Objective To investigate the use of component N400 of the event-related potentials (ERPs) elicited by Chinese idioms ending with matching and nonmatching words to explore the cognitive patterns and processing mechanisms elicited by Chinese characters. Methods Sixty-two right-handed healthy adults (age 19-50 years) , were presented with Chinese idioms ending with words with the same pronunciation but different form and meaning, words with similar forms but different pronunciation and meaning, words with same meaning but different pronunciation and form, and words with different pronunciation, form and meaning. A Guangzhou Runjie WJ-1 instrument was used to record component N400 of the potentials evoked. Results N400 showed a midline distribution , and could be detected under electrodes Fz, Cz and Pz. Significant differences were found in N400 latencies and amplitudes between matching and nonmatching ending-words. Compared with idioms with matching ending-words, N400 latencies were prolonged and amplitudes increased in nonmatching cases. The observed changes in N400 latencies and amplitudes were related to stimulus types, and the longest latency and largest amplitude were e-licited by ending-words with different pronunciation, form and meaning. No gender difference in N400 latency or amplitude was observed. Conclusions Compared with Western phonetic words, Chinese ideographic words are more flexible stimuli for N400 research, offering 3 dimensions for change: pronunciation, form and meaning. The N400 features elicited by matching and nonmatching ending words in Chinese idioms are mainly determined by the meaning of the word.

Objective To explore the features and neural generators of the events related potentials ( ERP) component N400, elicited by congruent and incongruent ending sentences, in first episode schizophrenia patients. Methods N400 was elicited by 76 congruent (31) or incongruent (45) ending Chinese sentences paradigm, and recorded by WJ-1 ERP instruments in 56 first episode schizophrenia. The neural generators of N400 different wave in 105 -615 ms time windows were analyzed by Brain Electrical Activity Mapping software. Results① The N400 latencies were significantly longer and amplitudes significantly higher in incongruent conditions than in congruent conditions in first episode schizophrenia (P < 0.05 or P <0.01).② N400 elicited by Chinese sentences distributed on frontal, parietal, occipital and temporal regions, and had a clear waveform. ③ The main brain areas activated by N400 were frontal areas in 345 -405 ms time windows, and central areas in 420 - 570 ms time windows. Conclusion N400 elicited by Chinese sentences are multi-generated in first episode schizophrenia, especially in frontal area.

BACKGROUNDNicotine may improve schizophrenia patient's cognitive deficit symptoms. This study was to explore the chronic effects of smoking on prepulse inhibition of the startle reflex (PPI) and P50 in the patients with first-episode schizophrenia (FES).

METHODSThe event-related potentials (ERP) recording and analysis instrument made by Brain Products, Germany, was used to detect PPI and P50 in 49 male FES patients (FES group, n = 21 for smokers and n = 28 for non-smokers) and 43 normal male controls (control group, n = 19 for smokers and n = 24 for non-smokers).

RESULTSCompared with normal controls, the FES group had prolonged PPI latency when elicited by single stronger stimulus (P < 0.05); the FES group had prolonged PPI latency and increased PPI amplitude (P < 0.05, 0.01) when elicited by weak and strong stimuli. The FES group had lower PPI inhibition rate than normal controls (P < 0.05). Compared with normal controls, the FES group had increased P50-S2 amplitude and increased amplitude ratio S2/S1 (both P <0.05). In the control group, the smokers had a tendency of increase in P50-S2 amplitude (P > 0.05) and shorter P50-S2 latency (P < 0.05) than the non-smokers. The smokers had higher PPI amplitude than the non-smokers (P < 0.05). In the FES group, the smokers had higher P50-S1 amplitude, shorter P50-S2 latency, and higher amplitude ratio S2/S1 than the non-smokers (P < 0.05, 0.01). The smokers had higher PPI amplitude than the non-smokers (P < 0.05).

CONCLUSIONSThere is obvious PPI and P50 deficits in schizophrenic patients. However, these deficits are relatively preserved in the smokers compared with the non-smokers, which suggests that long-term smoking might partially improve the sensory gating in schizophrenic patients. Whether this conclusion can be deduced to female patients requires further follow-ups.

Adult ; Case-Control Studies ; Evoked Potentials ; drug effects ; physiology ; Humans ; Male ; Reflex, Startle ; physiology ; Schizophrenia ; physiopathology ; Smoking ; adverse effects ; Young Adult