CAJ | 학술논문

利用功能性磁共振成像（fMRI）技术探讨文盲和非文盲汉字字形和语音加工脑机制的差异。实验1使用汉字字形和图形比较了中国人文盲和非文盲字形加工过程脑机制的左侧差异。实验2使用汉字语音和纯音比较了文盲和非文盲语音加工过程脑机制的双侧差异。结果表明文盲与非文盲汉字字形和语音加工脑机制不同，且非文盲的脑活动强。
이용공능성자공진성상（fMRI）기술탐토문맹화비문맹한자자형화어음가공뇌궤제적차이。실험1사용한자자형화도형비교료중국인문맹화비문맹자형가공과정뇌궤제적좌측차이。실험2사용한자어음화순음비교료문맹화비문맹어음가공과정뇌궤제적쌍측차이。결과표명문맹여비문맹한자자형화어음가공뇌궤제불동，차비문맹적뇌활동강。
Chinese is a logographic language system that differs from alphabetic languages, and some of the neurocognitive mechanisms underlying Chinese logographic reading also differ from those underlying alphabetic word reading （ Tan, 2000, 2001 ）. Previous studies that have compared performance between alphabetic/iterate and illiterate subjects indicate that the literates surpass the illiterates especially in tasks involving phonological processing and that the different activation regions in fMRI are located between Broca＇s area and the inferior parietal cortex as well as the posterior - midinsula bridge between Wernicke＇s and Broca＇s area. Few such studies were about Chinese -speaking individuals except one which showed different activation patterns between Chinese illiterates and literates in silent word recognition tasks （the left inferior/middle frontal gyrusand bilateral superior temporal gyri） and in silent picture - naming tasks （ the bilateral inferior/middle fontalgyri and left limbic cingulated gyms）. Our recent studies （ Wu, 2007 ; Cai, 2007 ） have found func- tional segregation in the left inferior frontal gyms, in which the dorsal regions are related to automatic access to an articulatory represen- tation at the syllable or phoneme level, and the ventral parts are related to lexical or semantic processing. However, it is still unknown whether education level effects the neural activation associated with the processing of Chinese. In this study, we used functional magnetic resonance imaging （fMRI） to investigate the effects of education level on brain activa- tion related to Chinese character font size and phonological processing of Chinese. Specifically, we designed two fMRI experiments with illiterate and literate subjects to assess the issue. In experiment 1, thirteen literate and thirteen illiterate subjects participatedin the visu- al Chinese characters and simple figures discrimination tasks. Subjects were asked to view the character or figure pairs and discriminate whether the characters or figures of each stimuli pair were the same or not using response keys. 289 fMRI volumes of images were col- lected during each run. Each fMRI run consisted of one task. An event - related design was used. Each pair of Chinese characters or figures was shown through the projector lasting for 4000ms, with an interpair interval of 2000ms, 4000ms or 6000ms between the stimu- li. Each task consisted of half Chinese characters and half figures. The eyes of the subjects were asked to fix on the crosshair all the time in order to avoid head movement. In experiment 2, the Chinese character voice and pure tone discrimination tasks were performed with twenty - six subjects （ 13 illiterates and 13 literates）. The subjects were also asked to press the response keys to discriminate whether the voice of characters or the pure tone pairs were the same or not. 145 fMRI volumes of images were collected during each run, which consisted of one task. An event - related design was used. Each pair of Chinese character voice or pure tone was shown through the projector lasting for lOOms, with an interpair interval of 5000ms between the stimuli. Each task consisted of 36 pairs of Chinese character voice and 36 pairs of pure tone. During MRI acquisition, the stimuli were presented using a custom - designed program on a personal computer （PC） and earphone outside the shielded room at the ear of the subject. The results of behavioral measurement and fMRI analysis showed stronger activations of Chinese literates than illiterates during lan- guage processing. In the experiment 1, we observed the brain network of Chinese character font size processing in the left middle frontal gyms （ BAg）, the left superior temporal gyrus （BA22） and the left inferior parietal gyrus （BA39）. In the experiment 2, we observed the brain network of Chinese phonological processing in the left middle frontal gyms （BA6）, the bilateral inferior frontal gyrus （BA47） , the bilateral superior temporal gyrus （BA21/22） , the left middle temporal gyrus （BA38） and the right inferior parietal gyms （BA40）. As conclusion, Chinese character has a different processing pattern than the English processing pattern in the human brain and literacy may affect brain plasticity by enhancing its cognitive valence during Chinese language processing.