Autism is characterized by errors in the formation of connections between neurons. During brain development, neurons born in one area of the brain often must migrate to their final destination. Because abnormal migration of neurons can cause abnormal connections to be formed between neurons, migration defects could be an underlying cause of autism. Genes that are involved in the control of migration are therefore potential candidates for involvement in autism. One such gene is brain-derived neurotrophic factor (BDNF), which has been found to be expressed at increased levels in autistic patients. BDNF signals to migrating neurons to control the direction of their migration. In this study, Dr. Zhao and colleagues will study the role of BDNF in neuronal migration in further detail. Using genetic and molecular techniques, researchers will identify the molecules that control how and where in the brain BDNF is produced and secreted. Various candidate genes and molecular pathways will be tested for their involvement in this process. Determining how BDNF expression and localization is regulated will provide insight into its effects on controlling neuronal migration. This research will help to further define the genes and molecules involved in autism, and may provide new paths towards therapeutic approaches in the treating autism.