Differential effects of early or late exposure to prenatal maternal immune activation on mouse embryonic neurodevelopment.
Guma E., Bordeleau M., González Ibáñez F., Picard K., Snook E., Desrosiers-Grégoire G., Spring S., Lerch JP., Nieman BJ., Devenyi GA., Tremblay M-E., Chakravarty MM.
SignificancePrenatal exposure to maternal infection increases the risk of developing mental health disorders, such as schizophrenia and autism spectrum disorder. Exposure to maternal immune activation has been associated with a number of neuroanatomical deficits in adolescent and adult offspring, with differing effects based on the gestational timing of infection. However, little is known about how the embryo brain is affected. We show, using whole-brain MRI, that maternal immune activation significantly affects brain anatomy. When the exposure occurs early in pregnancy, volume reductions are mainly observed, while the opposite is true for exposure later in pregnancy. Furthermore, we identify alterations to the density of certain classes of neurons and glia, which have been associated with stress and inflammation in the brain.