先天盲人“阅读”盲文的功能磁共振成像研究

Study of the congenital blind reading Braille in fMRI

目的利用磁共振功能成像显示先天盲生阅读盲文时大脑皮层的激活区,探讨盲生枕叶皮层的功能重组。方法实验组10例右利手先天盲生,分别执行盲文阅读和盲点鉴别任务。正常组大一学生10例,触摸盲文。FE-EPI采集,Medx3.2软件处理和分析,测定激活区范围和T值;比较盲人执行不同任务时和与正常组间的统计学差异。结果①10例盲生在阅读盲文时双侧主视皮层(V1)和辅助视皮层(V2、V3)激活。左右侧V1平均激活范围20和19个像素,左右侧(V2+V3)平均激活范围44和50个像素,(V2+V3)>V1。右侧(V1+V2+V3)平均激活范围69个像素,平均T值9.8;左侧平均激活范围64个像素,平均T值9;二者缺乏明显统计学意义。②盲生盲点鉴别时在双侧视皮层有散在小的激活簇,右侧(V1+V2+V3)平均激活范围16个像素,平均T值4.1;左侧平均激活范围12个像素,平均T值3.8;盲文阅读激活范围与T值同盲点鉴别任务比较有显著性差别,P<0.001。③盲生在盲文阅读时还显示以左侧为优势的两侧BA4、BA3、BA7及SMA(补充运动区)、左侧额下回激活。④正常组除了以左侧为优势的两侧BA4、BA3、左侧BA7及BA6激活外,视觉皮层没有激活。结论早期视觉剥夺盲人阅读盲文时视觉皮层激活,视觉皮层功能发生了重组,具有参与处理复杂文字语言的高级认知功能。

Objective Functional MRI was used to detect the cerebral activation areas during the congenital blind reading Braille, and to explore occipital cortical functional reorganization of the congenital blind. Methods Right-handed congenital blinds （n=10） performed the tasks of reading Braille and differentiation senseless dots. Freshmen as control group （n=10） performed the task of touching Braille. Acquisition of FE-EPI images. The data were acquired by FE-EPI sequence, processed and analyzed by the software of Medx 3.2. Results ①Primary visual cortex （V1） and supplementary visual cortex （V2,V3） in both sides were activated in the congenital blinds （n=10） during reading Braille. There was no significant difference between left and right V1. ②Activated clusters were dispersedly found in bilateral visual cortices during identifying senseless dots. Right total （V1＋V2＋V3） was 16 pixels, T value was 4. 1. Left total was 64 pixels, T value was 3.8. There was significant difference between reading Braille and identifying dots （P〈0. 001）. ③ Additional activated areas during reading Braille included BA4, BA3, BA7, SMA and left inferior frontal gyrus, and so on. ④During the control group touching Braille, no activation was found in the visual cortex, but activated areas were found in the two side areas, such as BA4, BA3, BA7, BA6 et al. Conclusion Reading Braille can result in the activation of visual cortex in patients with early visual deprivation. Functional reorganization may present in visual cortices, which may involve in the process of complex language cognition.