Prenatal and postnatal animal models of immune activation: relevance to a range of neurodevelopmental disorders

Epidemiological evidence has established links between immune activation during the prenatal or early postnatal period and increased risk of developing a range of neurodevelopment disorders in later life. Animal models have been used to great effect to explore the ramifications of immune activation during gestation and neonatal life. A range of behavioral, neurochemical, molecular, and structural outcome measures associated with schizophrenia, autism, cerebral palsy, and epilepsy have been assessed in models of prenatal and postnatal immune activation. However, the epidemiology-driven disease-first approach taken by some studies can be limiting and, despite the wealth of data, there is a lack of consensus in the literature as to the specific dose, timing, and nature of the immunogen that results in replicable and reproducible changes related to a single disease phenotype. In this review, we highlight a number of similarities and differences in models of prenatal and postnatal immune activation currently being used to investigate the origins of schizophrenia, autism, cerebral palsy, epilepsy, and Parkinson's disease. However, we describe a lack of synthesis not only between but also within disease-specific models. Our inability to compare the equivalency dose of immunogen used is identified as a significant yet easily remedied problem. We ask whether early life exposure to infection should be described as a disease-specific or general vulnerability factor for neurodevelopmental disorders and discuss the implications that either classification has on the design, strengths and limitations of future experiments.