PROJECT SUMMARY / ABSTRACT Fetal alcohol spectrum disorders (FASDs) comprise a range of effects resulting from prenatal alcohol exposure (PAE) including neurological abnormalities, cognitive and behavioral impairments, growth retardation, and craniofacial anomalies. Few treatments have been investigated despite FASD’s tremendous public health burden. Cognitive deficits are a core feature of FASD, and cognition is a natural target for intervention. One potential intervention for cognition in FASD is the essential nutrient choline - known to have effects on brain development and cognition. In the hippocampus, choline contributes to increased dendritic arborization, larger cells, and functional changes. Choline affects the cholinergic system and alters brain structure and function in regions essential for memory functioning, including methylation in the hippocampus and prefrontal cortex. Only a handful of human choline studies for FASD have been undertaken and our group has conducted most of them. Our early double-blind, randomized, controlled trial established safety and tolerability. Our subsequent trial revealed beneficial effects for sequential delayed memory in participants with FASD (greater in younger [ages 2-3] rather than older [ages 3-5] children). Our third (ongoing) study included a long- term follow-up that demonstrated long-term benefits for choline vs. placebo in non-verbal processing, working memory, long-term verbal memory, and ADHD behavior. The proposed studies will include a new clinical trial with a new cohort of 2-5 year old children with FASD. Rather than a placebo- controlled trial, it will be a two-arm block-randomized study with cumulative choline exposure durations of 3 or 6 months. Results will directly inform future clinical implementation of choline as a neurodevelopmental intervention. The proposed studies will also capitalize on three existing cohorts for additional longitudinal studies that will determine durability of effects from early treatment. A 4- year and 8-year follow-up study will each examine cognitive effects as well as structural and functional brain effects using advanced MRI methods. Cognitive measures will include the Stanford- Binet Intelligence Scale, the Elicited Imitation memory test, the NIH Toolbox Flanker test and Picture Sequence Memory Test, and the Minnesota Executive Function Scale. We will examine choline effects on behavior using parent-report (CBCL) and a structured diagnostic interview (KSADS). Select hippocampal sub-fields will be examined for volumetric improvements following choline or placebo. Functional connectivity will be examined and is expected to reflect changes from early choline supplementation. We will also use cortical myelin mapping to evaluate choline’s effect on long-term myelin development. In addition, we will apply diffusion-weighted imaging to determine choline’s effect on white matter microstructure – which is known to be disrupted in FASD.