小柯机器人

近日，瑞士巴塞尔大学Silvia Arber及其小组绘制出脑干回路内各种前肢动作的功能图谱。该项研究成果于2021年1月6日在线发表在《自然》杂志上。

研究人员定义了功能图谱的逻辑，这被用于脑干外侧头端延髓（latRM）内的熟练前肢运动。通过在自由移动的小鼠中使用体内电生理学，研究人员揭示了将latRM群体调整为独特前肢动作的神经元代码。这些包括获取和食物处理，这两者都会因兴奋性latRM神经元的扰动而受损。通过遗传学和病毒示踪的组合使用，研究人员证明了兴奋性latRM神经元通过轴突靶标分离成不同的群体，并通过脑干和脊髓回路的差异募集起作用。

通过调查投射分层latRM群体的行为潜能，研究人员发现这些群体的光遗传学刺激可以引起多种前肢运动，并且每种行为均由单个小鼠稳定表现。总而言之，投射分层的脑干群体编码动作阶段，并共同作为调节复杂前肢运动关键特征的潜在基础，从而鉴定出熟练前肢行为的脑干底物。

据悉，脑干是控制身体运动的关键中心。虽然人们已经知道对全身运动至关重要的脑干细胞类型和回路的确切性质，但是了解熟练前肢运动神经元基础的工作主要集中在上脑干中心和脊髓。

附：英文原文

Title: A functional map for diverse forelimb actions within brainstem circuitry

Author: Ludwig Ruder, Riccardo Schina, Harsh Kanodia, Sara Valencia-Garcia, Chiara Pivetta, Silvia Arber

Issue&Volume: 2021-01-06

Abstract: The brainstem is a key centre in the control of body movements. Although the precise nature of brainstem cell types and circuits that are central to full-body locomotion are becoming known1,2,3,4,5, efforts to understand the neuronal underpinnings of skilled forelimb movements have focused predominantly on supra-brainstem centres and the spinal cord6,7,8,9,10,11,12. Here we define the logic of a functional map for skilled forelimb movements within the lateral rostral medulla (latRM) of the brainstem. Using in vivo electrophysiology in freely moving mice, we reveal a neuronal code with tuning of latRM populations to distinct forelimb actions. These include reaching and food handling, both of which are impaired by perturbation of excitatory latRM neurons. Through the combinatorial use of genetics and viral tracing, we demonstrate that excitatory latRM neurons segregate into distinct populations by axonal target, and act through the differential recruitment of intra-brainstem and spinal circuits. Investigating the behavioural potential of projection-stratified latRM populations, we find that the optogenetic stimulation of these populations can elicit diverse forelimb movements, with each behaviour stably expressed by individual mice. In summary, projection-stratified brainstem populations encode action phases and together serve as putative building blocks for regulating key features of complex forelimb movements, identifying substrates of the brainstem for skilled forelimb behaviours.

DOI: 10.1038/s41586-020-03080-z

Source: https://www.nature.com/articles/s41586-020-03080-z

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