ADAPTIVE CHANGES IN VESTIBULAR SYSTEM

比目鱼构成了研究适应性变化的自然范例 在中枢神经系统，因为它们的前庭和动眼神经 坐标系在以下过程中经历90度相对位移 蜕变。这种置换需要引入一种新的 前庭编码信号传输的转换系数 坐标转换成以眼肌坐标编码的运动指令。我们的 以前的研究表明，在第二级的水平上有戏剧性的重新连接 前庭神经元连接到水平管系统，表现为 垂直动眼神经元池中广泛的终末模式 到目前为止，研究的所有其他脊椎动物都没有这种联系。 实验计划给出一个完整的描述前和 比目鱼变态后前庭-眼反射(VOR)系统。 这包括，首先，细胞外和细胞间的HRP应用 双迷路前庭初级和次级传入神经的水平 包括对周围神经供应的定量分析 显示迷路对称性的前庭终末器官 连接以及两次细胞内记录以确定 已识别的次级前庭的兴奋或抑制性质 VOR系统推-拉系统内的神经元。第二， 视动刺激期间的细胞外记录将提供 关于这些动物视觉空间组织的信息。 第三，在警觉的比目鱼行为上的实验将揭示 形态描述的结构-功能关系 与鱼的实际眼球运动的联系。四、实验 在变态前期和变态的动物中，以及在被锁定的鱼类中 在某些阶段的蜕变将揭示 这些新形成的连接的出现，无论它们起源于 新生的神经元或来自已经存在的突触连接 之前。这些实验涉及创造超维度 通过环境和药物操作的幼虫，以及 放射自显影技术的使用。拟议中的实验不会 只是描述成人VOR系统的一个全面的方法 比目鱼，但也提供了关于一种 适用于大脑，特别是在适应性可塑性的背景下 实验微扰。

Flatfish constitute a natural paradigm for investigating adaptive changes in the central nervous system, because their vestibular and oculomotor coordinate systems undergo a 90 degrees relative displacement during metamorphosis. This displacement requires the introduction of a new conversion factor for the transmission of signals coded in vestibular coordinates into motor commands coded in eye muscle coordinates. Our previous studies revealed a dramatic rewiring at the level of secondary vestibular neurons connected to the horizontal canal system, exhibiting an extensive termination pattern in vertical oculomotor neuron pools via connections which are absent in all other vertebrates studied so far. Experiments are planned to give a full description of the pre- and postmetamorphic vestibulo-ocular reflex (VOR) system in the flatfish. These include, first, extracellular and intercellular HRP applications at the level of primary and secondary vestibular afferents of both labyrinths including a quantitative analysis of the peripheral nerves supplying vestibular end-organs in order to demonstrate symmetry of the labyrinthine connections as well as double intracellular recordings to ascertain the excitatory or inhibitory nature of the identified secondary vestibular neurons within the push-pull system of the VOR system. Secondly, extracellular recordings during optokinetic stimulation will provide information about the organization of the visual space of these animals. Thirdly, experiments in the alert behaving flatfish will reveal the structure-function relationship of the morphologically described connections to the actual eye movements of the fish. Fourth, experiments in premetamorphic and metamorphosing animals and in fish which are locked in certain stages of the metamorphosis will reveal the nature of the occurrance of these newly formed connections, whether they originate from newly born neurons or from synaptic connections which have been there previously. These experiments involve the creation of hyperdimensional larvae by environmental and pharmacological manipulations, as well as the usage of autoradiographic techniques. The proposed experiments would not only be a comprehensive way to describe the VOR system in the adult flatfish, but also give information about the mechanisms involved in an adpating brain, especially in the context of adaptive plasticity during experimental perturbation.