The vestibuloocular reflex of the adult flatfish. I. Oculomotor organization.
The vestibuloocular reflex of the adult flatfish. I. Oculomotor organization.
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成年比目鱼的前庭眼反射。
DOI：
10.1152/jn.1985.54.4.887
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发表时间：
1985
影响因子：
2.5
通讯作者：
Baker,R
中科院分区：
文献类型：
--
作者：
Graf,W;Baker,R
比目鱼物种构成了研究脊椎动物中枢神经系统适应性变化的自然范例。在变态过程中，所有种类的比目鱼都经历了前庭和眼外坐标轴之间的90度方向变化。因此，双眼的光轴保持其相对于地球水平的方向，但水平半规管变得垂直定向。由于比目鱼以与正常鱼相同的游泳运动推进其身体，因此水平运河暴露于相同的加速度，但在比目鱼中，这些加速度发生在垂直平面内。适当的补偿性眼球运动是双眼同时向前或向后旋转（即，平行），与直立鱼的对称眼睛运动（即，一只眼睛向前移动，另一只眼睛向后移动）。因此，需要改变眼外肌排列和/或神经元连接。本研究描述了美洲拟鲽（Pseudopleuronectes americanus）成鱼的外周和中央眼丘组织。在水平的周边眼外器，水平眼外肌（外直肌和内直肌）的大小是相当小的垂直眼肌，量化的纤维计数和面积测量的横截面的个别肌肉。然而，所有六个眼外肌的空间取向和运动学特征与可比较的侧眼动物中描述的那些没有不同。左眼和右眼之间没有可检测到的不对称。通过向个体眼肌中注射细胞外辣根过氧化物酶来研究中央眼组织。眼外肌运动神经元在眼神经核、转臂神经核和外展神经核中的分布较为常见，这些运动神经元包括两个对侧（上级直肌和上级斜肌）和四个同侧（下斜肌、下直肌、内直肌和外直肌）。标记的细胞形成不同的运动神经元群，重叠很少。正如预期的那样，标记的运动神经元的数量不同的水平和垂直眼运动。在比较展神经核与垂直直肌分支时，数值差异尤其显著。然而，投射到左右眼的运动神经元之间存在双侧对称性。（400字处截断摘要）
The flatfish species constitute a natural paradigm for investigating adaptive changes in the vertebrate central nervous system. During metamorphosis all species of flatfish experience a 90 degree change in orientation between their vestibular and extraocular coordinate axes. As a result, the optic axes of both eyes maintain their orientation with respect to earth horizontal, but the horizontal semicircular canals become oriented vertically. Since the flatfish propels its body with the same swimming movements when referenced to the body as a normal fish, the horizontal canals are exposed to identical accelerations, but in the flatfish these accelerations occur in a vertical plane. The appropriate compensatory eye movements are simultaneous rotations of both eyes forward or backward (i.e., parallel), in contrast to the symmetric eye movements in upright fish (i.e., one eye moves forward, the other backward). Therefore, changes in the extraocular muscle arrangement and/or the neuronal connectivity are required. This study describes the peripheral and central oculomotor organization in the adult winter flounder, Pseudopleuronectes americanus. At the level of the peripheral oculomotor apparatus, the sizes of the horizontal extraocular muscles (lateral and medial rectus) were considerably smaller than those of the vertical eye muscles, as quantified by fiber counts and area measurements of cross sections of individual muscles. However, the spatial orientations and the kinematic characteristics of all six extraocular muscles were not different from those described in comparable lateral-eyed animals. There were no detectable asymmetries between the left and the right eye. Central oculomotor organization was investigated by extracellular horseradish peroxidase injections into individual eye muscles. Commonly described distributions of extraocular motor neurons in the oculomotor, trochlear, and abducens nuclei were found. These motor neuron pools consisted of two contralateral (superior rectus and superior oblique) and four ipsilateral populations (inferior oblique, inferior rectus, medial rectus, and lateral rectus). The labeled cells formed distinct motor neuron populations, which overlapped little. As expected, the numbers of labeled motoneurons differed in horizontal and vertical eye movers. The numerical difference was especially prominent in comparing the abducens nucleus with one of the vertical recti subdivisions. Nevertheless, there was bilateral symmetry between the motoneurons projecting to the left and right eyes.(ABSTRACT TRUNCATED AT 400 WORDS)