瑞士洛桑联邦理工学院Pavan Ramdya小组发现，下行网络将指令信号转化为群体动机控制。该研究于2024年6月5日在线发表于国际一流学术期刊《自然》。

研究人员发现果蝇的指令样神经元能直接招募额外的指令样神经元网络来协调需要主动控制多个身体部位的行为。具体来说，研究人员发现，以前认为单独驱动行为的指令样下行神经元（DN）事实上共同激活了更大的DN群体。连接组分析和实验操作显示，这种功能性招募可以通过指令样DN与大脑中相互连接的DN网络之间的直接兴奋连接来解释。

下行群体招募是行为控制的必要条件：具有许多下游下行伙伴的DN需要网络共同激活才能驱动完整的行为，如果没有它们，则只能驱动简单的刻板动作。这些DN网络位于行为特异性集群中，相互抑制。这些结果支持一种类似指令的下行控制机制，在这种机制中，行为是通过招募越来越大的DN网络产生的，这些DN网络通过结合多个运动亚程序来组成行为。

研究人员表示，要将意图转化为行动，运动指令必须通过DN从大脑传递到下游运动回路。这些神经元包括一小组足以驱动行为的指令样神经元，其回路机制尚不清楚。

附：英文原文

Title: Descending networks transform command signals into population motor control

Author: Braun, Jonas, Hurtak, Femke, Wang-Chen, Sibo, Ramdya, Pavan

Issue&Volume: 2024-06-05

Abstract: To convert intentions into actions, movement instructions must pass from the brain to downstream motor circuits through descending neurons (DNs). These include small sets of command-like neurons that are sufficient to drive behaviours1—the circuit mechanisms for which remain unclear. Here we show that command-like DNs in Drosophila directly recruit networks of additional DNs to orchestrate behaviours that require the active control of numerous body parts. Specifically, we found that command-like DNs previously thought to drive behaviours alone2,3,4 in fact co-activate larger populations of DNs. Connectome analyses and experimental manipulations revealed that this functional recruitment can be explained by direct excitatory connections between command-like DNs and networks of interconnected DNs in the brain. Descending population recruitment is necessary for behavioural control: DNs with many downstream descending partners require network co-activation to drive complete behaviours and drive only simple stereotyped movements in their absence. These DN networks reside within behaviour-specific clusters that inhibit one another. These results support a mechanism for command-like descending control in which behaviours are generated through the recruitment of increasingly large DN networks that compose behaviours by combining multiple motor subroutines.

DOI: 10.1038/s41586-024-07523-9

Source: https://www.nature.com/articles/s41586-024-07523-9