Cortical control of visually guided reaching: Evidence from patients with optic ataxia
Cortical control of visually guided reaching: Evidence from patients with optic ataxia
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DOI：
10.1093/cercor/bhi034
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发表时间：
2005-10-01
期刊：
影响因子：
3.7
通讯作者：
Perenin, MT
中科院分区：
文献类型：
--
作者：
Karnath, HO;Perenin, MT
连接V1和顶叶皮层的视觉信息处理的背侧流被认为提供了视觉引导到达的快速控制。对于这一假设来说，重要的是观察到，在猴子和人类中，顶叶损伤可能会引起视觉目标导向的手部运动的干扰。在人类中，被称为“视神经共济失调”的严重失伸被归因于顶叶上小叶（SPL）和/或顶叶内沟的病变。使用新的病变分析工具，在这里，我们重新评估了这一观点，调查了15年来收集的大量单侧卒中伴视神经共济失调患者的典型病变位置。我们没有发现任何证据表明，人类视觉引导触达的中断与典型的以SPL为中心的凸性病变有关。在左半球和右半球中，我们发现视神经失调与病变重叠相关，病变重叠影响枕顶交界处的外侧皮质凸度，即下顶叶（IPL）和枕上皮层之间的交界处，在左半球甚至更后方，也影响枕皮质和SPL之间的交界处。通过顶叶下的白质，病变重叠在两个半球延伸到内侧皮层，在那里它影响了靠近枕顶交界处的楔前叶。这些外侧和内侧结构似乎是人类视觉引导伸手快速控制的组成部分。
The dorsal stream of visual information processing connecting V1 to the parietal cortex is thought to provide a fast control of visually guided reaching. Important for this assumption was the observation that in both the monkey and the human, parietal lesions may provoke disturbance of visually goal-directed hand movements. In the human, severe misreaching termed 'optic ataxia' has been ascribed to lesions of the superior parietal lobule (SPL) and/or the intraparietal sulcus. Using new tools for lesion analysis, here we re-evaluated this view investigating the typical lesion location in a large group of unilateral stroke patients with optic ataxia, collected over a time period of 15 years. We found no evidence for the assumption that disruption of visually guided reaching in humans is associated with a lesion typically centering on the SPL on the convexity. In both left and right hemispheres, we found optic ataxia associated with a lesion overlap that affected the lateral cortical convexity at the occipito-parietal junction, i.e. the junction between the inferior parietal lobule (IPL) and superior occipital cortex and - in the left hemisphere even more posteriorly - also the junction between occipital cortex and the SPL. Via the underlying parietal white matter, the lesion overlap extended in both hemispheres to the medial cortical aspect, where it affected the precuneus close to the occipito-parietal junction. These lateral and medial structures seem to be integral to the fast control of visually guided reaching in humans.