Cortical effects of shifting letter position in letter strings of varying length
Cortical effects of shifting letter position in letter strings of varying length
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DOI：
10.1162/jocn.2003.15.5.731
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发表时间：
2003-07-01
影响因子：
3.2
通讯作者：
Salmelin, R
中科院分区：
文献类型：
--
作者：
Cornelissen, P;Tarkiainen, A;Salmelin, R
神经成像和损伤研究表明，枕颞区在识别各种各样的物体方面发挥着必要的作用，无论是人脸、字母、数字还是家居用品。然而，关于枕颞叶皮质到底处理哪些类型的信息的细节，仍然存在许多问题。在这里，我们从阅读的角度来解决这个问题。10名健康的成年受试者完成了一项单一的单词阅读任务。我们使用全头脑磁图来测量大脑反应的时空动态，并研究它们对：(1)词汇性(这里定义为单词和辅音串之间的差异)、(2)单词长度和(3)字母位置变化的敏感性。分析表明，100毫秒左右的枕中线活动与低水平的视觉特征分析一致，对词汇性和字母位置的变化不敏感，但受字符串长度的影响较小。大约150毫秒左右的双侧枕叶激活对词汇性不敏感，只在激活的时间(而不是强度)对词长做出反应。然而，字母位置的垂直移动显示了大脑半球的不平衡：右脑的激活随着移动的增加而增加，而左半球的情况则相反。根据Caramazza和Hillis(1990)的早期阅读模型对结果进行了讨论。
Neuroimaging and lesion studies suggest that occipitotemporal brain areas play a necessary role in recognizing a wide variety of objects, be they faces, letters, numbers, or household items. However, many questions remain regarding the details of exactly what kinds of information are processed by the occipito-temporal cortex. Here, we address this question with respect to reading. Ten healthy, adult subjects performed a single word reading task. We used whole-head magnetoencephalography to measure the spatio-temporal dynamics of brain responses, and investigated their sensitivity to: (1) lexicality (defined here as the difference between words and consonant strings), (2) word length, and (3) variation in letter position. Analysis revealed that midline occipital activity around 100 msec, consistent with low-level visual feature analysis, was insensitive to lexicality and variation in letter position, but was slightly affected by string length. Bilateral occipito-temporal activations around 150 msec were insensitive to lexicality and reacted to word length only in the timing (and not strength) of activation. However, vertical shifts in letter position revealed a hemispheric imbalance: The right hemisphere activation increased with the shifts, whereas the opposite pattern was evident in the left hemisphere. The results are discussed in the light of Caramazza and Hillis's (1990) model of early reading.