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

三对非尖峰巨中间神经元（G1，G2，G3 ; NGIs）以去极化或超极化分级电位对视觉刺激作出反应（Okada和Yamaguchi，1989）。在本实验中，我们得到了以下结果：在黑暗中，当身体向同侧和对侧倾斜时，NGIs会产生去极化和超极化梯度电位。在同侧平衡细胞切除的动物中，所有的NGIs只对对侧向下倾斜的超极化电位作出反应，而在对侧平衡细胞切除的动物中，它们只对同侧向下倾斜的去极化电位作出反应。在双侧Statocytomized动物，没有NGIs响应身体倾斜在黑暗中，但在存在一个顶灯，他们表现出去极化和超极化电位响应身体倾斜同侧和对侧，分别。视觉反应的幅度与身体倾斜产生的趋地反应的幅度相关。另一方面，在双侧Statocytomized动物的NGIs响应与去极化和超极化梯度电位向上，并响应基板倾斜在黑暗中的身体的纵轴。对侧步行腿的电位极性与运动方向的关系与同侧步行腿正好相反。这些结果表明，NGIs整合了来自眼睛，平衡囊和腿部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方式的感觉输入之间的相互作用增强了NGIs作为代偿性眼神经系统中的前运动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.