Siegler M V, Phong M P, Pousman C A
Department of Biology, Emory University, Atlanta, Georgia 30322.
J Comp Neurol. 1991 Sep 15;311(3):342-55. doi: 10.1002/cne.903110305.
The motor neurons supplying the dorsoventral wing muscles in the metathorax of the grasshopper Schistocerca americana were stained by backfilling muscle-nerves with cobaltous chloride, which was then precipitated and intensified as silver sulfide. Stained motor neurons were examined in wholemounts and in sectioned ganglia. Two unifunctional muscles are innervated by a single motor neuron each, whereas four bifunctional muscles, involved in leg and wing movements, are innervated by two or three motor neurons each. Each of the motor neurons is in one of four identified anatomical groups. All members of a group have primary neurites that enter the ganglion core as part of an anatomically defined bundle and have cell bodies that lie near each other in the ganglion cortex (Siegler and Pousman, J Comp Neurol: 297:298, 1990). The morphology of the neuropilar branches of the motor neurons is correlated with the pairwise topographic arrangement of the target muscles rather than the muscles' functions. Thus, motor neurons that innervate antagonistic pairs of muscles may be more similar in morphology than motor neurons that innervate synergistic muscles. We find no evidence that particular main branches of the different motor neurons are uniquely associated with a particular motor function. Significant differences in the nature and distribution of synaptic inputs to motor neurons of different function would necessarily be expected as a basis for known differences in synaptic connectivity, but may not be apparent at the level of resolution available from light microscope examination.
通过用氯化钴对肌肉神经进行逆向填充，然后将其沉淀并强化为硫化银，对美洲沙漠蝗后胸背腹侧翅肌的运动神经元进行了染色。在整装标本和切片神经节中对染色的运动神经元进行了检查。两块单功能肌肉分别由单个运动神经元支配，而四块参与腿部和翅膀运动的双功能肌肉则分别由两个或三个运动神经元支配。每个运动神经元都属于四个已确定的解剖学组之一。一个组的所有成员都有作为解剖学定义束的一部分进入神经节核心的初级神经突，并且它们的细胞体在神经节皮质中彼此相邻（Siegler和Pousman，《比较神经学杂志》：297:298，1990）。运动神经元的神经纤维分支形态与目标肌肉的成对地形排列相关，而不是与肌肉的功能相关。因此，支配拮抗肌对的运动神经元在形态上可能比支配协同肌的运动神经元更相似。我们没有发现证据表明不同运动神经元的特定主要分支与特定运动功能有独特关联。不同功能的运动神经元突触输入的性质和分布必然存在显著差异，这是已知突触连接差异的基础，但在光学显微镜检查的分辨率水平上可能并不明显。
