Analysis of Semantic and Working Memory in Schizophrenia by Event-Related Potentials

我们已经检查了精神分裂症的病理生理学观察领域的认知功能，如知觉，思维（语言），和记忆，通过使用一种新的实验范式，在视觉事件相关的脑电位研究，并发现异常NA和N400电位在缓解患者，这反映了模式识别和语义处理，分别。我们的前瞻性随访研究证实，NA异常是精神病复发的脆弱性标志，其特征是华丽的幻觉和妄想。本研究旨在探讨N400异常在精神分裂症中的发病机制及其临床意义，特别是参考思维障碍指数（TDI）（约翰斯顿和Holzman 1979）评估的精神分裂症思维障碍。N400的重复激发与TDI总分无关。然后根据TDI分数将患者分为低TDI和高TDI两组，发现重复启动与思维障碍仅在高TDI患者中存在显著相关。这些结果表明，异常的N400可能与NA异常无关，异常的N400可能不是由于N400产生机制的缺陷（语义处理），但N400调节机制不足精神分裂症的部分思维障碍可能是由工作记忆的缺陷引起的。精神病症状（幻觉和妄想）、形式思维障碍和缺陷症状。除了这种临床异质性精神分裂症，我们的数据表明，异质性的病理生理学水平，因为异常NA作为精神病症状的脆弱性是独立的异常N400作为和指数的思维障碍。

We have examined a pathophysiology of schizophrenia observed in the domains of cognitive functions such as perception, thinking (language), and memory by using a new experimental paradigm in visual event-related brain potential study, and found aberrant NA and N400 potentials in remitted patients, which reflect a pattern-recognition and a semantic processing, respectively. Our prospective follow-up study confirmed the NA abnormality to be a vulnerability marker of psychotic relapse characterized by florid hallucination and delusion. This study was designed to investigate a pathogenesis of N400 abnormality in schizophrenia and its clinical significance with a special reference to schizophrenic thought disturbance assessed by Thought Disorder Index (TDI) (Johnston and Holzman 1979).Parameters of N400 did not correlate to those of NA, and N400 abnormality was clearly observed in repetition priming rather than semantic processing of Japanese words. Repetition priming f N400 did not correlate to the total TDI scores. Then we divided into low TDI and high TDI patients according to TDI scores, and found a robust correlation between repetition priming and thought disturbance only in high TDI patients. These results suggest that aberrant N400 may be independent of NA abnormality, that aberrant N400 may not be due to a deficit in N400 generation mechanism (semantic processing) but a deficit in N400 regulation mechanism (memory processing), and that a part of schizophrenic thought disturbance may be caused by a deficit in working memory.Recent studies have reported that schizophrenic symptoms consist f three dimensions ; psychotic symptoms (hallucination and delusion), formal thought disorder, and deficit symptoms. In addition to such a clinical heterogeneity in schizophrenia, our data suggest a heterogeneity in a level of pathophysiology because aberrant NA as a vulnerability of psychotic symptoms was independent of aberrant N400 as and index of thought disturbance.