Studies over the last decade have transformed our previously simplistic view of microbes, having only a pathogenic role in disease to a more robust understanding that they are critical for maintaining human health. Indeed, our microbiota-the collection of commensal organisms that live in and on each of us-contributes to nearly every facet of host physiology, from ontogeny of the immune system to neurological function to metabolism. Although the specific details of these host-microbe interactions are still being elucidated for most diseases, the coupling of clinical samples with animal models of disease have provided key insights. This review provides some general background on the microbiota, highlights a few examples of how the microbiota influences diseases of the central nervous system, and provides a perspective for how these findings may be clinically translatable.
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