There is increasing evidence that bidirectional interactions between the microbiome and nerves play a normal physiological role in the adult nervous system. Evidence also suggest that perturbation of the microbiome may be involved in a wide variety of nervous system pathologies. The development of the nervous system and the maturation of the microbiome occur in parallel, however there are few studies that have examined the role of the microbiome in nervous system development. This project will use a germ free zebrafish model to investigate how the microbiome influences neuronal development and whether manipulation of microbiotal composition can ameliorate neurodevelopmental abnormalities.