microRNAs and noncoding RNAs are potent regulators of gene expression and are enriched in the nervous system. Their diversity and abundance, dramatically increased in human brain, may contribute to advanced complexity of neuronal circuits and behavior. microRNA dysfunction is implicated in psychiatric disorders; however, the underlying mechanisms are poorly understood. I use genetic, viral, molecular, and behavioral approaches to target specific microRNAs in mice and explore their functions in vivo. My projects currently focus on (1) the regulation of Purkinje cell gene expression, activity, and downstream behaviors by schizophrenia- and autism- associated cerebellar microRNAs and (2) the regulation of cocaine-seeking behavior and anxiety-related behaviors by activity-dependent microRNAs.