美国俄勒冈大学Chris Q. Doe、Sarah D. Ackerman等研究人员合作发现，星形胶质细胞参与运动回路临界期的关闭。该研究于2021年4月7日在线发表于国际一流学术期刊《自然》。

研究人员定义了在发育过程中果蝇运动回路的临界期，并确定了星形胶质细胞对于适当的临界期终止非常重要。在临界期，活动的变化调节了运动神经元的树突长度、复杂性和连通性。在临界期关闭之前，星形胶质细胞侵入神经纤维，而星形胶质细胞的敲除延长了临界期。

最后，研究人员使用了遗传筛选来鉴定关闭临界期的星形胶质细胞-运动神经元信号传导途径，包括Neuroligin-Neurexin信号传导。信号减弱能够使树突状微管不稳定、增加树突动态性和运动行为受损，这强调了临界期关闭的重要性。以前的工作将星形胶质细胞定义为单个突触中可塑性的调节因素。研究人员表明，星形胶质细胞还调节运动回路的临界期关闭，从而确保适当的运动行为。 

据了解，临界期，即可以通过活动修改神经回路的简短间隔，对于正确的神经回路组装是必需的。临界期延长与神经发育障碍有关，但是，确保及时关闭临界期的机制仍然知之甚少。

附：英文原文

Title: Astrocytes close a motor circuit critical period

Author: Sarah D. Ackerman, Nelson A. Perez-Catalan, Marc R. Freeman, Chris Q. Doe

Issue&Volume: 2021-04-07

Abstract: Critical periods—brief intervals during which neural circuits can be modified by activity—are necessary for proper neural circuit assembly. Extended critical periods are associated with neurodevelopmental disorders; however, the mechanisms that ensure timely critical period closure remain poorly understood1,2. Here we define a critical period in a developing Drosophila motor circuit and identify astrocytes as essential for proper critical period termination. During the critical period, changes in activity regulate dendrite length, complexity and connectivity of motor neurons. Astrocytes invaded the neuropil just before critical period closure3, and astrocyte ablation prolonged the critical period. Finally, we used a genetic screen to identify astrocyte–motor neuron signalling pathways that close the critical period, including Neuroligin–Neurexin signalling. Reduced signalling destabilized dendritic microtubules, increased dendrite dynamicity and impaired locomotor behaviour, underscoring the importance of critical period closure. Previous work defined astroglia as regulators of plasticity at individual synapses4; we show here that astrocytes also regulate motor circuit critical period closure to ensure proper locomotor behaviour.

DOI: 10.1038/s41586-021-03441-2

Source: https://www.nature.com/articles/s41586-021-03441-2