Effects of semantic discrimination of Chinese words on N400 component of event-related potentials

20 subjects' event-related brain potentials ii ere measured during a lexica l decision task in which Chinese characters were used in both conditions of related (antonym) and unrelated words. Analysis indicated that the mean re action time for unrelated words was 130 msec. longer than that elicited by related words. The condition of unrelated words elicited a significant N450 , and an obvious P500 was evoked by related words at each of the 17 recordi ng sites. Furthermore, the amplitudes of N210 and N450 were larger in the l eft hemisphere than in the right hemisphere but the amplitude of P500 was l arger in the right hemisphere than in the left hemisphere.