汉字与英文字形辨认的脑功能磁共振成像初步研究

目的:探讨功能磁共振成像(fMRI)技术研究人脑汉字与英文字形辨认方面的价值。材料与方法:12例(男5例,女7例)母语为汉语且裸眼视力正常的大学生参加实验。设备为GE Signa 1.5T MR仪,采用EPI序列,BOLD法行脑功能磁共振扫描。实验任务分别将汉字与英文(真字、假字、非字)投射到屏幕上,受试者通过头线圈反光镜观看屏幕并辨认。数据分析使用SPM 99升级软件,经过数据采集、预处理和建立模型显示结果。结果:汉字真字刺激在左额叶、中央前回(BA6)及枕叶(BA18)显著激活;左顶叶、中央后回(BA3)、右额下回(BA9)及双侧颞叶少量激活。英文真字刺激时左额中回、中央前回、左额下回显著激活;左颞梭状回(BA37)、右枕语言回(BA18)及左顶叶(BA40)也有激活。汉字和英文假字与非字只引起少量激活(P>0.05)。汉字与英文刺激左大脑半球的激活体积明显大于右半球;除枕叶外,英文在额、颞及顶叶引起的激活体积均大于汉字。结论:fMRI是研究人脑汉字和英文语言加工理想的无创性影像学方法,其脑加工优势半球均为左半球;母语为汉语者,其英文脑处理过程需更多的脑活动来参与和完成。

Preliminary fMRI study of human brain in identifying Chinese and English characters

Objective: To study the application values of functional magnetic resonance imaging(fMRI) in identifying and processing Chinese and English characters with human brain. Materials and Methods: Twelve students(5 males, 7 females), native Chinese speakers with normal sights participated in this study. fMRI examination were performed on GE Signa 1.5T MR system with EPI sequence. The tasks including Chinese and English characters(true word, false word, no word) were performed by the students identifying them projected on the screen through the reflector with the head coil. The data were collected on the basis of BOLD-MRI system and analyzed by SPM 99 to generate the brain activation map. Results: Chinese true word test showed significant activation in left frontal lobe, precentral gyrus(BA6), occipital lobe(BA18),and slight activation in left parietal lobe, postcentral gyrus(BA3), right inferior frontal gyrus(BA9) and bitemporal lobe;English true word test showed significant activation in left middle frontal gyrus, precentral gyrus, left inferior frontal gyrus,and also slight activating in left temporal fusiform gyrus(BA37), right occipital language gyrus(BA18) and left parietal lobe. Chinese and English false and no word test showed only little activation(P>0.05). It is showed that activation volume in left hemisphere of Chinese and English true word were larger than that of right hemisphere. The activating volume in frontal lobe, temporal lobe and parietal lobe of English true word were significantly larger than that of Chinese except the occipital lobe. Conclusions: fMRI is a feasible and non invasive imaging method for studying language processing in the human brain of Chinese and English words,the dominant hemisphere of processing languages is in the left. There are more brain areas to take part in and activate when native Chinese speakers processing English words.