Shaywitz S E, Shaywitz B A, Pugh K R, Fulbright R K, Constable R T, Mencl W E, Shankweiler D P, Liberman A M, Skudlarski P, Fletcher J M, Katz L, Marchione K E, Lacadie C, Gatenby C, Gore J C
Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA.
Proc Natl Acad Sci U S A. 1998 Mar 3;95(5):2636-41. doi: 10.1073/pnas.95.5.2636.
Learning to read requires an awareness that spoken words can be decomposed into the phonologic constituents that the alphabetic characters represent. Such phonologic awareness is characteristically lacking in dyslexic readers who, therefore, have difficulty mapping the alphabetic characters onto the spoken word. To find the location and extent of the functional disruption in neural systems that underlies this impairment, we used functional magnetic resonance imaging to compare brain activation patterns in dyslexic and nonimpaired subjects as they performed tasks that made progressively greater demands on phonologic analysis. Brain activation patterns differed significantly between the groups with dyslexic readers showing relative underactivation in posterior regions (Wernicke's area, the angular gyrus, and striate cortex) and relative overactivation in an anterior region (inferior frontal gyrus). These results support a conclusion that the impairment in dyslexia is phonologic in nature and that these brain activation patterns may provide a neural signature for this impairment.
学习阅读需要意识到口语单词可以分解为字母字符所代表的语音成分。诵读困难的读者通常缺乏这种语音意识，因此他们在将字母字符映射到口语单词上存在困难。为了找到导致这种障碍的神经系统功能紊乱的位置和程度，我们使用功能磁共振成像来比较诵读困难和未受影响的受试者在执行对语音分析要求逐渐提高的任务时的大脑激活模式。两组之间的大脑激活模式存在显著差异，诵读困难的读者在后部区域（韦尼克区、角回和纹状皮质）表现出相对激活不足，而在前部区域（额下回）表现出相对激活过度。这些结果支持了这样一个结论，即诵读困难的障碍本质上是语音方面的，并且这些大脑激活模式可能为这种障碍提供神经特征。
