Where and when do we look as we approach and step over an obstacle in the travel path?
Where and when do we look as we approach and step over an obstacle in the travel path?
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DOI：
10.1097/00001756-199712010-00002
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发表时间：
1997-12-01
期刊：
影响因子：
1.7
通讯作者：
Vickers, JN
中科院分区：
文献类型：
--
作者：
Patla, AE;Vickers, JN
当佩戴移动的眼动仪的正常参与者接近并跨过旅行路径中不同高度的障碍物时，我们分析了时空凝视行为模式。旅行注视（TravFix）（当凝视稳定并以全身速度旅行时）和4-6 m区域内的注视（Fix 4 -6）。在接近障碍物的过程中，参与者在大约20%的旅行时间内专注于障碍物。只有Fix 4 -6的持续时间被调制为障碍物高度的函数，通过调节频率，并反映了增加的时间所需的检测的小的低对比度障碍物在行驶路径中ObsFix的频率增加显着的障碍物高度的函数，并反映视觉运动转换所需的肢体高度控制。参与者在跨过障碍物时并没有专注于障碍物，而是在之前的步骤中进行了规划。TravFix持续时间和频率是恒定的，而Fix 4 -6持续时间在障碍物前一步和障碍物上一步更高，反映了在避障后对引导肢体的着陆区域的视觉搜索。这些结果清楚地表明，视觉提供的障碍物信息用于前馈而不是在线控制模式来调节运动。在TravFix期间从光流中获取的关于自运动的信息可以用于控制运动的速度。
SPATIO-TEMPORAL gaze behaviour patterns were analysed as normal participants wearing a mobile eye tracker approached and stepped over obstacles of varying height in the travel path. We examined the frequency and duration of three types of gaze fixation with respect to the participants' stepping patterns: obstacle fixation (ObsFix); travel fixation (TravFix) (when the gaze is stable and travelling at the speed of whole body) and fixation in the 4-6 m region (Fix4-6). During the approach phase to the obstacle, participants fixated on the obstacle for similar to 20% of the travel time. Only Fix4-6 duration was modulated as a function of obstacle height by regulating the frequency and reflected the increased time needed for detection of the small low contrast obstacle in the travel path. Frequency of ObsFix increased significantly as a function of obstacle height and reflected visuo-motor transformation needed for limb elevation control. Participants did not fixate on the obstacle as they were stepping over, but did the planning in the steps before. TravFix duration and frequency was constant while Fix4-6 duration was higher in the step before and step over the obstacle reflecting visual search of the landing area for the lead limb following obstacle avoidance. These results clearly show that obstacle information provided by vision is used in a feed-forward rather than on-line control mode to regulate locomotion. Information about self-motion acquired from optic flow during TravFix can be used to control velocity of locomotion.