Influence of motion parallax in the control of spontaneous body sway
Influence of motion parallax in the control of spontaneous body sway
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DOI：
10.1007/s002219900307
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发表时间：
2000-03-01
影响因子：
2
通讯作者：
Bronstein, AM
中科院分区：
文献类型：
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作者：
Guerraz, M;Sakellari, V;Bronstein, AM
研究了正常人在安静站立时对姿势摆动的视觉控制，以了解运动视差提示是否能够改善姿势稳定性。在实验一中，六名正常受试者单独或在全房间照明的情况下注视着一个荧光前景目标。结果表明，当背景可见时，受试者会减少身体的摇摆。然而，这种效应不仅可以通过视差提示来调节，还可以通过涉及到的视野总面积的增加来调节。在实验2中，控制了图像角度大小和目标距离等其他参数。在一个黑暗的房间里，12名受试者注视着一个两个发光二极管(LED)的靶子，该靶子放置在距离他们眼睛45厘米的地方。第二个类似的双LED靶点放置在距固定靶点170 cm(最大视差)或85 cm(中等视差)处，或在固定靶点的同一平面(0 cm，无视差)。结果发现，摇摆的幅度显著降低，约为20%。当两个目标被深度呈现时(视差存在)，而不是它们在同一平面上时(没有视差)。这种影响只存在于侧向和摇摆的低频成分(高达0.5赫兹)。在实验3中，我们用与实验2相似的设计在8个受试者身上证实了运动视差对身体摇摆的影响是单目的，因为单目和双目视觉都是观察到的。基于这些结果的几何学考虑支持身体摇摆的两种视觉检测模式的存在，即传入(视网膜滑动)和传出(基于视网膜外或眼动)。
Visual control of postural sway during quiet standing was investigated in normal subjects to see if motion parallax cues were able to improve postural stability. In experiment I. six normal subjects fixated a fluorescent foreground target, either alone or in the presence of full room illumination. The results showed that subjects reduced body sway when the background was visible. This effect, however, could be mediated not only by parallax cues but also by an increase in the total area of visual field involved. In experiment 2, other parameters such as image angular size and target distance were controlled for. Twelve subjects fixated a two light-emitting diode (LED) target placed at 45 cm from their eyes in a dark room. A second similar two-LED target was placed either at 170 cm (maximum parallax) or at 85 cm (medium parallax) from the fixated target, or in the same plane of the fixated target (0 cm, no parallax). It was Found that the amplitude of sway was reduced significantly, by approximately 20%. when the two targets were presented in depth (parallax present) as compared to when they were in the same plane (no parallax). The effect was only present in the lateral direction and for low frequency components of sway (up to 0.5 Hz). We confirmed in experiment 3 on eight subjects with a design similar to that used in experiment 2 that the effect of motion parallax on body sway was of monocular origin since observed with monocular and binocular vision. Geometrical considerations based on these results support the existence of two modes of visual detection of body sway, afferent (retinal slippage) and efferent (extraretinal or eye-movement based).