Associate Professor of Pediatrics and Program in Neuroscience
Harvard Medical School
We are particularly interested in the role of immune molecules in both normal and disrupted brain development, based on evidence from human and animal studies that immune system dysfunction or inflammation may be critical in a number of neurodevelopmental disorders, including schizophrenia, cognitive and mood disorders, and autism. A focus is on the resident immune cells of the brain, microglia, including their development and function in response to early life inflammatory signals. I developed a model of neonatal bacterial infection during my post-doc and early years as an assistant professor that demonstrated that neonatal infection leads to lifelong vulnerability to cognitive disruption, via specific, enduring changes in microglial function (Bilbo et al., J Neurosci, 2005; Williamson et al., J Neurosci, 2011). Based on these results I have argued that the early life environment of an individual is especially critical in shaping the way that microglia and hence the brain develop, with significant consequences for brain and behavior throughout the remainder of the lifespan. I further hypothesized this model would provide a reference for the understanding of a potentially wide range of environmental factors that impact the developing immune system, such as social and environmental toxins, diet, drugs of abuse, and others, which thereby enduringly alters neuroendocrine function, including the risk of disorders such as autism. We now have strong evidence that this is the case. A greater understanding of the specific mechanisms underlying the role of the immune system in neural development will allow researchers and medical professionals to expand their current view of immune molecules, traditionally considered important only during sickness, to a broader role for these fascinating molecules in many basic physiological processes.