Development of Methods for Evaluating Function and Pathophysiology of Visual System (optic nerve to visual cortex).

我们应用新发展的方法来评估视觉和眼动功能，并能够获得正常人和神经眼科疾病患者的数据。1）使用宽三维视觉刺激器和眼动记录系统，我们发现视差目标后面的背景对会聚幅度有很大的影响，周边视差目标对会聚反应的初始开环部分有较强的影响，扫视型聚散运动的潜伏期大于追踪型聚散运动。从这些事实出发，我们讨论了三维视觉分析的神经机制。2）利用弥散加权磁共振成像（diffusion-weighted magnetic resonance imaging，MRI）检测表观水扩散，我们评估了视神经轴突扩散率。在急性视神经炎患者中，视神经测量的视神经管部分的弥散较小，而在慢性视神经萎缩患者中，弥散较大。这些结果对视神经疾病的鉴别诊断有很大的帮助，对视路的其他部分，如视交叉和视束的实验正在进行中。3）功能磁共振成像（Functional MRI）采用BOLD方法检测脑内局部血流量的增加，发现小脑蚓部第VII小叶与扫视和追踪眼球运动有关。结合文献，有人认为这一部分也与聚散度眼动控制有关，最近发现了同时编码旋转和聚散度眼动的神经元。我们从理论上讨论了曾经被认为是独立子系统的三维视觉信息和聚散度眼运动是如何在中枢神经系统中受到控制的，我们相信这些数据可以直接为神经眼科临床做出贡献。

We applied newly developed methods to evaluate visual and eye movement functions and was able to acquire data from normal subjects and patients with neuro-ophthalmological disease.1)Using wide three-dimensional visual stimulator and eye movement recording systems, we revealed that the background behind the disparity target had strong effect on convergence amplitude, that peripheral disparity target had strong effect on the initial open-loop part of the convergence response, and that the latency of saccade-type vergence movement was greater than that of pursuit-type vergence movement. From these facts, we discussed neuronal mechanism of three-dimensional visual analysis.2)Using diffusion-weighted magnetic resonance imaging(MRI) which detect apparent water diffusion, we evaluated axonal diffusivity of the optic nerve. In patients with acute optic neuritis, diffusion in the optic nerve measured optic canal portion was smaller, while in those with chronic optic atrophy it was greater. These results seem to be very useful for differential diagnosis of optic nerve diseases.Experiment for other parts of visual pathway, such as optic chiasm and optic tract, is now on going.3)Functional MRI using BOLD method to detect regional blood flow increase in the brain, it was revealed that lobuli VII of the cerebellar vermis is related to both saccadic and pursuit eye movements. Considered with literatures, it was suggested that this part is also related to vergence eye movement control.Recently, neuron which code both version and vergence eye movements has been discovered. We disc ussed theoretically how three dimensional visual information and vergence eye movement, which have once been considered to be independent subsystem, are controlled in the central nervous system.These data, we believe, could contribute to neuro-ophthalmology clinic directly.