Human ocular pursuit during the transient disappearance of a visual target
Human ocular pursuit during the transient disappearance of a visual target
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DOI：
10.1152/jn.01145.2002
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发表时间：
2003-10-01
影响因子：
2.5
通讯作者：
Barnes, GR
中科院分区：
文献类型：
--
作者：
Bennett, SJ;Barnes, GR
在追踪移动目标的过程中，当目标在物体和表面后面移动时，经常会有短暂的消失时间。在实验环境中，眼球运动速度在运动目标消失时迅速衰减。然而，如果存在目标将沿着其轨迹进一步沿着再现的期望，则眼速度不会衰减到零。提高眼动速度以符合目标再现可以最小化显影速度误差，但这是否可以实现仍有待于经验验证。本研究的目的是研究刺激的可预测性，目标速度，和刺激间隔（ISI）的影响，在短暂的视觉目标消失的眼睛追求。我们证实，受试者（n = 9）没有保持眼速度接近目标速度的持续时间的ISI。一般而言，在眼速初始降低后，大多数受试者（n = 7）在目标再现前表现出显著增加。速度增加的时间不受目标速度，刺激的可预测性，或ISI。因此，对于900-ms ISI，增加过早发生，并且眼睛在目标再现的时刻减速。这些结果与目标消失时应用于视觉驱动的增益减少一致，随后是预期目标再现的重新激活。我们对这个过程进行了建模，使得增益在一个反馈系统中被调制，从而在没有负视觉反馈的情况下保留其输出，并在预期的目标再现之前实现预期的眼速增加。
During the course of pursuing a moving target there are often periods of transient disappearance as it moves behind objects and surfaces. In experimental settings, eye velocity decays rapidly on the extinction of a moving target. However, eye velocity does not decay to zero if there is an expectation the target will reappear further along its trajectory. Increasing eye velocity to coincide with target reappearance could minimize the developing velocity error, but it remains to be empirically verified whether this can be achieved. The aim of the present study was to examine the influence of stimulus predictability, target velocity, and interstimulus interval (ISI) on ocular pursuit during the transient disappearance of a visual target. We confirmed that subjects (n = 9) did not maintain eye velocity close to target velocity for the duration of the ISI. In general, after an initial reduction in eye velocity the majority of subjects (n = 7) exhibited a significant increase before target reappearance. The timing of the velocity increase was not influenced by target velocity, stimulus predictability, or ISI. Consequently, for the 900-ms ISI the increase occurred too early and the eye was decelerating at the moment of target reappearance. These results are consistent with a reduction in gain being applied to the visuomotor drive when the target disappeared, followed by a reactivation in expectation of target reappearance. We modeled this process such that gain was modulated within a reafferent feedback system, hence preserving its output in the absence of negative visual feedback and enabling an anticipatory increase in eye velocity before expected target reappearance.