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首页> 外文期刊>Journal of Neurophysiology >Dissociated hysteresis of static ocular counterroll in humans.
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Dissociated hysteresis of static ocular counterroll in humans.

机译：人体静态眼部反作用力的解离迟滞。

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In stationary head roll positions, the eyes are cyclodivergent. We asked whether this phenomenon can be explained by a static hysteresis that differs between the eyes contra- (CE) and ipsilateral (IE) to head roll. Using a motorized turntable, healthy human subjects (n = 8) were continuously rotated about the earth-horizontal naso-occipital axis. Starting from the upright position, a total of three full rotations at a constant velocity (2 degrees/s) were completed (acceleration = 0.05 degrees/s2, velocity plateau reached after 40 s). Subjects directed their gaze on a flashing laser dot straight ahead (switched on 20 ms every 2 s). Binocular three-dimensional eye movements were recorded with dual search coils that were modified (wires exiting inferiorly) to minimize torsional artifacts by the eyelids. A sinusoidal function with a first and second harmonic was fitted to torsional eye position as a function of torsional whole body position at constant turntable velocity. The amplitude and phase of the first harmonic differed significantly between the two eyes (paired t-test: P < 0.05): on average, counterroll amplitude of IE was larger [CE: 6.6 +/- 1.6 degrees (SD); IE: 8.1 +/- 1.7 degrees), whereas CE showed more position lag relative to the turntable (CE: 12.5 +/- 10.7 degrees; IE: 5.1 +/- 8.7 degrees). We conclude that cyclodivergence observed during static ocular counterroll is mainly a result of hysteresis that depends on whether eyes are contra- or ipsilateral to head roll. Static hysteresis also explains the phenomenon of residual torsion, i.e., an incomplete torsional return of the eyes when the first 360 degrees whole body rotation was completed and subjects were back in upright position (extorsion of CE: 2.0 +/- 0.10 degrees; intorsion of IE: 1.4 +/- 0.10 degrees). A computer model that includes asymmetric backlash for each eye can explain dissociated torsional hysteresis during quasi-static binocular counterroll. We hypothesize that ocular torsional hysteresis is introduced at the level of the otolith pathways because the direction-dependent torsional position lag of the eyes is related to the head roll position and not the eye position.
机译：在固定的头枕位置，眼睛是发散的。我们问这种现象是否可以用静态滞后现象来解释，该滞后现象在眼睛对侧（CE）和同侧（IE）相对于头部侧倾之间是不同的。使用电动转盘，使健康的人类受试者（n = 8）绕着地球水平的鼻枕轴线连续旋转。从直立位置开始，以恒定速度（2度/秒）完成了总共三个完整旋转（加速度= 0.05度/秒，在40 s后达到了速度平稳）。受试者将视线对准前方一个闪烁的激光点（每2秒钟打开20毫秒）。用经过修改的双搜索线圈（金属丝从下方伸出）记录双眼的三维眼动，以最大程度地减少眼睑的扭曲伪影。在恒定转盘速度下，将具有一次谐波和二次谐波的正弦函数拟合到扭转眼位置，作为扭转全身位置的函数。两只眼睛之间的一次谐波的幅度和相位存在显着差异（配对t检验：P <0.05）：平均而言，IE的反向滚动幅度更大[CE：6.6 +/- 1.6度（SD）; IE：8.1 +/- 1.7度），而CE相对于转盘显示出更大的位置滞后（CE：12.5 +/- 10.7度; IE：5.1 +/- 8.7度）。我们得出的结论是，在静态眼球反向滚动过程中观察到的环发散主要是磁滞现象的结果，磁滞现象取决于眼睛是与头侧滚动相对还是同侧。静态滞后现象还解释了残余扭转现象，即，在第一个360度全身旋转完成并且受试者回到直立位置时，眼睛的扭转不完全（CE伸展：2.0 +/- 0.10度; IE：1.4 +/- 0.10度）。包含每只眼睛不对称反冲的计算机模型可以解释准静态双眼反压期间解离的扭转滞后现象。我们假设在耳石路径的水平引入了眼部扭转迟滞，因为眼睛的方向相关的扭转位置滞后与头侧倾位置有关，而与眼睛的位置无关。

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