Nature2014-06-19 1:01 PM

控制精确动作的脑干回路 Brainstem nucleus MdV mediates skilled forelimb motor tasks

论文摘要 
 
本期发表的两篇论文探讨了哺乳动物运动控制中一个长期未解之谜——脑和脊髓之间控制运动(如伸手的动作)的回路的组织和功能。Thomas Jessell及同事对一类小鼠脊髓中间神经元进行了研究,这类神经元在其他物种中已知涉及前肢的精细动作。他们发现,在小鼠中,这些神经元有适当的解剖“神经支配”来承载运动命令和一个内部拷贝信号,这些神经元的切除会削弱伸手的动作。而且,“升支”的光遗传激活会招来一个小脑回路,还会破坏伸手的动作。这些发现表明,这些神经元是在伸手过程中对运动输出进行快速更新的一个内部拷贝通道的构成部分。Silvia Arber及同事将病毒跟踪和遗传学方法相结合,对从小鼠脑干向控制肢体运动的运动神经元的神经元投射的多样性进行了定性。他们发现,尤其是一个被称为“ventral medullary reticular formation”(或MdV)的区域,在功能上是专门用于前肢运动控制的。这里的神经元专门以前肢神经元为目标,在执行运动任务过程中被招来,使这些神经元失活会影响精细动作。

Abstract 

Translating the behavioural output of the nervous system into movement involves interaction between brain and spinal cord. The brainstem provides an essential bridge between the two structures, but circuit-level organization and function of this intermediary system remain poorly understood. Here we use intersectional virus tracing and genetic strategies in mice to reveal a selective synaptic connectivity matrix between brainstem substructures and functionally distinct spinal motor neurons that regulate limb movement. The brainstem nucleus medullary reticular formation ventral part (MdV) stands out as specifically targeting subpopulations of forelimb-innervating motor neurons. Its glutamatergic premotor neurons receive synaptic input from key upper motor centres and are recruited during motor tasks. Selective neuronal ablation or silencing experiments reveal that MdV is critically important specifically for skilled motor behaviour, including accelerating rotarod and single-food-pellet reaching tasks. Our results indicate that distinct premotor brainstem nuclei access spinal subcircuits to mediate task-specific aspects of motor programs.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

Nature

Nature Magazine

0 Following 27 Fans 0 Projects 626 Articles

SIMILAR ARTICLES

Meristems encompass stem/progenitor cells that sustain postembryonic growth of all plant organs. How meristems are activated and sustained by nutrient

Read More

Transcription of ribosomal RNA by RNA polymerase (Pol) I initiates ribosome biogenesis and regulates eukaryotic cell growth. The crystal structure of P

Read More

Abstract The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainti

Read More

Abstract Ecological and societal disruptions by modern climate change are critically determined by the time frame over which climates shift beyond his

Read More

Abstract Evidence from Greenland ice cores shows that year-to-year temperature variability was probably higher in some past cold periods, but there is

Read More

Abstract The land and ocean act as a sink for fossil-fuel emissions, thereby slowing the rise of atmospheric carbon dioxide concentrations1. Although t

Read More

论文摘要 人们已经非常清楚生物多样性对初级生产力等生态系统功能有一个积极影响,但它对植物凋落物的多样性和分解植物凋落物的生物的多样性的影响却不是很清楚。Stephan H?ttenschwiler及同事对从亚北极到热带、包括水生生态系统和陆地生态系统在内的五个地点所进行的并行操纵实验中的凋落物多样性进

Read More

论文摘要 FANTOM5 (即“哺乳动物基因组-5的功能注解”) 是一个大型国际合作项目的第5大阶段,其目标是分析定义每个人类细胞类型的转录调控网络。本期Nature上的两篇Articles论文发表了该项目的一些最新结果。第一篇论文利用FANTOM5项目组的组织和原代细胞样本来定义整个人体中活性的、在

Read More

论文摘要 有证据表明,血管 (尤其是它们的内皮细胞) 控制器官的生长、平衡和再生。在本期Nature上发表的两篇论文中,Ralf Adams及同事证明,骨头血管含有专门支持骨成熟和再生的内皮细胞。Anjali Kusumbe等人在小鼠骨骼系统内识别出一个在介导骨生长中起关键作用的毛细血管亚型。这些血管

Read More

论文摘要 CD4 T细胞(携带能够识别被病毒感染的细胞表面上的CD4抗原的受体的辅助T细胞)的丧失是艾滋病发病的根源。在这项研究中,Warner Greene等人识别出静止的淋巴CD4 T细胞在HIV感染过程中被耗尽的机制。利用保持了天然淋巴环境的人淋巴组织的体外培养,本文作者发现,失败的病毒复制触发

Read More