The interaction of visual, vestibular and extra-retinal mechanisms in the control of head and gaze during head-free pursuit.
The interaction of visual, vestibular and extra-retinal mechanisms in the control of head and gaze during head-free pursuit.
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DOI：
10.1113/jphysiol.2010.199471
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发表时间：
2011-04-01
期刊：
影响因子：
--
通讯作者：
Barnes GR
中科院分区：
文献类型：
--
作者：
Ackerley R;Barnes GR
在日常生活中，我们遇到移动的物体，并遵循他们，我们已经制定了顺利的追求眼球运动。当你转动头部时，前庭眼反射被激活，这会产生补偿性的平滑眼球运动，使你的眼睛保持专注于当前感兴趣的物体。以前的研究表明，你可以克服这种反射，用眼睛和头一起跟随移动的物体，但这通常需要视觉反馈。目前的研究表明，在某些情况下，例如当你可以预测物体的运动时，你可以使用大脑中的预测机制来补充你的追踪运动，以便在物体消失时继续跟踪它。我们证明，你可以采样和存储简短的视觉运动追求一个看不见的移动对象。此外，你可以更准确地跟随它与你的眼睛和头部一起，而不是只使用你的眼睛。在跟踪移动物体时，协调眼睛和头部的能力对生存很重要。仅用眼睛跟踪是由视觉依赖和视网膜外机制控制的，后者在目标消光期间维持眼睛运动。我们研究了在头自由追求过程中，视网膜外成分在随机反应开始时是如何发展的，以及它如何与前庭眼反射（VOR）相互作用。受试者观看以相同速度成对出现的水平阶梯-斜坡刺激;速度在成对之间随机分布，范围从±5到40 deg s-1。在第一对（短斜坡消光）的目标是可见的，只有150毫秒。在第二（初始消光），经过一个随机固定期，目标是在运动开始熄灭，保持不可见的750毫秒，然后再出现的最后200毫秒的运动。受试者使用在短斜坡消光演示中获得的运动信息来跟踪从初始消光演示中看不见的运动开始的目标，使用视网膜外驱动来生成平滑的凝视和头部运动，以缩放到目标速度。注视速度上升更慢，比视觉驱动时，但有类似的时间发展，在头部自由和头部固定的条件。头部固定和头部自由状态下的头中眼速度差异与整个轨迹的头部速度密切相关，这意味着视网膜外驱动是在视觉缺失的情况下取消VOR的原因。因此，VOR在无头追踪期间显然保持活跃，增益接近1。还有证据表明，头部运动并不直接受视觉输入的控制，而是由类似于控制凝视的内部估计机制控制的。
In everyday life, we encounter moving objects and to follow them, we have developed smooth pursuit eye movements. When you rotate your head, the vestibulo-ocular reflex is activated, which generates compensatory smooth eye movements so your eyes remain focussed on the current object of interest. Previous work has shown that you can overcome this reflex to follow a moving object with your eyes and head together, but this normally requires visual feedback. The current study shows that under certain circumstances, for example when you can anticipate the motion of an object, you can use predictive mechanisms in the brain to supplement your pursuit movements to continue to follow the object if it disappears. We demonstrate that you can sample and store brief visual motion to pursue an unseen moving object. Additionally, you can more accurately follow it with your eyes and head together, compared to just using your eyes. The ability to co-ordinate the eyes and head when tracking moving objects is important for survival. Tracking with eyes alone is controlled by both visually dependent and extra-retinal mechanisms, the latter sustaining eye movement during target extinction. We investigated how the extra-retinal component develops at the beginning of randomised responses during head-free pursuit and how it interacts with the vestibulo-ocular reflex (VOR). Subjects viewed horizontal step-ramp stimuli which occurred in pairs of identical velocity; velocity was randomised between pairs, ranging from ±5 to 40 deg s−1. In the first of each pair (short-ramp extinction) the target was visible for only 150 ms. In the second (initial extinction), after a randomised fixation period, the target was extinguished at motion onset, remaining invisible for 750 ms before reappearing for the last 200 ms of motion. Subjects used motion information acquired in the short-ramp extinction presentation to track the target from the start of unseen motion in the initial extinction presentation, using extra-retinal drive to generate smooth gaze and head movements scaled to target velocity. Gaze velocity rose more slowly than when visually driven, but had similar temporal development in head-free and head-fixed conditions. The difference in eye-in-head velocity between head-fixed and head-free conditions was closely related to head velocity throughout its trajectory, implying that extra-retinal drive was responsible for countermanding the VOR in the absence of vision. Thus, the VOR apparently remained active during head-free pursuit with near-unity gain. Evidence also emerged that head movements are not directly controlled by visual input, but by internal estimation mechanisms similar to those controlling gaze.
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影响因子：
2.5
作者：
Barnes, G. R.;Collins, C. J. S.
通讯作者：
Collins, C. J. S.
影响因子：
2.5
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1.4
作者：
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2.5
作者：
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作者：
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