RF SSC, Institute for Biomedical Problems, Moscow, Russia.
J Vestib Res. 2013;23(1):3-12. doi: 10.3233/VES-130470.
The aim of the study was to examine effects of long-duration exposure to weightlessness on characteristics of the vertical gaze fixation reaction (GFR). The subjects were to perform the target acquisition task on visual stimuli that appeared at a distance of 16 deg. up- and down from the primary position in a random order. Experiments were performed before launch, during flight and after landing. Before flight time of gaze fixation reaction did not exceed 650 ms. During space flight (SF) it extended up to 900-1000 ms and more. The velocities of head movement in space decreased, but the velocities of eye counterrotation decreased to a lesser degree. This difference resulted in sharp increase of vertical vestibular ocular reflex (VOR) gain (up to 4.3 values in one of the cosmonauts) during the 1st month of flight; further it decreased reaching the values of 0.5-0.7 on the 5th month of SF. After landing vertical VOR gain increased greatly again. These results in the vertical axis are in agreement with the data of Kozlovskaya et al., which showed in experiments with monkeys that horizontal VOR gain increased together with redundant inadequate responses of vestibular nucleus on vestibular stimulation and that in the course of adaptation to these conditions central nervous system inhibited vestibular input from the motor control system.
本研究旨在探讨长期失重对垂直凝视固视反应（GFR）特征的影响。受试者将在距主位 16 度的距离上以随机顺序执行目标获取任务，视觉刺激向上和向下出现。实验在发射前、飞行中和着陆后进行。飞行前的凝视固视反应时间不超过 650 毫秒。在太空飞行（SF）期间，它延长到 900-1000 毫秒甚至更长。头部在太空中的运动速度降低，但眼睛反向旋转的速度降低幅度较小。这种差异导致在飞行的第一个月，垂直前庭眼反射（VOR）增益急剧增加（在一名宇航员中高达 4.3 倍）；进一步降低，在 SF 的第 5 个月达到 0.5-0.7 的数值。着陆后，垂直 VOR 增益再次大幅增加。这些在垂直轴上的结果与 Kozlovskaya 等人的实验数据一致，该实验表明，在猴子实验中，水平 VOR 增益随着前庭刺激时前庭核的冗余不足反应而增加，并且在适应这些条件的过程中，中枢神经系统抑制了前庭输入从运动控制系统。
