Spinal circuit development Motor neuron circuits in the zebrafish spinal cord support both the rapid evasion response and the leisurely swimming response. Kishore et al. now follow the development of inhibitory interneurons as these circuits are assembled in the larva. Interneurons generated early in development drive different sorts of circuits and synapse onto different subcellular sections of the motor neurons than interneurons generated later in development. Thus, both rapid evasion and slower swimming are supported by the same cellular components assembled in different ways. The authors suggest that development follows an opportunistic rule in which interneurons synapse onto what is available to them at that moment in development. Science, this issue p. 431 Developing spinal inhibitory interneurons form compartmental microcircuits that ensure appropriate patterns of motor output in adult fish. In vertebrates, faster movements involve the orderly recruitment of different types of spinal motor neurons. However, it is not known how premotor inhibitory circuits are organized to ensure alternating motor output at different movement speeds. We found that different types of commissural inhibitory interneurons in zebrafish form compartmental microcircuits during development that align inhibitory strength and recruitment order. Axonal microcircuits develop first and provide the most potent premotor inhibition during the fastest movements, followed by perisomatic microcircuits, and then dendritic microcircuits that provide the weakest inhibition during the slowest movements. The conversion of a temporal sequence of neuronal development into a spatial pattern of inhibitory connections provides an “ontogenotopic” solution to the problem of shaping spinal motor output at different speeds of movement.

中文翻译：

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发育中斑马鱼脊髓运动前抑制的有序区室映射

脊髓回路发育斑马鱼脊髓中的运动神经元回路支持快速逃避反应和悠闲游泳反应。基肖尔等人。现在关注抑制性中间神经元的发展，因为这些回路在幼虫中组装。与发育后期生成的中间神经元相比，在发育早期生成的中间神经元将不同种类的回路和突触驱动到运动神经元的不同亚细胞部分。因此，以不同方式组装的相同细胞成分支持快速逃避和较慢游泳。作者认为，发育遵循一种机会主义规则，其中中间神经元突触到在发育的那一刻对它们可用的东西。科学，这个问题 p。431 发育的脊髓抑制性中间神经元形成隔室微电路，确保成年鱼运动输出的适当模式。在脊椎动物中，更快的运动涉及不同类型脊髓运动神经元的有序募集。然而，尚不清楚运动前抑制电路如何组织以确保不同运动速度下的交替运动输出。我们发现斑马鱼中不同类型的连合抑制中间神经元在发育过程中形成隔室微电路，使抑制强度和募集顺序保持一致。轴突微电路首先发展并在最快的运动中提供最有效的运动前抑制，其次是 perisomatic 微电路，然后是树突状微电路，在最慢的运动中提供最弱的抑制。