We explore interactions between the nervous and immune systems, and how these interactions influence complex behavior such as cognition and emotion. Far beyond its role in host defense, there is mounting evidence for the vital role the immune system plays within the brain, in both normal, “homeostatic” processes (e.g., sleep, metabolism), as well as in pathology, when the dysregulation of immune molecules may occur. The developing brain in particular is exquisitely sensitive to both endogenous and exogenous signals, and increasing evidence suggests the immune system has a critical role in brain development and associated behavioral outcomes for the life of the individual. Notably, evidence from both animal and human studies implicates the immune system in a number of disorders with known or suspected developmental origins, including schizophrenia, anxiety/depression, and autism. Thus, the proximate goal of my research program is to determine how seemingly disparate challenges during the perinatal period of life, such as infection, stressors, or toxins, may converge on the immune system and thereby markedly influence brain development, as well as cognitive and affective behaviors throughout the remainder of the lifespan. Conversely, we are also exploring how interventions, such as nurturing maternal care or environmental enrichment, can work to counteract the deleterious effects of early-life infection, trauma, or stress, again via their impact on neuroimmune communication.