Magnetic resonance Imaging of human extraocular muscles in convergence
Magnetic resonance Imaging of human extraocular muscles in convergence
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DOI：
10.1152/jn.00636.2002
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发表时间：
2003-04-01
影响因子：
2.5
通讯作者：
Wright, W
中科院分区：
文献类型：
--
作者：
Demer, JL;Kono, R;Wright, W
通过对8名年轻成年人的眼眶进行三平面对比度增强磁共振成像，在双眼固定800和15 cm距离处与一只眼睛对齐的目标时，对不对称会聚过程中的眼外肌（EOM）路径进行了评价。从区域质心确定了EOM的横截面和路径。在会聚中，对齐的眼睛旋转和平移可忽略不计，而其下斜肌（IO）表现出显着的收缩增厚。在会聚时，对线眼直肌或上级斜肌（SO）的横截面没有明显的收缩变化。会聚眼向鼻侧旋转22.4 °，但平移可忽略不计。会聚的眼内（MR）和外直肌（LR）的收缩横截面的变化，和IO表现出显着的收缩增厚，而垂直直肌和SO没有。三条直线眼直肌眼外肌的前方路径可以在会聚和移位中确定，这与直肌滑轮阵列的1.9 °外旋一致。腹直肌滑轮的这种外扭转重新配置将与地球仪外扭转协调地移动滑轮，并且避免将扭转作用施加到这些EOM。外扭转直肌滑轮转移收敛是不一致的重构预测解释上市的平面的时间倾斜，而不是表明，这种时间倾斜是由于斜眼外肌神经支配的变化。缺乏地球仪翻译的收敛反对整体EOM共同收缩。EOM几何结构在收敛过程中的重构对神经元控制的单单元研究具有重要意义。
Extraocular muscle (EOM) paths during asymmetrical convergence were evaluated by tri-planar, contrast-enhanced magnetic resonance imaging of the orbits of eight young adults during binocular fixation of a target aligned to one eye at 800 and 15 cm distance. Cross sections and paths of EOMs were determined from area centroids. In convergence, the aligned eye rotated and translated negligibly, while its inferior oblique (IO) muscle exhibited significant contractile thickening. There were no significant contractile changes in the cross sections of aligned eye rectus or superior oblique (SO) muscles in convergence. The converging eye rotated nasally 22.4degrees but translated negligibly. The converging eye medial (MR) and lateral rectus (LR) muscles exhibited large contractile cross-section changes, and the IO showed significant contractile thickening, while the vertical rectus muscles and the SO did not. Anterior paths of three aligned eye rectus EOMs could be determined in convergence and shifted consistent with a 1.9degrees extorsion of the rectus pulley array. Such extorsional reconfiguration of the rectus pulleys would move the pulleys in coordination with globe extorsion and avoid imparting torsional action to these EOMs. Extorsional rectus pulley shift in convergence is inconsistent with the reconfiguration predicted to explain the temporal tilting of Listing's planes, instead suggesting that this temporal tilting is due to variations in oblique EOM innervation. Absence of globe translation in convergence argues against overall EOM co-contraction. The reconfiguration of EOM geometry in convergence has important implications for single-unit studies of neural control.