The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex.
The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex.
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DOI：
10.1167/16.10.2
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发表时间：
2016-08-01
影响因子：
1.8
通讯作者：
Xu Y
中科院分区：
文献类型：
--
作者：
Jeong SK;Xu Y
人壁皮层表现出比对侧表现出的视觉刺激（即侧向）以及两个半球之间的不对称性偏爱，左侧顶层皮层表现出比右侧更大的侧向性。使用视觉短期记忆和感知任务以及目标位置可预测性，这项研究检查了半球横向性和不对称性是否是人壁皮层的固定特征半场。这里检查了两个顶部区域，这些区域以前已被证明与视觉对象个体化和识别有关，并分别位于下部和上部的内部沟（IPS）中。在三个实验中，在两个顶区域中发现了显着的侧向性，而不论注意力调制如何，在下较高的IP中，横向性分别与它们在对象个性化和识别中的作用一致。尽管自上而下的注意力的部署对上级IP没有影响，但下部IPS的侧向大大增加了。因此，自上而下的空间注意力的部署可以扩大下部IPS中侧向的强度。另一方面，在两个大脑区域中都没有半球不对称性，仅在上下降低注意力的情况下出现，但仅出现在上等的IP中。有趣的是，半球不对称的强度与下部IP的侧向强度显着相关。因此，半球不对称似乎只有在大脑区域中存在足够的横向性时才出现。
The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.