Multisensory integration in the nonspiking giant interneurons, with special reference to the compensatory oculomotor response

三对非尖峰巨型中间神经元（G1、G2、G3; NGIs）对视觉刺激产生去极化或超极化梯度电位反应（Okada和Yamaguchi， 1989）。在目前的实验中，我们得到了以下结果。在黑暗中，NGIs以去极化和超极化梯度电位响应身体向单侧和对侧倾斜。在同侧静囊切除动物中，所有NGIs仅对对侧侧下倾斜有超极化电位反应，而在对侧静囊切除动物中，它们仅对同侧侧下倾斜有去极化电位反应。在双侧静囊切除的动物中，NGIs在黑暗中对身体倾斜没有反应，但在头顶有光的情况下，它们分别表现出对身体向单侧和对侧倾斜的去极化和超极化电位。视觉反应的振幅随身体倾斜产生的地理策略反应的振幅而变化。另一方面，在双侧静囊切除的动物中，NGIs在黑暗中以去极化和超极化梯度电位向上响应，并响应基底在身体纵轴上的倾斜。对侧行走腿电位极性与运动方向的关系与同侧行走腿电位极性与运动方向的关系正好相反。在完整的动物中，NGIs对黑暗中的腿部运动几乎没有反应。这些结果表明，NGIs整合了来自眼睛、静止囊和腿本体感受器的感觉输入，并且来自左右感觉器官的相同或不同模态的感觉输入之间的相互作用增强了NGIs作为代偿性动眼肌系统中运动前神经元的方向敏感性。

Three pairs of nonspiking giant interneurons (G1, G2, G3 ; NGIs) respond with depolarizing or hyperpolarizing graded potentials to visual stimuli (Okada and Yamaguchi, 1989). In the present experiments, we obtained the following results.The NGIs respond with depolarizing and hyperpolarizing graded potentials to body tilt in roll to the ipsi- and contralateral sides in the dark. In ipsilaterally statocystectomized animals, all the NGIs respond with hyperpolarizing potentials only to the contralateral side-down tilt, whereas in contralaterally statocystectomized animals, they respond with depolarizing potentials only to the ipsilateral side-down tilt. In bilaterally statocystectomized animals, none of the NGIs respond to body tilt in the dark, but in the presence of a overhead light, they exhibit depolarizing and hyperpolarizing potentials in response to body tilt to the ipsi- and contralateral sides, respectively. The amplitude of visual responses varies in association with the amplitude of the geotactic response produced by body tilt. On the other hand, in bilaterally statocystectomized animals the NGIs respond with depolarizing and hyperpolarizing graded potentials to upward and respond to substrate tilt about the longitudinal axis of the body in the dark. Relationships between the polarity of potential and the direction of movement in the contralateral walking legs were just opposite to those in the ipsilateral walking legs. In intact animals the NGIs hardly respond to leg movements in the dark.These results indicate that the NGIs integrate the sensory inputs from eyes, statocysts, and leg proprioceptors and that the interaction between sensory inputs from the left and right sensory organs with either the same modality or with different modalities enhance the directional sensitivity of NGIs as premotoneurons in the compensatory oculomotor system.