摘要目的 探索对汉字部件空间信息进行分析的特殊脑区,探讨视觉空间辨别能力与汉字部首的辨别之间的关系,为进一步探讨汉语阅读障碍的神经机制提供依据.方法 选择广州市某小学四、五年级正常健康学龄9名(男7例,女2例)为研究对象,年龄10～11岁,母语为汉语,右利手.使用Siemens 3.0 T磁共振扫描仪,采用单次激发平面回波扫描序列和组块设计的刺激模式,采用图形开口方向辨别和汉字部首辨别任务,对被试进行脑功能磁共振扫描,采集全脑的fMRI数据.使用SPM2软件包进行数据处理,分别获得2种任务刺激和对照刺激对比的脑激活图.结果 被试在2个实验任务中的反应时均比对照反应时要长,差异有显著性[(879±127)ms,(805±124)ms,P=0.029;(917±144)ms,(750±101)ms,P＜0.01];对照与任务的反应正确率差异无显著性[(96±5)%,(95±8)%,P=0.515;(89±10)%,(96±6)%,P=0.130].在完成图形开口方向辨别任务时,被试双侧顶下回、右侧顶上回、右侧楔前叶及枕叶皮层出现激活.在完成汉字部首辨别任务时,被试左侧楔前叶、左侧顶上回、右侧中央前回、右侧额下回、左侧海马、右侧丘脑、右侧尾状核及枕叶的多个皮层出现激活.结论 右侧大脑半球为图形开口方向辨别的优势半球,左侧大脑半球为汉字部首辨别的优势半球,汉字偏旁的辨别与图形开口方向的辨别之间存在部分类似的机制,视觉空间方向的辨别能力可能是汉字部首辨别所需的一种基本能力.

abstractsObjective To explore the specific brain regions involved in Chinese character radicals visualspatial processing,as well as to explore the relationship between visual-spatial identification and Chinese characters radicals identification.To provide an evidence for understanding the underlying neural mechanism of developmental dyslexic.Methods Twelve healthy Chinese fourth and fifth grade children(7 boys and 2 girls,aged from 10 to 11 years old)were chosen from a primary school in Guangzhou.The children were native Chinese speakers and right handed.The subjects participated in two fMRI experiments on a 3.0 T Siemens MR scanner.Two separate block-designed cognitive tasks were devised,one was figure directions judgement task and the other was Chinese characters radical identification task.A single-shot GE-EPI scan sequence were used for fMRI scans.The BOLD fMRI data were collected and were preprocessed and analyzed in SPM2.Results The subjects had longer reaction time during the two experiments tasks than in control states((879±127)ms vs(805±124)ms,P=0.029;(917±144)ms vs(750±101)ms,P＜0.01),and had same response accuracy in both tasks and control states((96±5)% vs(95±8)%,P=0.515;(89±10)% vs(96±6)%,P=0.130).In figure direction judgement experiment,activations were found in bilateral occipital,right superior parietal,right precuneus and right middle frontal cortices.However,different and more extensive regions including left superior parietal,left precuneus,left hippocampus,right thalamus,right caudate cortices and bilateral occipital cortices were involved in identifying the radicals of Chinese characters.Conclusion Right hemisphere was dominant in judging the figure direction,and left hemisphere is dominant in identifying radicals of Chinese characters.These fMRI results show light on underlying partial similar neurophysiological mechanism between judging figure directions and identifying Chinese character radicals.The visual-spatial ability may be essential for Chinese character radical identification.