Project Summary/Abstract: Research Project (1) Cognitive, Immunological, and Neurophysiological Consequences of Home Radon Exposure in Children and Adolescents The public at large has grown keenly aware of the effects of environmental pollutants and toxins on the developing body. From lead and pesticides to cigarette smoke and industrial air pollution, studies consistently show that environmental toxins have substantial, lasting impacts on the development of youth, including chronic deficits in cognitive and brain development. These consequences can have reverberating impacts on academic achievement and mental health. That said, one surprisingly common, but rarely studied environmental toxin is radon. Radon is a naturally occurring radioactive gas that accumulates in homes and poses significant health risks, including increased risk of developing certain cancers, and damage to developmentally sensitive tissues and organs (e.g., the brain) through accentuated inflammatory processes. The United States (US) Environmental Protection Agency (EPA) set the action limit for home radon concentrations at 4 pCi/L, which is the carcinogenic equivalent of smoking 10 cigarettes per day. An astonishing 1 in 15 homes across the US is expected to have radon concentrations at or above the EPA action limit, leaving a large number of youth across the country chronically exposed to high concentrations of radon. However, studies linking radon toxicity to altered neural and cognitive development are extremely sparse. The current proposal aims to address this critical gap in knowledge by examining the impact of toxic levels of radon exposure on brain and cognitive function in typically-developing youth. Our groundbreaking preliminary work is the first to show that attention (i.e., the ability to direct and maintain focus on specific stimuli and tasks) is uniquely impacted by radon exposure. Specifically, we have found that youth who are chronically-exposed to higher home radon levels had markedly worse performance on behavioral measures of attention, and exhibited altered neural dynamics within the critical brain networks serving attention and higher-order cognition. In the current multimodal neuroimaging study, we will quantify the impact of home radon exposure on multiple distinct attentional systems during child and adolescent development. To this end, we will enroll a large sample of typically-developing youth who will undergo magnetoencephalography (MEG) during a battery of tasks designed to assess multiple unique neural systems serving attentional processing. Youth will also complete structural magnetic resonance imaging (MRI), complete a battery of neuropsychological assessments targeting attentional abilities, and provide saliva samples to capture measures of inflammation that are known to be elevated in the context of radon exposure. Our specific aims are to 1) identify specific attentional domains and neural substrates that are affected by radon exposure, and 2) quantify the mechanistic role of inflammatory processes through which radon alters attentional development in youth. The outcomes of this study have the potential to shape the future of public health policy surrounding radon awareness and mitigation efforts, and this is especially true in the surrounding region where home radon levels are some of the highest in the nation.