In a striking display of trans-kingdom symbiosis, gut bacteria cooperate with their animal hosts to regulate the development and function of the immune, metabolic and nervous systems through dynamic bidirectional communication along the ‘gut–brain axis’. These processes may affect human health, as certain animal behaviours appear to correlate with the composition of gut bacteria, and disruptions in microbial communities have been implicated in several neurological disorders. Most insights about host–microbiota interactions come from animal models, which represent crucial tools for studying the various pathways linking the gut and the brain. However, there are complexities and manifest limitations inherent in translating complex human disease to reductionist animal models. In this Review, we discuss emerging and exciting evidence of intricate and crucial connections between the gut microbiota and the brain involving multiple biological systems, and possible contributions by the gut microbiota to neurological disorders. Continued advances from this frontier of biomedicine may lead to tangible impacts on human health.

在跨界共生的惊人展示中，肠道细菌与其动物宿主合作，通过沿“肠-脑轴”的动态双向通信来调节免疫、代谢和神经系统的发育和功能。这些过程可能会影响人类健康，因为某些动物行为似乎与肠道细菌的组成有关，并且微生物群落的破坏与几种神经系统疾病有关。大多数关于宿主-微生物群相互作用的见解来自动物模型，它们代表了研究连接肠道和大脑的各种途径的关键工具。然而，将复杂的人类疾病转化为还原论动物模型存在固有的复杂性和明显的局限性。在本次审查中，我们讨论了肠道微生物群与涉及多个生物系统的大脑之间复杂而重要的联系的新兴和令人兴奋的证据，以及肠道微生物群对神经系统疾病的可能贡献。生物医学这一前沿领域的持续进步可能会对人类健康产生切实影响。