Cao Fan, Bitan Tali, Chou Tai-Li, Burman Douglas D, Booth James R
Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA.
J Child Psychol Psychiatry. 2006 Oct;47(10):1041-50. doi: 10.1111/j.1469-7610.2006.01684.x.
The current study examined the neuro-cognitive network of visual word rhyming judgment in 14 children with dyslexia and 14 age-matched control children (8- to 14-year-olds) using functional magnetic resonance imaging (fMRI).
In order to manipulate the difficulty of mapping orthography to phonology, we used conflicting and non-conflicting trials. The words in conflicting trials either had similar orthography but different phonology (e.g., pint-mint) or similar phonology but different orthography (e.g., jazz-has). The words in non-conflicting trials had similar orthography and phonology (e.g., gate-hate) or different orthography and phonology (e.g., press-list).
There were no differences in brain activation between the controls and children with dyslexia in the easier non-conflicting trials. However, the children with dyslexia showed less activation than the controls in left inferior frontal gyrus (BA 45/44/47/9), left inferior parietal lobule (BA 40), left inferior temporal gyrus/fusiform gyrus (BA 20/37) and left middle temporal gyrus (BA 21) for the more difficult conflicting trials. For the direct comparison of conflicting minus non-conflicting trials, controls showed greater activation than children with dyslexia in left inferior frontal gyrus (BA 9/45/46) and medial frontal gyrus (BA 8). Children with dyslexia did not show greater activation than controls for any comparison.
Reduced activation in these regions suggests that children with dyslexia have deficient orthographic representations in ventral temporal cortex as well as deficits in mapping between orthographic and phonological representations in inferior parietal cortex. The greater activation for the controls in inferior frontal gyrus could reflect more effective top-down modulation of posterior representations.
本研究采用功能磁共振成像（fMRI）对14名诵读困难儿童和14名年龄匹配的对照儿童（8至14岁）进行视觉单词押韵判断的神经认知网络研究。
为了操纵拼写与语音映射的难度，我们使用了冲突和非冲突试验。冲突试验中的单词要么拼写相似但语音不同（例如，pint - mint），要么语音相似但拼写不同（例如，jazz - has）。非冲突试验中的单词拼写和语音相似（例如，gate - hate）或拼写和语音不同（例如，press - list）。
在较简单的非冲突试验中，对照组和诵读困难儿童的大脑激活没有差异。然而，在较困难的冲突试验中，诵读困难儿童在左侧额下回（BA 45/44/47/9）、左侧顶下小叶（BA 40）、左侧颞下回/梭状回（BA 20/37）和左侧颞中回（BA 21）的激活比对照组少。对于冲突试验减去非冲突试验的直接比较，对照组在左侧额下回（BA 9/45/46）和额内侧回（BA 8）的激活比诵读困难儿童更大。在任何比较中，诵读困难儿童的激活都没有比对照组更大。
这些区域激活的减少表明，诵读困难儿童在腹侧颞叶皮质的拼写表征不足，以及在顶下皮质的拼写和语音表征之间的映射存在缺陷。对照组在额下回的更大激活可能反映了对后部表征更有效的自上而下的调节。
