认知与发展心理学研究室知识库

言语异常是精神分裂症谱系的一个突出特点，研究者推测他们的语义加工过程可能出现异常。语义加工的两阶段模型将语义加工分成早期自动化的语义激活和晚期对于情境的加工两个相对独立的阶段。根据该模型人们对于分裂症患者的语义加工缺损做出了两点假设:第一病人早期自动扩散的语义激活过程存在过度激活的状况;第二病人对于情境的加工存在缺损。但是目前的发现并不一致。

相对于行为学研究而言，事件相关电位(ERP )能够更好地靶向语义加工过程。目前使用ERP技术探讨精神分裂症病人的研究在数量上已经不少，能够满足开展元分析的要求。因此在研究一中我们使用一项元分析技术来探讨病人语义加工过程的特点。我们考察了四个N400相关指标，即差异波潜伏期、差异波波幅、一致(相关)条件的波幅、不一致(无关)条件的波幅。结果发现精神分裂症病人两个语义加工过程均出现缺损。对于早期自动扩散的语义激活过程而言，病人的N400差异波波幅明显变小，但是这种变化既不能用一致(相关)条件，也不能用不一致(无关)条件的波幅变化来简单解释。对于晚期的情境加工，我们发现病人N400差异波潜伏期更长，波幅更小，而且这种波幅的变化可以由病人中对一致(相关)条件下产生的更大的N400波幅来解释。基于这种情况，我们认为早期自动扩散的语义激活存在缺损，但是这种缺损不是简单地过度激活或者激活不足。具有不同症状的病人可能有不同的缺损。此外，病人对于情境的加工速度更慢，效能更低，主要表现为不能基于之前的情境产生合理的期待，并根据情境进行意义整合。

目前探讨具有分裂型人格特质健康个体语义加工过程特点的文献并不多。基于此，在研究二中我们设计了一个内隐的语义任务和一个外显的语义任务来分别探讨分裂性人格特质的早期自动扩散的激活过程和晚期对情境的加工。初步的结果表明在内隐的语义任务中具有和不具有分裂性人格特质个体没有出现区别。这表明具有分裂型人格特质健康个体早期自动扩散的语义激活过程是正常的。两组被试的区别出现在外显的语义任务上。虽然他们在行为学启动效应上没有区别，但是在BRP启动效应上两组被试出现了现在的区别—具有分裂型人格特质个体出现和比健康个体更大的差异波，而且这种更大的差异波是相关目标词引起的更小的N400导致的。我们据此推测他们可能使用补偿策略来进行情境加工。

Abnormal speech pattern is a hallmark of schizophrenia. Impaired semantic processing has been suggested to be partly responsible for this abnormality. Theoretically semantic processing could be separated into early automatic semantic activation and late contextualization. It has been postulated that the patients' early stage of semantic processing was in a state of over-activation, and that their late contextualization was also impaired. However, findings from different groups are quite inconsistent.

Event-related potential (ERP), with its high temporal resolution at the millisecond level, is useful to investigate the nature of semantic deficits in schizophrenia. Based on the two-stage semantic processing theory, the accumulation of ERP data now enable us to carry out a meta-analysis between schizophrenia and normal control to delineate the nature of semantic processing deficit in patients with schizophrenia. Four effect sizes were computed to examine the pattern of semantic processing impairments in patients with schizophrenia for each of the components: N400 peak latency, N400 effect (the difference in the N400 amplitudes between congruent/related and incongruent/unrelated conditions), N400 amplitudes for congruent/related conditions and N400 amplitudes for incongruent/unrelated conditions. Twenty-one studies met the inclusion criteria were searched out for meta-analysis procedure. Comprehensive Meta-Analysis software package was used to compute pooled effect sizes and homogeneity. Studies favoring early automatic activation produced a significant effect size of -0.41 for N400 effect. Studies favoring late contextualization generated a significant effect size of -0.36 for the N400 effect, a significant effect size of -0.52 for N400 for congruent/related target words, and a significant effect size of 0.82 for the N400 peak latency. These findings suggest the automatic spread activation process in patients with schizophrenia was very similar for closely related concepts and weakly or remotely related concepts, while late contextualization may be associated with impairments in processing semantically congruent context accompanied by slow processing speed. So far there were few studies investigating the semantic processing features in individuals with schizotypal personality trait. We therefore conducted two ERP experiments to address their semantic processing features, with an implicit semantic task for the early stage of automatic spreading activation and an explicit task for the late contextualization. The performance of 10 individual with schizotypal personality trait was compared to 10 individuals without schizotypal personality trait. There was no between-group difference in the implicit semantic task, which suggests normal automatic spreading activation in individuals with schizotypal personality trait.

The two groups did not have difference in the behavioral date in the explicit task. However, individuals with schizotypal personality trait had larger N400 effect than individual without schizotypal personality trait. It means that they might use kind of compensation strategy for late contextualization.