Centro-parietal N200: An event-related potential component specific to Chinese visual word recognition

Abstract

Almost all written languages currently used in the world are alphabetic or phonologically-based scripts (e.g., English) whose word recognition involves discrimination of one-dimensional linear combinations of several dozens of letters or phonological units, except written Chinese whose vocabulary consists of a large number of block characters, the analysis of which relies on the extraction of 2-dimensional form information at multiple levels including radical, character, and multiple-character word. Whether the dramatic contrast between the 2 types of orthography leads to distinctive mental processes is a fundamental question in psycholinguistic research unanswered in the past three decades. Using event-related potentials and visual lexical decision tasks, we asked native Chinese speakers to discriminate between real Chinese words and pseudo-or non-words and observed a widespread negative deflection with centro-parietal focus elicited 200 ms post-stimulus onset. This N200 response showed a clear and large amplitude enhancement upon word repetition and seems to be specific to Chinese as no similar effects had been reported in word recognition studies involving alphabetic scripts under similar experimental conditions. Further evidence showed that this N200 could not be attributed to non-linguistic sensori-perceptual processes, nor phonological or semantic processes, but likely reflects very early identification of the orthography of individual words involving extensive and higher-level visual analysis. Recently the first author proposed a meaning-spelling theory of written Chinese vocabulary proposing that the Chinese and alphabetic scripts are the only 2 possible logical types of mature human writing systems, and that the former is more thoroughly a visual language compared with the latter and thus shall emphasize more of visual processing. Reinforcing each other, the meaning-spelling theory and the discovery of the centro-parietal N200 reveal the uniqueness of Chinese both theoretically and empirically, and provide strong arguments for the intrinsic distinction between written Chinese and alphabetic scripts.

ERP evidence for the time course of mental rotation in the mirror reading of Chinese words

“…Compared with reversed words, normal words elicited a more negative N200. Based on its polarity, latency, and scalp distribution, this component is very likely the centro-parietal N200 known to reflect word form processing in two-character Chinese word recognition [23] and can therefore be connected with the N2 for single-characters [24]. The reduced N200 for the reversed words indicates that form recognition had not been fully completed for the reversed words in this time window.…”

“…Statistical analyses of the ERP effects included several repeatedmeasures ANOVAs with mean amplitude values computed for each participant and each electrode in three time windows: (a) 170-210 ms for N200 (i.e., the N2 for two-character words [23]), (b) 300-400 ms for N400, (c) 400-550 ms for LPC. For each time window, the results were analyzed in an ANOVA across the two levels of the word type factor (normal and reversed) with 9 levels of the electrode factor.…”

Single-trial decoding of imagined grip force parameters involving the right or left hand based on movement-related cortical potentials

“…However, unlike BCIs which are based on event-related potentials evoked by external stimulations such as visual and auditory stimuli (including a hybrid BCIs based on the combination of two different external stimuli, such as P300 and SSVEP) [5][6][7][8][9], BCIs based on imagined movement involve endogenously induced potentials [10][11][12][13]. Potentials evoked by external stimuli have more distinctive and stable features than those endogenously induced by internal events [14,15]. Feature representation for imagined grip force MRCP involving the right or left hand was evaluated, and imagined grip force parameters based on EEG activity from a single-trial EEG were decoded in order to further explore the features of endogenously induced potentials.…”

Neural evidence for direct meaning access from orthography in Chinese word reading

“…We attributed this superiority of the mediated pathway in English to a fundamental design principle of the alphabetical wring systems -the systematic rules in English that map letter strings to sounds, allowing efficient print-to-phonology access (Harm and Seidenberg, 2004;Perfetti et al, 2005). In comparison, lack of such rules in Chinese leads to a weak mediated pathway that has to be compensated for with a strengthened direct pathway emphasizing orthographic processing (Zhang, 2011;Zhang et al, 2012). Such strengthening is expected to occur gradually as reading develops and offers more opportunity to establish the connection between orthography and semantics.…”