抄録
On the ground, an otolith organ behaves as a detector of both gravity and linear acceleration, and plays an important role in controlling posture and eye movement for tilting of the head or translational motion. Alternatively, gravitational acceleration applied to an otolith organ disappears in a microgravity environment. However, linear acceleration can be received by an otolith organ and produce a sensation that is different from that on Earth. In this study, we examined functions of the otolith organ in goldfish revealed from the analysis of eye movement induced by linear acceleration in different body positions. We analyzed torsional eye movements from video images frame by frame. For acceleration stimulation, torsional eye movements induced during a head-down body position were larger those that induced during a head-up body position. These results suggest that the amplitude of torsional eye movements induced by linear acceleration depend on the gravity applied on the otolith organ and that the response properties may be different in microgravity.
