Orthographic processing deficits in developmental dyslexia: Beyond the ventral visual stream
Orthographic processing deficits in developmental dyslexia: Beyond the ventral visual stream
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DOI：
10.1016/j.neuroimage.2016.01.014
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发表时间：
2016-03-01
期刊：
影响因子：
5.7
通讯作者：
Ziegler, Johannes C.
中科院分区：
文献类型：
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作者：
Boros, Marianna;Anton, Jean-Luc;Ziegler, Johannes C.
快速轻松的阅读与视觉词形区（VWFA）有关，VWFA是腹侧视觉流中专门识别字母串的区域。几项关于阅读障碍的神经影像学研究显示，这一区域的激活不足。然而，这些研究大多使用阅读任务和/或在成人身上进行。鉴于流利的阅读在阅读障碍者中受到严重损害，任何激活不足可能只是反映了受损读者中公认的阅读缺陷，并且可能是阅读障碍的后果而不是原因。在这里，我们设计了一个任务，它不依赖于阅读本身，而是利用形成阅读基础的早期视觉正字法处理。阅读障碍儿童年龄在8-12岁和年龄匹配的控制被要求搜索的字母，数字和符号的5个元素的字符串（实验1）。这个新的任务是由一个经典的任务激活VWFA，即被动观看的pseudowords和falsefonts（实验2）。我们发现，除了在VWFA显着的组间差异，睡眠障碍儿童表现出显着的枕中回（MOG）相对于对照组的激活不足。MOG中的几个区域因其参与视觉空间处理而闻名，并且已经提出MOG对于将不熟悉的字符串中的符号排序是必要的。我们的研究结果表明，VWFA赤字可能是次要的视觉空间处理在MOG的损害。我们认为，在阅读习得过程中，MOG的有效加工对于VWFA中轻松快速的视觉单词识别的发展至关重要。(C)2016 Elsevier Inc. All rights reserved.
Fast effortless reading has been associated with the Visual Word Form Area (VWFA), a region in the ventral visual stream that specializes in the recognition of letter strings. Several neuroimaging studies of dyslexia revealed an underactivation of this region. However, most of these studies used reading tasks and/or were carried out on adults. Given that fluent reading is severely impaired in dyslexics, any underactivation might simply reflect a well-established reading deficit in impaired readers and could be the consequence rather than the cause of dyslexia. Here, we designed a task that does not rely on reading per se but that tapped early visual orthographic processing that forms the basis of reading. Dyslexic children aged 8-12 years and age-matched controls were asked to search for letters, digits, and symbols in 5-element strings (Experiment 1). This novel task was complemented by a classic task known to activate the VWFA, namely the passive viewing of pseudowords and falsefonts (Experiment 2). We found that in addition to significant group differences in the VWFA, dyslexic children showed a significant underactivation of the middle occipital gyrus (MOG) relative to the control group. Several areas in the MOG are known for their engagement in visuospatial processing, and it has been proposed that the MOG is necessary for ordering the symbols in unfamiliar strings. Our results suggest that the VWFA deficit might be secondary to an impairment of visuospatial processing in the MOG. We argue that efficient processing in MOG in the course of reading acquisition is critical for the development of effortless fast visual word recognition in the VWFA. (C) 2016 Elsevier Inc. All rights reserved.