Gut microbiota has been linked to infant neurodevelopment. Here, an association between infant composite cognition and gut microbiota composition is established as soon as 6 months. Higher diversity and evenness characterize microbial communities of infants with composite cognition above (Inf-aboveCC) versus below (Inf-belowCC) median values. Metaproteomic and metabolomic analyses establish an association between microbial histidine ammonia lyase and infant histidine metabolome with cognition. Fecal transplantation from Inf-aboveCC versus Inf-belowCC donors into germ-free mice shows that memory, assessed by a novel object recognition test, is a transmissible trait. Furthermore, Inf-aboveCC mice are enriched in species belonging to Phocaeicola, as well as Bacteroides and Bifidobacterium, previously linked to cognition. Finally, Inf-aboveCC mice show lower fecal histidine and urocanate:histidine and urocanate:glutamate ratios in the perirhinal cortex compared to Inf-belowCC mice. Overall, these findings reveal a causative role of gut microbiota on infant cognition, pointing at the modulation of histidine metabolite levels as a potential underlying mechanism.

肠道微生物群与婴儿神经发育有关。在此，婴儿复合认知与肠道微生物群组成之间的关联最早在 6 个月时就建立了。综合认知高于（Inf-aboveCC）与低于（Inf-belowCC）中值的婴儿的微生物群落具有较高的多样性和均匀性。宏蛋白质组学和代谢组学分析建立了微生物组氨酸氨裂解酶和婴儿组氨酸代谢组与认知之间的关联。 Inf-aboveCC 与 Inf-belowCC 供体的粪便移植到无菌小鼠体内表明，通过新的物体识别测试评估的记忆是一种可遗传的特征。此外，Inf-aboveCC 小鼠富含 Phocaeicola 物种，以及先前与认知相关的拟杆菌属和双歧杆菌属。最后，与 Inf-belowCC 小鼠相比，Inf-aboveCC 小鼠在鼻周皮质中表现出较低的粪便组氨酸和尿刊酸：组氨酸和尿刊酸：谷氨酸比率。总的来说，这些发现揭示了肠道微生物群对婴儿认知的因果作用，指出组氨酸代谢物水平的调节是潜在的潜在机制。