Infection during pregnancy increases the risk of neurodevelopmental isorders, such as autism, in offspring. Mouse studies now reveal a link between gut bacteria and typical brain-circuit connections.
Animal studies and epidemiological analysis in humans have shown that if a mother is infected by certain viruses during pregnancy, there is a risk that her offspring will develop autism or other neurodevelopmental disorders. This phenomenon is often studied using a mouse model in which viral infection is mimicked by exposing pregnant animals to a synthetic molecule called poly(I:C) that is structurally similar to doublestranded RNA, a common hallmark of viral infection. This exposure triggers an immune response in the mother that is termed maternal immune activation (MIA), which can lead to atypical social and repetitive behaviours in her offspring. However, the molecular and cellular basis for this phenomenon has remained poorly understood until now.