Investigating the site of human saccadic adaptation with express and targeting saccades
Investigating the site of human saccadic adaptation with express and targeting saccades
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DOI：
10.1007/s00221-002-1077-x
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发表时间：
2002-06-01
影响因子：
2
通讯作者：
Fuchs, AF
中科院分区：
文献类型：
--
作者：
Hopp, JJ;Fuchs, AF
为了专注于视觉环境中的各种感兴趣的物体，灵长类动物使用称为扫视的快速眼球运动。当这些动作的准确性受损时，大脑可以通过一个称为扫视适应的过程来调整它们的幅度。为了研究人脑中这种可塑性的位置，我们在行为上调整了两种类型的眼跳，认为它们是通过不同的神经元路径产生的。靶向眼跳是为了顺次照亮目标，潜伏期很长，被认为涉及更高的皮质处理，而潜伏期非常短的快速眼跳显然并非如此。如果适应在这两种类型的眼跳之间转移，人们可能会得出结论，可塑性肯定存在于产生这两种眼跳的两条路径共同的位置。我们通过将TAR(让其三分之一的幅度回到初始注视位置)内移动TAR来直接降低靶向或快速眼跳的增益，然后检查其他类型的眼跳是否也降低了增益。当直接调整目标性眼跳时，所有受试者的眼跳增益都显著降低。在所有受试者的32个实验目标条件中，75%的人快速眼跳的收益也显著减少，从而提供了适应转移的证据。在这些条件中的71%(即所有目标条件的53%)，两种类型的眼跳的增益降低之间没有显著差异，这表明适应转移已经完成(100%)。当直接适应快速眼跳时，也得到了类似的结果：91%的快速眼跳和100%的靶向眼跳的增益显著降低。在86%的目标条件下，在不同受试者中，快速扫视和靶向扫视都显示增益显著降低，这两种类型的扫视在增益减少量上没有显著差异。这表明适应转移已经完成了所有目标条件的78%。因此，我们得出结论，眼跳适应在靶向眼跳和快速眼跳之间有很强的传递。这些结果表明，人类的适应发生在产生这两种眼跳的通路汇合之后，可能在上丘或在上丘下游。
To focus on various objects of interest within the visual environment, primates employ rapid eye movements called saccades. When the accuracy of these movements becomes impaired, the brain can adjust their amplitude by a process known as saccadic adaptation. To investigate the locus of this plasticity in the human brain, we behaviorally adapted two types of saccade thought to be generated through different neuronal pathways. Targeting saccades, which are made to sequentially illuminated targets and have long latencies, are thought to involve higher cortical processing whereas express saccades, which have very short latencies, apparently do not. If adaptation transfers between these two types of saccade, one may conclude that the plasticity must exist at a locus common to the two pathways generating these saccades. We directly reduced the gain of either targeting or express saccades by intrasaccadically moving the tar(let one-third of its amplitude back toward the initial fixation location and then examined whether the gain was also reduced in the other type of saccade. When targeting saccades were adapted directly, all subjects showed significant reductions in the gain of these saccades. In 75% of the 32 experimental target conditions across all subjects, there were also significant reductions in the gain of express saccades, thus providing evidence of adaptation transfer. In 71% of these conditions (i.e., 53% of all target conditions) there was no significant difference between the reductions in gain of the two types of saccade, suggesting that adaptation transfer was complete (100%). Similar results were obtained when express saccades were adapted directly: significant reductions in gain occurred in 91% of express saccades and in 100% of targeting saccades. In 86% of the target conditions, across subjects, in which both express and targeting saccades showed significant reductions in gain, the two types of saccade did not differ significantly in the amount of gain reduction. This suggests that adaptation transfer was complete for 78% of all target conditions. Therefore, we conclude that saccadic adaptation transfers robustly between targeting and express saccades. These results suggest that adaptation in humans occurs after the pathways generating these two types of saccade converge, probably at or downstream from the superior colliculus.