Bączyk Marcin, Manuel Marin, Roselli Francesco, Zytnicki Daniel
Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland.
SPPIN - Saints-Pères Paris Institute for the Neurosciences, CNRS, Université de Paris, Paris, France.
Adv Neurobiol. 2022;28:131-150. doi: 10.1007/978-3-031-07167-6_6.
Although they share the common function of controlling muscle fiber contraction, spinal motoneurons display a remarkable diversity. Alpha-motoneurons are the "final common pathway", which relay all the information from spinal and supraspinal centers and allow the organism to interact with the outside world by controlling the contraction of muscle fibers in the muscles. On the other hand, gamma-motoneurons are specialized motoneurons that do not generate force and instead specifically innervate muscle fibers inside muscle spindles, which are proprioceptive organs embedded in the muscles. Beta-motoneurons are hybrid motoneurons that innervate both extrafusal and intrafusal muscle fibers. Even among alpha-motoneurons, there exists an exquisite diversity in terms of motoneuron electrical and molecular properties, physiological and structural properties of their neuromuscular junctions, and molecular and contractile properties of the innervated muscle fibers. This diversity, across species, across muscles, and across muscle fibers in a given muscle, underlie the vast repertoire of movements that one individual can perform.
尽管脊髓运动神经元都具有控制肌纤维收缩的共同功能，但它们表现出显著的多样性。α运动神经元是“最后公路”，它传递来自脊髓和脊髓上中枢的所有信息，并通过控制肌肉中的肌纤维收缩使机体与外界相互作用。另一方面，γ运动神经元是特殊的运动神经元，它们不产生力量，而是专门支配肌梭内的肌纤维，肌梭是嵌入肌肉中的本体感受器官。β运动神经元是混合运动神经元，它支配梭外和梭内肌纤维。即使在α运动神经元之间，在运动神经元的电和分子特性、其神经肌肉接头的生理和结构特性以及所支配肌纤维的分子和收缩特性方面也存在着细微的差异。这种跨物种、跨肌肉以及给定肌肉内跨肌纤维的多样性，构成了个体能够执行的大量运动技能的基础。
