Differences in preferred reference frames for postural orientation shown by after-effects of stance on an inclined surface
Differences in preferred reference frames for postural orientation shown by after-effects of stance on an inclined surface
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DOI：
10.1007/s00221-004-2124-6
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发表时间：
2005-05-01
影响因子：
2
通讯作者：
Peterka, RJ
中科院分区：
文献类型：
--
作者：
Kluzik, J;Horak, FB;Peterka, RJ
这项研究报告了在闭着眼睛的倾斜表面上站立一段时间后的姿势后遗症。这种倾斜的后效维持了身体与表面的关系，就像受试者仍然站在斜坡上一样。我们调查了51名健康受试者学习后遗症的发生率和稳健性。分别于蒙眼受试者于足趾向上5度斜面站立2.5min前、中、后测量足底压力中心(COP)位置及躯干、双腿对齐情况。当表面倾斜时，所有受试者都站着，躯干和双腿接近重力垂直对齐，类似于倾斜前的对齐方式。当体表在后倾斜期恢复到水平时，受试者之间有一系列姿势对齐策略。在一个极端，受试者身体前倾，躯干平均倾斜近5度。在长达5分钟的时间里，倾斜的姿势朝着基线姿势排列呈指数式衰减。在另一个极端，受试者在后倾斜期没有倾斜，相反，相对于重力，受试者几乎保持直立。经过几天到几个月的重复测试，受试者在不同的表面倾斜方向上的倾斜后姿势行为高度一致。我们的结果表明，当视觉不可用时，个体有良好的、首选的感官策略来控制姿势定向。在后倾斜期倾斜的受试者似乎更依赖于支撑面的几何形状作为参照系，更多地依赖本体感觉信息来提取运动学关系，而不倾斜的受试者似乎更依赖重力作为参照系，更多地依赖与力和负荷相关的感觉信息。
This study reports a postural after-effect of leaning that follows a period of stance on an inclined surface with eyes closed. This leaning after-effect maintained the body-to-surface relationship as if subjects still stood on the incline. We examined the incidence and robustness of the leaning after-effect in 51 healthy subjects. The location of the center of pressure (CoP) under the feet and the alignment of the trunk and legs were measured before, during and after blindfolded subjects stood on a 5 degrees toes-up inclined surface for 2.5 min. When the surface was inclined, all subjects stood with their trunk and legs aligned near to gravity-vertical, similar to the alignment adopted in the pre-incline period. When the surface returned to horizontal in the post-incline period, there was a continuum of postural alignment strategies across subjects. At one extreme, subjects leaned forward, with an average trunk lean near 5 degrees. The leaned posture decayed exponentially toward baseline postural alignment across a period of up to 5 min. At the other extreme, subjects did not lean in the post-incline period, but instead, stayed aligned near upright with respect to gravity. Subjects were highly consistent in their post-incline postural behaviors upon repeated testing over days to months and across different directions of surface inclination. Our results suggest that individuals have well-established, preferred, sensory strategies for controlling postural orientation when vision is not available. Subjects who leaned in the postincline period appear to depend more on the geometry of the support surface as a reference frame and to rely more on proprioceptive information to extract kinematic relationships, whereas subjects who did not lean appear to depend more on gravity as a reference frame and to rely more on sensory information related to forces and load.