Hoeft Fumiko, Hernandez Arvel, McMillon Glenn, Taylor-Hill Heather, Martindale Jennifer L, Meyler Ann, Keller Timothy A, Siok Wai Ting, Deutsch Gayle K, Just Marcel Adam, Whitfield-Gabrieli Susan, Gabrieli John D E
Department of Psychology, Stanford University, Palo Alto, California 94305-2130, USA.
J Neurosci. 2006 Oct 18;26(42):10700-8. doi: 10.1523/JNEUROSCI.4931-05.2006.
Adults and children with developmental dyslexia exhibit reduced parietotemporal activation in functional neuroimaging studies of phonological processing. These studies used age-matched and/or intelligence quotient-matched control groups whose reading ability and scanner task performance were often superior to that of the dyslexic group. It is unknown, therefore, whether differences in activation reflect simply poorer performance in the scanner, the underlying level of reading ability, or more specific neural correlates of dyslexia. To resolve this uncertainty, we conducted a functional magnetic resonance imaging study, with a rhyme judgment task, in which we compared dyslexic children with two control groups: age-matched children and reading-matched children (younger normal readers equated for reading ability or scanner-performance to the dyslexic children). Dyslexic children exhibited reduced activation relative to both age-matched and reading-matched children in the left parietotemporal cortex and five other regions, including the right parietotemporal cortex. The dyslexic children also exhibited reduced activation bilaterally in the parietotemporal cortex when compared with children equated for task performance during scanning. Nine of the 10 dyslexic children exhibited reduced left parietotemporal activation compared with their individually selected age-matched or reading-matched control children. Additionally, normal reading fifth graders showed more activation in the same bilateral parietotemporal regions than normal-reading third graders. These findings indicate that the activation differences seen in the dyslexic children cannot be accounted for by either current reading level or scanner task performance, but instead represent a distinct developmental atypicality in the neural systems that support learning to read.
在音韵加工的功能性神经成像研究中，患有发展性阅读障碍的成人和儿童表现出顶颞叶激活减少。这些研究使用了年龄匹配和/或智商匹配的对照组，其阅读能力和扫描仪任务表现通常优于阅读障碍组。因此，尚不清楚激活差异是否仅仅反映了在扫描仪中的表现较差、潜在的阅读能力水平，或者是阅读障碍更具体的神经关联。为了解决这一不确定性，我们进行了一项功能性磁共振成像研究，采用押韵判断任务，将阅读障碍儿童与两个对照组进行比较：年龄匹配的儿童和阅读匹配的儿童（阅读能力或扫描仪表现与阅读障碍儿童相当的较年轻正常读者）。与年龄匹配和阅读匹配的儿童相比，阅读障碍儿童在左侧顶颞叶皮层和其他五个区域（包括右侧顶颞叶皮层）的激活减少。与扫描过程中任务表现相当的儿童相比，阅读障碍儿童在顶颞叶皮层的双侧激活也减少。10名阅读障碍儿童中有9名与其各自选择的年龄匹配或阅读匹配的对照儿童相比，左侧顶颞叶激活减少。此外，正常阅读的五年级学生在相同的双侧顶颞叶区域比正常阅读的三年级学生表现出更多的激活。这些发现表明，阅读障碍儿童中观察到的激活差异不能用当前的阅读水平或扫描仪任务表现来解释，而是代表了支持学习阅读的神经系统中一种独特的发育异常。
