Project Summary Neighborhoods are an important ecological context for child and adolescent development and a social determinant of physical health, mental health, and school achievement. Research has begun to elucidate the associations between neighborhood characteristics and brain structure, function, and behavior in relation to executive function (EF) emotion regulation (ER), and emotional processing which may contribute to these short- and long- term differences in health and development. Nevertheless, there are no population-based studies that have examined the relation between neighborhood characteristics, and changes in neighborhood characteristics, with longitudinal changes in neurodevelopment to determine if differences widen, narrow, or remain stable during adolescence, a potential sensitive period. Moreover, there has been limited consideration of how associations may vary across the country. In addition, neighborhood characteristics may increase vulnerability to major stressors and changes in schooling, such as the changes that occurred in youth’s experiences during a public health disruption. These multi-dimensional changes in youth environments, stress, and schooling may exacerbate neighborhood-related differences in neurodevelopmental systems. Finally, it is important to understand resilience and the modifiable contextual factors that may protect against both neighborhood characteristics and the impact of changes in youth environments, stress, and schooling. This proposal will use the Adolescent Brain and Cognitive Development (ABCD) Study to address these questions. The ABCD Study enrolled 9-10-year-olds (n = 11,878) across 21 U.S. sites, contains multimodal measures of neurodevelopment for EF, ER, and emotional processing and rich measures of family, school, and neighborhood contexts, as well rapid measurement of the impact of a public health disruption on experiences. This study will capitalize on the staggered timing of the onset of a public health disruption in the ABCD cohort, which occurred between varying waves of data collection across participants. This creates a quasi-experimental design with the study separated into a pre-disruption and post-disruption onset phase. We will determine the association between neighborhood characteristics, and neighborhood change, and longitudinal change in brain and behavioral development, prior to a disruption (Aim 1). Second, we will examine if multi-dimensional change in youth environments, stress, and schooling overall during a public health disruption, as well as specific changes, exacerbate neighborhood related differences, with pre-disruption measures serving as controls for post-disruption measures. (Aim 2). Finally, we will elucidate the modifiable family, community and school factors that serve as moderators and foster resilience (Aim 3). This study will thus identify potential neurodevelopmental pathways related to neighborhood characteristics and changes in youth environments,...