SPATIAL ORIENTATION OF THE VESTIBULAR SYSTEM - DEPENDENCE OF OPTOKINETIC AFTER-NYSTAGMUS ON GRAVITY
SPATIAL ORIENTATION OF THE VESTIBULAR SYSTEM - DEPENDENCE OF OPTOKINETIC AFTER-NYSTAGMUS ON GRAVITY
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DOI：
10.1152/jn.1991.66.4.1422
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发表时间：
1991-10-01
影响因子：
2.5
通讯作者：
COHEN, B
中科院分区：
文献类型：
--
作者：
DAI, MJ;RAPHAN, T;COHEN, B
1.猴子以60度/秒的速度接受关于他们的偏航（动物垂直）和俯仰（动物水平）轴以及冠状面中其他以头部为中心的轴的视动刺激。动物直立或相对于重力以右侧向下的姿势倾斜。刺激诱发水平、垂直和斜向视动性眼球震颤（OKN）。OKN后出现视动性后眼球震颤（OKAN），在黑暗中记录.当猴子倾斜，刺激，产生水平或偏航轴眼速度在OKN诱导的垂直或俯仰分量的慢相速度在OKAN。这被称为OKAN的“交叉耦合”。与系统生成OKAN相关的特征值和特征向量被发现作为倾斜的函数。它们是通过使用Levenberg-Marquardt算法来确定的，以最小化OKAN模型的输出与数据之间的均方误差。与偏航OKAN（偏航轴特征向量）相关联的特征向量保持接近于空间垂直，而不管倾斜角度如何。与音高相关的特征向量OKAN（音高轴特征向量）总是与体轴对齐。数据表明，速度存储可以用分段线性系统来建模，其结构依赖于重力和偏航轴特征向量，倾向于与重力对齐.偏航轴特征向量也确定了视动刺激的冠状面与动物在各种角度的倾斜头为中心的轴。开发了一种使用残差谱分析的技术来估计偏航和俯仰OKAN慢相速度是否以相同的相对速率和在相同的时间过程中同时衰减。该方法确定的特征向量与分析偏航OKN引起的OKAN得到的特征向量一致。在偏航OKN与动物在倾斜的位置，随后的眼震的平均向量更接近身体轴比空间垂直。这表明在OKN期间存在对交叉耦合音高分量的抑制。刺激的方向可以用于抑制与刺激运动的方向不一致的速度存储的分量。猴子的特征向量和人类感知的空间垂直之间有相似之处，向上和向下的眼速度的特征向量的平均值覆盖人类1-g感知数据。OKAN的动力学可以提供一个模型，可以用来研究在重力环境中响应重力以及运动的神经基础。
1. Monkeys received optokinetic stimulation at 60-degrees/s about their yaw (animal vertical) and pitch (animal horizontal) axes, as well as about other head-centered axes in the coronal plane. The animals were upright or tilted in right-side-down positions with regard to gravity. The stimuli induced horizontal, vertical, and oblique optokinetic nystagmus (OKN). OKN was followed by optokinetic after-nystagmus (OKAN), which was recorded in darkness.2. When monkeys were tilted, stimulation that generated horizontal or yaw axis eye velocity during OKN induced a vertical or pitch component of slow phase velocity during OKAN. This has been designated as "cross-coupling" of OKAN. Eigenvalues and eigenvectors associated with the system generating OKAN were found as a function of tilt. They were determined by use of the Levenberg-Marquardt algorithm to minimize the mean square error between the output of a model of OKAN and the data.3. The eigenvector associated with yaw OKAN (yaw axis eigenvector) was maintained close to the spatial vertical regardless of the angle of tilt. The eigenvector associated with pitch OKAN (pitch axis eigenvector) was always aligned with the body axis. The data indicate that velocity storage can be modeled by a piecewise linear system, the structure of which is dependent on gravity and the yaw axis eigenvector, which tends to align with gravity.4. Yaw axis eigenvectors were also determined by giving optokinetic stimulation about head-centered axes in the coronal plane with the animal in various angles of tilt. A technique using a spectral analysis of residuals was developed to estimate whether yaw and pitch OKAN slow phase velocities decayed concurrently at the same relative rate and over the same time course. The eigenvectors determined by this method were in agreement with those obtained by analyzing OKAN elicited by yaw OKN.5. During yaw OKN with the animal in tilted positions, the mean vector of the ensuing nystagmus was closer to the body axis than to the spatial vertical. This suggests that there is suppression of the cross-coupled pitch component during OKN. The direction of the stimulus may be utilized to suppress components of velocity storage not coincident with the direction of stimulus motion.6. There were similarities between the monkey eigenvectors and human perception of the spatial vertical, and the mean of eigenvectors for upward and downward eye velocities overlay human 1-g perceptual data. The dynamics of OKAN may provide a model that can be utilized to study the neural basis for responding to gravity as well as motion in a gravitational environment.