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. The overarching goal of this proposal is to explore the mature synaptic function of Neuroligin 1 (NL1), a synapse- specific protein implicated in several autism spectrum disorders (ASDs). Molecular biology and mouse genetics will be used together with synaptic physiology to better understand the normal biological function of NL1 and the possible contributions of mutations in this gene to abnormal synaptic function in neuropsychiatric disorders. In addition to providing potential model systems for the study of ASDs, results from this work will contribute significantly to the limited understanding of NL function at mature synapses. In doing so, they may provide new targets for future molecular interventions in psychiatric disorders.