PROJECT SUMMARY Socioeconomic status (SES) is associated with executive function (EF) and prefrontal cortex (PFC) development. However, understanding of the specific aspects of SES that influence development of EF and the PFC remains limited. EF in early childhood is associated with initial school readiness, academic success, and a wide range of outcomes in adulthood. Determining how early environmental experiences shape EF development is critical to identify strategies to support the development of these skills to promote healthy outcomes across the life span. Accelerated progress in this effort can be made only when intervention development is informed by a principled and biologically plausible understanding of the developmental mechanisms by which environmental experience shapes the development of the PFC and associated EF. This proposal argues that cognitive stimulation that occurs in the context of caregiver interactions supports development of connectivity between the ventral visual stream (VVS) and the PFC, which lays the groundwork for the complex computations necessary for EF. The proposal will test both environmental (cognitive stimulation) and neurodevelopmental (VVS-PFC connectivity) mechanisms explaining SES-related differences in EF and academic achievement. Study 1 (K99 phase) uses innovative observational methods to assess the home environment of school-attending children aged 6-7 years, cognitive and academic assessments, and functional and structural MRI to examine whether cognitive stimulation is an environmental mechanism explaining SES-related differences in EF (Aim 1). Study 1 will also evaluate whether early cognitive stimulation mediates SES-related differences in structure, function, and connectivity between the VVS and PFC (Aim 2). Study 2 (R00 phase) is a longitudinal study of children 4-5 years (Time 1) followed as they make the important transition to school (Time 2). This study will evaluate whether structure and function of the VVS early in development precedes and predicts structure and function of the PFC (Aim 3) using multimodal neuroimaging techniques (functional near infrared spectroscopy, functional and structural MRI). Finally, Study 2 will test whether cognitive stimulation explains SES-related differences in VVS and PFC structure and function and individual differences in EF, and evaluate whether these pathways ultimately explain disparities in academic achievement (Aim 4). The results of these studies will provide insight into the environmental and neural mechanisms explaining SES-related differences in EF and academic achievement. These studies have the potential to inform interventions to help close the income-achievement gap. This award will provide the candidate, who has a strong background in cognitive neuroscience in adults, with training in developmental methods and developmental cognitive neuroscience to facilitate her transition to an independent research career.