Analysis of dorsal light tilt reaction and cerebellar activities in carp during aircraft parabolic-flight weightlessness

研究了低重力抛物线飞行条件下鲤鱼背光倾斜反应（DLTR）和小脑电活动的变化。本项目属于我们为日本航天飞机任务（Spacelab-J）提出的“空间晕动病”研究的一系列初步实验，该计划原定于1988年，但在挑战者号事故后改为1991年。由于在本项目实现之前，日本从未将这种抛物线飞行应用于科学研究，因此对所选飞机（三菱MU-300）的能力进行评估也参与了这项研究。所得结论和结果如下：1。在微重力低于0.05 Gz的情况下，每次抛物线飞行的持续时间约为20秒。持续时间和重力水平可能长得令人满意，低得足以进行一些太空科学研究的初步研究。在低重力抛物线飞行条件下，完整的鲤鱼具有完全依赖于光的高倾斜速度（DLTR）。这表明由于前庭输入的丧失，姿势控制的视觉-前庭交互作用不平衡。在长时间的太空失重状态下，将研究DLTR模式的可能修改。对微重力下小脑活动的功率谱分析显示，在8赫兹以下和12-25赫兹之间的频率范围内，功率增强。在活动中可能的恢复将在太空任务中进行。

The dorsal light tilt reaction (DLTR) of carp and electrical activity of the cerebellum were examined under parabolic-flight low gravity. This project belongs to a series of preliminary experiments for our proposal of "space motion sickness" research for the Space Shuttle mission of Japan (Spacelab-J) which was originally scheduled in 1988 but changed later to 1991 after the accident of Challenger. Since such parabolic-flight application to scientific research had never been performed in Japan until the present project was realized, an evaluation of capability for the aircraft chosen (Mitsubishi MU-300) also involved in this research. The conclusion and results obtained are as follows:1. About 20 seconds of duration with a microgravity below 0.05 Gz could be attained for each parabolic flight. The duration and gravity level may be satisfactorily long and low enough to advance some kinds of preliminary studies for scientific research in space.2. A completely light-dependent reaction with a rather high speed of the tilting (DLTR) was a characteristic feature of the intact carp exposed to the parabolic-flight low gravity. It indicates unbalanced visual-vestibular interaction for the posture control due to loss of the vestibular input. Possible modification of DLTR pattern will be examined during the prolonged weightlessness in space.3. A power spectral analysis of the cerebellar activity under microgravity showed enhancement of the power at the frequency ranges below 8 Hz and between 12-25 Hz. Possible recovery in the activity will be followed in the space mission.