When the microbiome hits the nerve

Abstract

Animals have evolved in a world full of microbes and are constantly exposed to different microbiota. Microbes colonize most, if not all, animal epithelia and influence the activity of many organs, including the nervous system. Therefore, any consideration of the development and the function of the nervous system will remain incomplete if the microbiome is not taken into account. Here, we summarize the current knowledge on the Hydra nervous system and, in particular, its role in host-microbiome communication. We show that modern molecular and imaging techniques provide a comprehensive understanding of the performance of such a seemingly simple nervous system in the context of this metaorganism. We propose future work to consider the evolution, function, and development of neural circuits in the context of host-microbiome interactions and present Hydra as a strategic model system with great fundamental and translational relevance to neuroscience.