigated the effects of prenatal exposure to social and nonsocial stress on cognitive and affective functions in mice. Pregnant mice were subjected to repeated social defeat stress or restraint stress, and the offspring born from the dams were subjected to a battery of behavioral tests to assess cognitive and affective functions. Heightened anxiety and decreased social interaction with mates were observed in adult mice exposed to prenatal social defeat and restraint stress. In contrast, spatial memory was impaired by prenatal restraint stress, but not social defeat stress. In addition, prenatal stress-induced heighted anxiety and decreased social interactions were still present, whereas spatial memory impairment was not observed, when postnatal chronic stress exposure during the juvenile period was matched with the prenatal stress type (i.e., restraint stress). These results suggest that some neurodevelopmental changes associated with prenatal stress may counteract with postnatal stress-induced alterations. Therefore, prenatal stress-induced neurodevelopmental changes may be understood to be adaptive strategies against anticipated postnatal adverse environments.