Department of Psychiatry, College of Medicine, Konyang University, Daejeon, South Korea.
Prog Neuropsychopharmacol Biol Psychiatry. 2012 Aug 7;38(2):194-200. doi: 10.1016/j.pnpbp.2012.03.009. Epub 2012 Mar 29.
Various formal thought disorders are presented as symptoms by manic patients including pressure of speech, flight of ideas, and more complex speech with strong emotional components. N400 is the event-related potential, in which amplitude is suggested to be a general index of efforts to retrieve stored semantic context, which depends on the stored representation itself and the retrieval cue stimuli. The present study examines N400 components induced by a word-matching task in manic patients, and compare these responses to those induced by the task in schizophrenia and healthy controls.
Twenty manic patients, twenty schizophrenic patients, and twenty healthy controls performed the word-matching task, in which they were presented with 120 (60 congruent and 60 incongruent) word pairs, they were instructed to discriminate whether each word pair was congruent or incongruent. During the task, we recorded the electroencephalogram.
Reaction time analysis revealed a main effect for priming, in which reaction times were longer in response to incongruent words than to congruent words in all three participant groups (F=43.1, p<0.001) with no group effects (F=2.3, p=0.11). N400 analysis showed the main effect for priming (F=30.2, p<0.001), for group (F=5.0, p=0.01), and the interaction of priming×group (F=4.6, p=0.02). Post-hoc analysis of this interaction revealed larger N400 amplitudes to congruent words in manic patients (F=4.0, p=0.02) and smaller N400 to incongruent words in schizophrenic patients than in other groups (F=6.1, p=0.004). No correlations were found between N400 and symptom severity within patient groups.
These findings suggest that priming effects of contextually related word pairs are decreased in patients with bipolar mania, whereas priming N400 responses of contextually unrelated word pairs are increased in schizophrenia. This may be the neurophysiological evidence of abnormal automatic semantic processing in patients with bipolar mania, and it also reflects a qualitative difference in thought and speech disorders between bipolar manic and schizophrenia.
各种形式的思维障碍在躁狂患者中表现为言语紧迫感、思维奔逸等症状，以及更复杂的具有强烈情感成分的言语。N400 是事件相关电位，其幅度被认为是检索存储语义上下文的一般指标，这取决于存储的表示本身和检索线索刺激。本研究通过对躁狂患者进行词匹配任务来检查 N400 成分，并将这些反应与精神分裂症和健康对照组的任务诱导的反应进行比较。
20 名躁狂患者、20 名精神分裂症患者和 20 名健康对照组完成了词匹配任务，他们被呈现 120 对（60 对一致和 60 对不一致）词对，他们被指示判断每对词是否一致。在任务过程中，我们记录了脑电图。
反应时间分析显示，启动有主效应，在所有三组参与者中，对不一致词的反应时间长于对一致词（F=43.1，p<0.001），没有组效应（F=2.3，p=0.11）。N400 分析显示启动的主效应（F=30.2，p<0.001）、组的主效应（F=5.0，p=0.01）和启动×组的交互作用（F=4.6，p=0.02）。对这种相互作用的事后分析显示，躁狂患者对一致词的 N400 振幅更大（F=4.0，p=0.02），而精神分裂症患者对不一致词的 N400 振幅比其他组更小（F=6.1，p=0.004）。在患者组内，未发现 N400 与症状严重程度之间存在相关性。
这些发现表明，双相躁狂症患者语境相关词对的启动效应降低，而精神分裂症患者语境不相关词对的启动 N400 反应增加。这可能是双相躁狂症患者异常自动语义加工的神经生理证据，也反映了双相躁狂症和精神分裂症之间思维和言语障碍的质的差异。
