Abstract: The Representation of Chinese Two-character Words in Mental Lexicon:Evidence from an fNIRS Study Abstract: The representation and processing of compound words in mental lexicon is an important topic of cognitive psychology.By studying on processing of compound words words,it can answer the question that a representation term of compound words in the mental is word or polymorphemic. At present,there are three models about the representation and processing of compound words, including morpheme representation model,word representation model,mixed representation model.According to Morpheme representation model, a representation term is a polymorphemic;Word representation model suggests a representation term is a word; According to mixed representation model,for familiar words, a representation term is a word,while for pseudowords which no representation words in mental lexicon , a representation term only is a polymorphemic. These years,brain imaging provides a critical tool for investigating the role of polymorphemic processing and its neural basis.By functional neuroimaging studies on processing of comound words and pseudowords to test different cognitive models of reading words. However, sevearl studies comparing words and pseudowords have produced inconsistent results. The inconsistencies could reflect confounds from non lexical aspects of the stimuli.Alternatively, they may reflect true effects that are inconsistent across subjects, different subjects may use different reading strategies; dependent on experimental design such as block or slow event-related design; or not replicated across studies because of insufficient statistical power. Functional near-infrared spectroscopy (fNIRS) has become increasingly established as a promising technique for monitoring functional brain activity.With the use of the general linear model (GLM) for fNIRS data analysis, rapid event-related designs have been incorporated in fNIRS studies. This method is a reliable tool to investigate visual word recognition. The present study examined cortical oxygenation changes while twenty-two right-handed healthy native Chinese speaking college students pefermed visual lexical decision on 96 words and 96 pseudwords using functional Near-Infrared Spectrosopy (fNIRS). Sources (n = 11) and detectors (n = 10) were placed left frontal, left temporal associated with language-related processes regions.The behavioral results shows there was a signifcant lexically effect in RTs, pseudowords were significantly slower than real words.However,non signifcant for the mean average error. And fNIRS data shows that the processing real words and pseudowords activated the same set of regions relative to fixation, and this system including superior frontal gyrus, middle frontal gyurs,superior temporal gyrus, middle temporal gyurs.However, superior frontal gyrus, middle frontal gyurs, was significantly more activated in real word processing than in pseudowords processing.The result indicated that a highly comparable neural network were involved with word processing;frontal temporal work network were involved during visual lexical decision on words and pseudwords which may in relation to semantic processing,left frontal lobe in lexical decision may executive the selection of semantic, is real time to get the semantic information. All the findings supported that the mixed representation model could account for the structure of the access representation of Chinese Two-character words in mental lexicon.The present research provide a neuroimaging evidence for the mixed representation model.

Key words: visual lexical decision, fNIRS, lexical representation

摘要： 摘 要 以汉语双字构成的真词与假词为实验材料，22名大学生为被试，采用功能性近红外脑成像技术（fNIRS）和事件相关设计，考察被试在完成词汇判断任务时的大脑激活模式，探索汉语双字词在心理词典中的表征方式。结果发现：（1）在完成真假词判断任务时，被试大脑左侧额叶和左侧颞叶均被激活；（2）与判断假词相比，被试在判断真词时显著地激活左额上回和左额中回。这一结果说明汉语双字词在心理词典中是混合表征的。

关键词: 双字词 词汇判断任务 功能性近红外脑成像技术 表征方式