Saccade control and eye-hand coordination in optic ataxia
Saccade control and eye-hand coordination in optic ataxia
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DOI：
10.1016/j.neuropsychologia.2007.08.028
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发表时间：
2008-01-01
期刊：
影响因子：
2.6
通讯作者：
Pisella, Laure
中科院分区：
文献类型：
--
作者：
Gaveau, Valerie;Pelisson, Denis;Pisella, Laure
本研究的目的是研究视神经共济失调（OA）患者的眼控制。在后顶叶皮层（PPC）病变后，这些患者表现出快速视觉运动控制的缺陷。在这里，我们评估了两名双侧OA患者的快速视觉运动控制以及自发的眼手协调，并采用生态“看和指”范式。为了检验快速扫视控制，与扫视开始同步的意外目标跳跃试验与静止目标试验随机混合。结果证实，控制组受试者与静止目标（快速扫视控制）在相同的时间内实现了位移目标的视觉捕捉（注视点），并在初级扫视结束时开始系统的手部运动。相比之下，两名双侧OA患者表现出视觉捕捉延迟，特别是移位目标，这是由于快速跳眼控制受损造成的。他们还表现出一种特殊的手眼协调模式，自发地将他们的手运动延迟到最后的纠正性扫视执行时，这允许目标注视。为了测试这种病态行为是否源于视觉目标位置更新的延迟，我们让受试者在相同的对照受试者中进行了第二次实验，其中目标跳跃与扫视偏移同步。在目标位置更新时间较短的情况下，对照组与OA患者表现出相同的快速跳眼控制缺失。我们认为OA对应于目标位置快速更新的损伤，因此影响眼和手的运动。(C) 2007 Elsevier Ltd.版权所有。
The aim of this work was to investigate ocular control in patients with optic ataxia (OA). Following a lesion in the posterior parietal cortex (PPC), these patients exhibit a deficit for fast visuo-motor control of reach-to-grasp movements. Here, we assessed the fast visuo-motor control of saccades as well as spontaneous eye-hand coordination in two bilateral OA patients and five neurologically intact controls in an ecological "look and point" paradigm. To test fast saccadic control, trials with unexpected target-jumps synchronised with saccade onset were randomly intermixed with stationary target trials. Results confirmed that control subjects achieved visual capture (foveation) of the displaced targets with the same timing as stationary targets (fast saccadic control) and began their hand movement systematically at the end of the primary saccade. In contrast, the two bilateral OA patients exhibited a delayed visual capture, especially of displaced targets, resulting from an impairment of fast saccadic control. They also exhibited a peculiar eye-hand coordination pattern, spontaneously delaying their hand movement onset until the execution of a final corrective saccade, which allowed target foveation. To test whether this pathological behaviour results from a delay in updating visual target location, we had subjects perform a second experiment in the same control subjects in which the target-jump was synchronised with saccade offset. With less time for target location updating, the control subjects exhibited the same lack of fast saccadic control as the OA patients. We propose that OA corresponds to an impairment of fast updating of target location, therefore affecting both eye and hand movements. (C) 2007 Elsevier Ltd. All rights reserved.