Altered visual character and object recognition in Japanese-speaking adolescents with developmental dyslexia
Altered visual character and object recognition in Japanese-speaking adolescents with developmental dyslexia
复制标题
DOI：
10.1016/j.neulet.2020.134841
复制
发表时间：
2020-04-01
影响因子：
2.5
通讯作者：
Uno, Akira
中科院分区：
文献类型：
--
作者：
Higuchi, Hiroki;Iwaki, Sunao;Uno, Akira
许多研究已经证实，发展性阅读障碍（DD）患者的某些脑区存在功能障碍，包括左侧上级颞回和左侧梭状回。然而，日语阅读障碍患者的神经生物学基础尚未完全了解，主要是由于正字法系统的独特性。由于日语书面语的很大一部分包括语标汉字和表音假名系统，阅读障碍不仅可能是由于语音系统的功能障碍，而且可能是由于视觉识别系统的功能障碍。先前的研究报告改变了左枕颞叶皮层的层次视觉词形处理，但是，目前还不清楚是否改变了层次视觉处理语言刺激特异性。因此，我们的目的是调查是否（a）日语为母语的DD个体表现出非典型的层次视觉处理，如果是这样的话，（B）是否改变的层次视觉处理是语言刺激特异性或没有。本研究采用功能性磁共振成像技术，探讨了典型发育（TD）青少年和DD青少年汉字和物体刺激的层次成分的脑激活模式。对于汉字，DD青少年表现出更大的激活在左侧枕回和右侧枕梭状回，这种过度活跃也被发现为假汉字和人工汉字。这些结果意味着依赖于早期的视觉系统在日本语青少年与DD汉字阅读。此外，我们还研究了物体刺激的大脑活动，与TD青少年相比，DD青少年的双侧枕回显示出更大的激活。这些结果意味着改变的层次视觉加工的特点是过度激活的早期视觉区，这是一个不限于语言刺激。
Many studies have confirmed a brain dysfunction in people with developmental dyslexia (DD) in certain brain regions, including the left superior temporal gyrus and the left fusiform gyrus. However, the neurobiological substrates in Japanese-speaking people with dyslexia are not fully understood, mostly due to the uniqueness of the orthographic systems. Since a substantial part of the written Japanese includes the logographic Kanji as well as the phonographic Kana systems, the reading disability might be caused not only by a dysfunction in the phonological system, but also by a dysfunction in the visual recognition system. Previous studies reported altered hierarchical visual word form processing in the left occipitotemporal cortex; however, it remains unclear whether the altered hierarchical visual processing is language stimuli-specific. Therefore, we aimed to investigate whether (a) Japanese-speaking individuals with DD exhibit atypical hierarchical visual processing, and if so, (b) whether the altered hierarchical visual processing is language stimuli-specific or not. The present study investigated the brain activation pattern for the hierarchical component of the Kanji characters and object stimuli in typically developing (TD) adolescents and adolescents with DD using functional magnetic resonance imaging. For the Kanji characters, adolescents with DD showed a greater activation in the left occipital gyrus and right occipital fusiform gyrus, and this hyperactivity was also found for pseudo and artificial Kanji characters. These results imply reliance on an early visual system in Kanji reading in Japanese-speaking adolescents with DD. Additionally, we also investigated the brain activity for object stimuli, and adolescents with DD showed a greater activation in the bilateral occipital gyri compared with the TD adolescents. These results imply an altered hierarchical visual processing characterized by overactivation in the early visual areas, which is a not restricted to language stimulus only.