The gut microbiota is a vast, complex, and fascinating ecosystem of microorganisms that resides in the human gastrointestinal tract. As an integral part of the microbiota-gut-brain axis, it is now being recognized that the microbiota is a modulator of brain and behavior, across species. Intriguingly, periods of change in the microbiota coincide with the development of other body systems and particularly the brain. We hypothesize that these times of parallel development are biologically relevant, corresponding to 'sensitive periods' or 'critical windows' in the development of the microbiota-gut-brain axis. Specifically, signals from the microbiota during these periods are hypothesized to be crucial for establishing appropriate communication along the axis throughout the life span. In other words, the microbiota is hypothesized to act like an expected input to calibrate the development of the microbiota-gut-brain axis. The absence or disruption of the microbiota during specific developmental windows would therefore be expected to have a disproportionate effect on specific functions or potentially for regulation of the system as a whole. Evidence for microbial modulation of neurocognitive development and neurodevelopmental risk is discussed in light of this hypothesis, finishing with a focus on the challenges that lay ahead for the future study of the microbiota-gut-brain axis during development.

中文翻译：

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年度研究回顾：关键窗口——神经认知发育中的微生物群-肠-脑轴。

肠道微生物群是一个庞大、复杂且迷人的微生物生态系统，存在于人类胃肠道中。作为微生物群-肠-脑轴的一个组成部分，现在人们认识到微生物群是跨物种的大脑和行为的调节剂。有趣的是，微生物群的变化时期与其他身体系统，尤其是大脑的发育相吻合。我们假设这些平行发展的时间在生物学上是相关的，对应于微生物群-肠-脑轴发育的“敏感期”或“关键窗口”。具体而言，假设这些时期来自微生物群的信号对于在整个生命周期中沿轴建立适当的通信至关重要。换句话说，假设微生物群充当预期输入，以校准微生物群-肠-脑轴的发育。因此，预计在特定发育窗口期间微生物群的缺失或破坏将对特定功能或整个系统的调节产生不成比例的影响。根据这一假设讨论了微生物调节神经认知发育和神经发育风险的证据，最后重点关注发育过程中微生物群 - 肠 - 脑轴的未来研究面临的挑战。因此，预计在特定发育窗口期间微生物群的缺失或破坏将对特定功能或整个系统的调节产生不成比例的影响。根据这一假设讨论了微生物调节神经认知发育和神经发育风险的证据，最后重点关注发育过程中微生物群 - 肠 - 脑轴的未来研究面临的挑战。因此，预计在特定发育窗口期间微生物群的缺失或破坏将对特定功能或整个系统的调节产生不成比例的影响。根据这一假设讨论了微生物调节神经认知发育和神经发育风险的证据，最后重点关注发育过程中微生物群 - 肠 - 脑轴的未来研究面临的挑战。