My laboratory studies the neural mechanisms underlying how organisms interact with the environment. Arising from this are parallel interests in circuit formation, particularly of sensory circuits, and neural diseases including autism and Fragile X syndrome (FXS). FXS, which arises from mutations in the RNA-binding protein FMRP, is the leading form of inherited intellectual disability and autism; its study, therefore, provides insights into diseases that afflict large segments of the population. FMRP is expressed in the somatodendritic domain of essentially every neuron. FMRP additionally localizes to axonal ribonucleoprotein particles termed FXGs (Fragile X granules) in a subset of neural circuits, including sensory, motor, and hippocampal circuits. The discovery of FXGs points to a heretofore unknown role for axonal protein synthesis in the vertebrate central nervous system. We are following up on these observations to elucidate how local protein synthesis in the axonal and presynaptic compartments contributes to neural circuit formation and function, and how disruption of this process contributes to the symptoms of diseases including FXS and autism.