垂直視差による眼球位置情報の変化が頭部方向の制御に及ぼす影響

摘要

私たちは普段，主に眼から入力される視覚情報を使って自分の周囲の空間構造を認識しながら生活している．周囲の空間構造，物体の配置を知るということには，対象の自分に対する方向を知るということが含まれる．対象の方向を知るための方法は大きく分けて2つある．1つは頭部および眼を動かす筋肉の動きから頭の位置を知る直接的な方法，もう1つは網膜に映る視覚情報のみから頭部方向を知る間接的な方法である．%Geometrically, a pattern of vertical disparity can be used as a cue to know visual direction. In our previous study, we found a tendency that unconscious head movement was induced by the change of vertical disparity. This fact indicated that that vertical disparity had an effect on the control of head direction. However, the size of head movement induced by the change of vertical disparity was very small relative to the geometrical prediction. A possible reason would be that the perception of head direction is obtained by the process to integrate information from many cues, such as, the feedback of eye muscle, vertical disparity, other visual cues, and so on and the effect of vertical disparity is quite weak when the information form the other cues are available. In this study, we examined the effect of vertical disparity on the control of head direction further, under the condition in which information from eye muscle was reduced. The results showed that vertical disparity has an effect on the control of head direction, too, although the effect is very small. This fact indicates that the role of vertical disparity in the mechanism to control head direction would be a trigger of the head movement.