汉字视听再认的ERP效应与记忆提取脑机制

ERP EFFECTS OF RECOGNITION OF CHINESE SPOKEN AND WRITTENWORDS AND NEURAL MECHANISM OF RETRIEVAL

测定了正常青年人汉字再认的事件相关电位 (ERP)。观察到对听觉汉字的认知产生“持续中央负成分” ,而视觉汉字的认知出现“晚期正成分” ,提示汉字的视听认知具有不同的脑机制。汉字视听认知皆出现了新旧效应 ,即旧词皆引起ERP晚期成分的正走向变化 ,但视听新旧效应的起始时间与头皮分布不同 ,听觉效应为右半球优势 ,视觉效应则出现在左侧顶叶、左侧颞叶后部与右侧枕叶。以上实验结果提示 ,“优势半球”概念已难以概括半球间的多维动态关系 。

Event related potentials were recorded while 13 normal young subject s (age range 23 32 years) were recognizing Chinese words presented in either aud i tory or visual modality. The 'sustained central negativity' (SCN) elicited by sp oken words and the 'late positive component' (LPC) evoked by written ones were observed, this suggested different retrieval mechanism between them. The old/new effect was significant for both recognition of written and spoken Chines e characters, that is, the old items yielded more positive going ERP components than did the new items. However, the effect in the sound recalling is dominant o ver the right hemisphere and that for the written words distributes at the left parietal , po sterior temporal scalp and right occipital area. The result of the present exper imen t proposes the concept that the 'dominant hemisphere' is hard to conclude the mu ltidimensional and dynamic relationship between hemispheres and it is necessary to be modified.