Abstract Attention deficits cause life-long challenges affecting academic and job performance, social relationships, and life satisfaction. Attention problems typically begin at an early age and children with attention problems struggle in school. Ideally, attention deficits would be identified before a child enters school. A primary limitation in the field is our limited knowledge of the neural signatures of attention in young children. Children with prenatal alcohol exposure (PAE) and children with a diagnosis of fetal alcohol spectrum disorder (FASD) related to PAE experience persistent attention deficits, and PAE is present at birth. Therefore, studying children with and without PAE provides us with an opportunity to examine neural signatures of attention at a young age in a group of children at high risk of attention deficits. Children raised in lower socioeconomic households are also at greater risk of attention problems, and due to high rates of poverty in New Mexico, we are well-positioned to examine its role in attention in children with and without PAE. Research in adults indicates that alpha oscillations play a key role in directing attention, but it is unknown how alpha oscillations are related to attention early in development. Alpha oscillations are easily elicited during rest, modified during tasks, and measurable across development. This study builds on (1) prior research demonstrating thalamus drives some cortical alpha oscillations whereas others are driven by cortico-cortical connections or local network dynamics and (2) studies in preclinical PAE models and research in children with PAE indicating disrupted cortico- thalamic and cortico-cortical tracts with PAE. Aim 1 will establish the role of alpha oscillations and cortico- thalamic or cortico-cortical connectivity in attention by measuring alpha oscillations during rest and task using magnetoencephalography (MEG) and white matter integrity (WMI) using diffusion tensor imaging (DTI) in typically developing children aged 4-7 years. Aim 2 will assess alterations in alpha oscillations and WMI and their relation to attention deficits in children with PAE, relative to typically developing children. Aim 3 will examine the developmental trajectory of alpha oscillations and WMI and their role in attention by following the same children longitudinally until age seven. We hypothesize that alpha oscillations are directly related to WMI and attention in typically developing children. Furthermore, alpha oscillations will be reduced in children with PAE, and these reductions will be related to disruptions in WMI and attention deficits. We expect these effects to be mediated by poverty in both typically developing children and children with PAE. We will test our hypotheses by measuring alpha oscillations using MEG during 3 tasks that robustly manipulate alpha oscillations in parietal cortex, somatomotor regions and the fronto-parietal network and examining how these oscillations relate to ...