Brain Stem Neural Circuits of Horizontal and Vertical Saccade Systems and their Frame of Reference
Brain Stem Neural Circuits of Horizontal and Vertical Saccade Systems and their Frame of Reference
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DOI：
10.1016/j.neuroscience.2018.08.027
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发表时间：
2018-11
期刊：
影响因子：
3.3
通讯作者：
M. Takahashi;Y. Shinoda
中科院分区：
文献类型：
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作者：
M. Takahashi;Y. Shinoda
眼球运动（视觉和前庭）的感觉信号最初在不同的参考系中编码，但最终转化为共同的坐标，并共享相同的最终共同路径，即相同的眼外运动神经元群。根据人类的临床研究和动物的病变研究，人们普遍认为自愿眼跳运动是在水平和垂直笛卡尔坐标中组织的。然而，这个问题尚未解决，因为垂直扫视的神经回路仍未确定。我们最近结合电生理学和神经解剖学技术确定了从上丘到眼运动神经元的水平和垂直扫视的脑干神经回路。将众所周知的前庭眼通路与我们对两个上丘之间的连合兴奋和抑制的发现进行比较，我们提出眼跳系统使用与前庭眼系统相同的参考系，即共同半规管坐标。该提议主要基于以下显着相似性：（1）从一个上丘到眼外运动神经元的输出神经回路和从各自的神经管到其支配的眼外运动神经元的输出神经回路之间的显着相似性，（2）一侧向上扫视系统和另一侧向下系统之间，以及一侧前管系统和另一侧后管系统之间的连合相互抑制模式，以及（3）扫视和快速阶段的神经回路之间的显着相似性。前庭眼球震颤共享脑干爆发神经元。为了支持该提议，尽管使用半规管坐标，但上丘的连合激励可能有助于维持眼跳中的 Listing 定律。
Sensory signals for eye movements (visual and vestibular) are initially coded in different frames of reference but finally translated into common coordinates, and share the same final common pathway, namely the same population of extraocular motoneurons. From clinical studies in humans and lesion studies in animals, it is generally accepted that voluntary saccadic eye movements are organized in horizontal and vertical Cartesian coordinates. However, this issue is not settled yet, because neural circuits for vertical saccades remain unidentified. We recently determined brainstem neural circuits from the superior colliculus to ocular motoneurons for horizontal and vertical saccades with combined electrophysiological and neuroanatomical techniques. Comparing well-known vestibuloocular pathways with our findings of commissural excitation and inhibition between both superior colliculi, we proposed that the saccade system uses the same frame of reference as the vestibuloocular system, common semicircular canal coordinate. This proposal is mainly based on marked similarities (1) between output neural circuitry from one superior colliculus to extraocular motoneurons and that from a respective canal to its innervating extraocular motoneurons, (2) of patterns of commissural reciprocal inhibitions between upward saccade system on one side and downward system on the other, and between anterior canal system on one side and posterior canal system on the other, and (3) between the neural circuits of saccade and quick phase of vestibular nystagmus sharing brainstem burst neurons. In support of the proposal, commissural excitation of the superior colliculi may help to maintain Listing’s law in saccades in spite of using semicircular canal coordinate.