Visual self-motion information is known to contribute to postural control, but it is unclear precisely which aspects of visual motion information drive changes in posture. We report here results for standing humans which suggest that there is a speed of movement threshold that must be exceeded by a visual stimulus if a posture response is to be generated. We use signal-to-noise ratio (SNR) methods to measure the strength of steady-state visually evoked posture responses (SSVEPRs) to sinusoidal modulations of visual viewpoint position in a virtual environment (VE). Using threshold estimates found from data which show how posture responses depend on visual stimulus amplitude, we show that the sensitivity of the visuo-postural response system increases with the temporal frequency at which the position of one's viewpoint is modulated. We show further that there is a speed of movement threshold, on average 1.85 cm/s, which must be exceeded by a left-right modulation of viewpoint position if a posture response is to be generated. A comparison of visual stimulus visibility to posture response thresholds suggests that one tends to not make postural responses to visual stimuli that are unseen. Finally, we found small correlations between motion sickness in these experiments and both the time spent in the VE and the frequency of viewpoint movement.

中文翻译：

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对虚拟环境中视点位置的正弦调制的姿势响应。

视觉自我运动信息有助于姿势控制，但目前尚不清楚视觉运动信息的哪些方面驱动姿势的变化。我们在这里报告站立人类的结果，这表明如果要生成姿势响应，则视觉刺激必须超过运动速度阈值。我们使用信噪比（SNR）方法来测量对虚拟环境（VE）中视点位置的正弦调制的稳态视觉诱发姿势响应（SSVEPRs）的强度。使用从数据中发现的阈值估计值，这些数据显示了姿势响应如何取决于视觉刺激幅度，我们表明，视觉姿势响应系统的灵敏度随人的视点位置被调制的时间频率而增加。我们进一步表明，存在移动速度阈值，平均为1.85 cm / s，如果要生成姿势响应，则必须由视点位置的左右调制来超过该阈值。视觉刺激可见性与姿势反应阈值的比较表明，人们往往不会对看不见的视觉刺激做出姿势反应。最后，我们在这些实验中发现晕动病与在VE中花费的时间和视点移动的频率之间存在较小的相关性。视觉刺激可见性与姿势反应阈值的比较表明，人们往往不会对看不见的视觉刺激做出姿势反应。最后，我们在这些实验中发现晕动病与在VE中花费的时间和视点移动的频率之间存在较小的相关性。视觉刺激可见性与姿势反应阈值的比较表明，人们往往不会对看不见的视觉刺激做出姿势反应。最后，我们在这些实验中发现晕动病与在VE中花费的时间和视点移动的频率之间存在较小的相关性。