Prader-Willi Syndrome (PWS) is a rare disorder, sharing common genes with autism and schizophrenia; patients with PWS are at a high risk of developing psychiatric illnesses and behavioral problems, however, the underlying neurobiology that places them at-risk is yet unknown. Here we propose a cross-sectional, multi-faceted brain imaging study in 50 children with PWS and 50 age- and gender matched healthy controls (6-25 years old). The aim of this study is to investigate the structural and functional differences between children with PWS and healthy controls, and within the PWS group between children carrying a deletion and those with maternal uniparental disomy. Further, we will investigate the characteristics between prepubertal and adolescent age groups and identify within the PWS group at which age largest deviations possibly take place. The results of the proposed project will shed insights of neurobiology underlying PWS, and will hopefully reveal biomarkers for early intervention and contribute to improving quality of life of the patients as well as their caregivers.