This is an individual National Research Service Award for post-doctoral research training, which provides support for promising Fellowship Applicants with the potential to become productive, independent investigators in scientific health-related research fields. One of the mechanisms underlying mental health diseases, specifically of schizophrenia and autism, is improper connection between neurons that in turn results in overall abnormal neural circuit function. This project will investigate the role of Lis1 in the regulation of proper formation and elimination of synapses that must be carefully orchestrated throughout development. Current hypotheses regarding autistic behaviors include not only formation of faulty synaptic contacts but also failure to successfully prune synapses once formed or make new connections during childhood development. This project will use molecular methods to assess whether Lis1 plays a prominent role in dendritic filopodia and spine formation and motility that translates into synapse formation and stability. Protein interactors with Lis1 will also be examined, and Lis1 may provide a critical link between external cues and cytoskeletal modulation underpinning activity-dependent synaptic plasticity.