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

在抛物线飞行低重力状态下，观察鲤鱼背侧光倾斜反应(DLTR)和小脑电活动的变化。这个项目属于我们为日本航天飞机任务(Spacelab-J)提出的“空间运动病”研究的一系列初步实验，该任务原定于1988年进行，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)的能力评估也参与了这项研究。得到的结论和结果如下：1.每一次抛物线飞行可获得约20秒的微重力持续时间，微重力低于0.05 Gz。持续时间和重力水平可能会令人满意地长得足够低，足以推进某些类型的太空科学研究的初步研究。完全依赖光的反应和相当高的倾斜速度(DLTR)是完整鲤鱼暴露在抛物线飞行低重力下的特征。这表明由于前庭输入的丢失，视觉-前庭相互作用对于姿势控制来说是不平衡的。在太空长时间失重期间，将检查DLTR模式的可能修改。微重力下小脑活动的功率谱分析表明，在8赫兹以下和12-25赫兹之间的频率范围内，小脑活动的功率增强。活动可能恢复的情况将在空间飞行任务中跟进。

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.