Abstract

Aim of the study

In upright standing, the human foot sole is the only point of contact with the ground conveying information about the pressure distribution under the feet. We examined how the altered somatosensory input from the plantar foot receptors, when standing on a soft surface, affects the subjective estimation of the earth vertical in different sensory contexts.

Materials and methods

Twelve (12) healthy young females (mean age: 21.8 ± 2.4 years) adjusted the orientation of a visual line (35 × 1.5 cm) representing the roll orientation of a hand-held (attached on a 24.9 × 4 cm cylinder) or head-attached electromagnetic tracking sensor (Nest of Birds, Ascension Technologies Inc., VT. USA, 60 Hz) under two visual conditions (eyes open, eyes closed) while standing on a soft or firm surface. The mean absolute (accuracy) and variable (precision) error in the verticality estimate was depicted in the sensor’s roll deviation from the gravitational vertical.

Results

The accuracy and the precision of the estimate decreased in the absence of vision, while standing on the soft surface and when the estimate was provided by an active hand rather than head rotation. The surface effect was significant only in the absence of vision and when the estimate was provided by the hand.

Conclusions

The contribution of the plantar foot mechanoreceptors to gravity perception is sensory context dependent. Perception of the earth vertical is more accurate when estimated by active head rotation due to the integration of the vestibular and neck proprioceptive afferents.

中文翻译：

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足底的体感反馈是否有助于垂直度感知？

摘要

研究目的

在直立状态下，人的脚底是唯一与地面接触的点，传达有关脚下压力分布的信息。我们研究了当站在柔软的表面上时，来自足底感受器的体感输入的改变如何影响不同感官环境中对地球垂直方向的主观估计。

材料和方法

十二 (12) 名健康年轻女性（平均年龄：21.8 ± 2.4 岁）调整了视线（35 × 1.5 厘米）的方向，代表手持设备（附在 24.9 × 4 厘米圆柱上）或头部的滚动方向- 附加的电磁跟踪传感器（鸟巢，Ascension Technologies Inc.，VT. USA，60 Hz）在两种视觉条件下（睁眼，闭眼），同时站在柔软或坚固的表面上。垂直度估计中的平均绝对（准确度）和可变（精确度）误差用传感器与重力垂直的滚动偏差来描述。

结果

在没有视觉的情况下，当站立在柔软的表面上并且估计是由主动手而不是头部旋转提供时，估计的准确性和精确度会降低。只有在没有视觉和用手提供估计值时，表面效应才显着。

结论

足底机械感受器对重力感知的贡献取决于感官环境。由于前庭和颈部本体感觉传入的整合，当通过主动头部旋转估计时，对地球垂直的感知更准确。