The Processing of Semantic Meaning in Chinese Words and Evoked Brain Topography

The connotative meaning of words can be quantified statistically by the "semantic differential technique" resulting in statistically defined, independent dimensions where every word is uniquely located on the three dimensional evaluation. In an earlier study on German subjects we demonstrated that there are electrophysiological correlates of these meaning dimensions. Here a group of 55 Chinese adults was investigated in two experiments: first, 210 nouns were rated by 32 subjects, and factor analysis on the questionnaire data yielded three independent semantic dimensions. Semantically unique words stemming from these results were then used as stimuli in electrophysiological experiments in another group of 23 healthy right-handed adults. Words of similar physical appearance belonging to different semantic classes were presented visually in random order. The EEG was recorded from 29 channels, and evoked brain activity was computed for each semantic class. Significant differences in electrical brain activation between these semantic word classes were observed as early as 80 ms after stimulus onset, confirming earlier reports on similar findings in German subjects. Further similarities were revealed by a direct comparison of the topographical distribution of potential components elicited by words, and by the results of spatial PCA performed on both sets of data. These results illustrate similar early neural activation based on semantic class, in subject groups of different language and culture.