Sekine Motoki, Takahashi Masahiro, Iida Masahiro
Department of Otolaryngology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
Tokai J Exp Clin Med. 2009 Dec 20;34(4):135-41.
To detect the effect of microgravity on vestibular responses, we conducted Coriolis stimulation experiments at 1 G and μ G. Five men with vision occluded were asked to tilt their head forward while rotating at 100 degrees/sec. Postural changes were recorded by a 3D linear accelerometer, and the distance of upper body movement was derived from recordings of linear acceleration. Eye movements were recorded by a CCD camera. For a second period after commencing head tilt, the upper body moved 10 cm in the direction of inertia input at 1 G, but it moved to the opposite direction at μ G, i.e., 4 cm in the direction of inertia force. Nystagmus peak slow-phase velocity immediately after head tilt and its attenuation process did not differ between 1 G and μ G. The strength of movement sensation and the severity of motion sickness were far weaker at μ G than at 1 G. It was concluded that inertia input is valid to induce postural and sensation responses only when the external reference is given Z axis by gravity. Vestibular ocular response may be maintained at μ G because the head reference is valid even after the external reference becomes arbitrary.
为检测微重力对前庭反应的影响，我们在1G和微重力条件下进行了科里奥利刺激实验。五名视力被遮挡的男性被要求在以100度/秒的速度旋转时向前倾斜头部。姿势变化由三维线性加速度计记录，上半身移动距离由线性加速度记录得出。眼球运动由电荷耦合器件相机记录。在开始头部倾斜后的第二个时间段，上半身在1G时沿惯性输入方向移动了10厘米，但在微重力条件下则向相反方向移动，即在惯性力方向移动了4厘米。头部倾斜后立即出现的眼震慢相峰值速度及其衰减过程在1G和微重力条件下并无差异。在微重力条件下，运动感觉的强度和晕动病的严重程度远低于1G。得出的结论是，只有当重力给出外部参考Z轴时，惯性输入才有效地诱发姿势和感觉反应。即使外部参考变得任意，由于头部参考仍然有效，前庭眼反射在微重力条件下仍可能得以维持。
