Children whose mothers develop infections during pregnancy are at increased risk for autism, schizophrenia or other neurodevelopmental disorders. However the molecular pathway that leads from infection to autism is unclear. Using an animal model of maternal viral infection, Dr. Patterson have shown that the maternal immune reaction, rather than the virus itself, interferes with fetal development leading to behavioral symptoms of heightened anxiety and decreased social interaction. This experiment will establish which specific immune factors interfere with fetal brain development. Four different immune factors will be tested to produce and then reverse early behavioral deficits in offspring exposed in utero to these immune factors. Any immune factor that meets both criteria will be a leading candidate for continued research into specific molecular pathways that interfere with normal development and lead to autism-like symptoms. What this means for people with autism: This project will use a mouse model of a known risk factor for autism—maternal viral infection—to determine a mechanism that elicits changes in fetal brain development and leads to the autistic phenotype. These findings could lead to a better understanding of what goes wrong in autism, and suggest potential methods of preventing the disorder.