title: N400 elicited by incongruent ending words of Chinese idioms in healthy adults.
abstract: BACKGROUND
  Prior research about N400 has been mainly based on English stimuli, while the cognitive processing of Chinese characters is still unclear. The aim of the present study was to further investigate the semantic processing of Chinese idioms.
  
  
  METHODS
  Event related potentials (ERP) component N400 was elicited by 38 pairs of matching (congruent) and mismatching (incongruent) ended Chinese idioms: ending words with same phoneme but different shape and meaning (sPdSdM), with similar shape but different phoneme and meaning (sSdPdM), with same meaning but different phoneme and shape (sMdPdS), and words with different phoneme, shape and meaning (dPdSdM) and recorded by Guangzhou Runjie WJ-1 ERP instruments. In 62 right-handed healthy adults (age 19 - 50 years), N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz, Cz and Pz.
  
  
  RESULTS
  N400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz. The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending words in healthy adults. Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-words idioms in healthy adults (P < 0.05). Compared with matching ending-words idioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones. N400s elicited by different types of stimuli showed different latencies and amplitudes, and longest N400 latency and largest N400 amplitude were elicited by ending-words with dPdSdM. No gender difference was found of N400 latency and amplitude in this study (P > 0.05).
  
  
  CONCLUSIONS
  Compared with English stimuli, Chinese ideographic words could provide more flexible stimuli for N400 research in that the words have 3-dimension changes - phoneme, shape and meaning. Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the word. Some issues of N400 elicited by Chinese characters deserve further research.
authors.affiliation: Department of Electrophysiology, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Xing-shi
authors.initials: XS
authors.lastname: Chen
authors.forename: Yun-xiang
authors.initials: YX
authors.lastname: Tang
authors.forename: Ze-ping
authors.initials: ZP
authors.lastname: Xiao
authors.forename: Ji-jun
authors.initials: JJ
authors.lastname: Wang
authors.forename: Ming-dao
authors.initials: MD
authors.lastname: Zhang
authors.forename: Zai-fu
authors.initials: ZF
authors.lastname: Zhang
authors.forename: Zhen-yu
authors.initials: ZY
authors.lastname: Hu
authors.forename: Fei-ying
authors.initials: FY
authors.lastname: Lou
authors.forename: Chong
authors.initials: C
authors.lastname: Chen
authors.forename: Tian-hong
authors.initials: TH
authors.lastname: Zhang
mesh_terms: D000328:Adult; D003071:Cognition; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time; D011932:Reading; D012660:Semantics; D012727:Sex Characteristics