An event-related potential study of predictive and integrative semantic context processing in subjects with schizotypal traits

N400 Peculiarities During Intentional Inferences Production in Subjects With Schizotypal Traits

Abstract. A deficit in context processing may underlie theory of mind (ToM) difficulties in schizophrenia, although few studies to date have explored the impact of contextual processing on ToM performances within the same task. We used electroencephalography to investigate the production of intentional inferences from highly versus weakly structured sentences in healthy participants with schizotypal traits. Thirty-four participants were divided into two groups according to their scores on the Schizotypal Personality Questionnaire (SPQ). The participants listened to stories that required a degree of understanding in order to produce an inference about the main character’s intention. Each story was followed by a target word that could either be highly predictable (HP), weakly predictable (WP), or incompatible with the context. The results indicate that the N400 component for WP targets was stronger in the high-SPQ group. This increase correlated with the negative dimension of schizotypy. This may reflect difficulties with generating intentional inferences when the context is insufficiently structured for high schizotypy participants.

Neural correlates of contributions of interpreting training to second language semantic integration

How interpreting training may enhance semantic integration in general language processing (instead of language processing during interpreting) was not clear, and its neural correlates remained unexplored. Two groups of university students with different amounts of interpreting training experience (more-IE and less-IE) performed a second language (L2) reading task, in which the target sentence ended with three types of lateralized words: expected words, words of related semantic violation (related violation), and words of unrelated semantic violation (unrelated violation). N400 responses elicited by the final words were used to index semantic integration. Two major findings suggested potential contributions of interpreting training to L2 semantic integration. First, the more-IE group exhibited smaller N400 amplitudes than the less-IE group for expected words, and no group differences were obtained for the two violations. Second, N400 amplitudes for related violations were generally smaller than those for unrelated violations in the right visual field, and this difference was more fully captured (more broadly distributed over the scalp) in the more-IE group than in the less-IE group. Therefore, smaller N400 amplitudes for expected words but not for violations, and broader scalp distribution of the differences between related and unrelated violations constitute the neural correlates for the potential contributions of interpreting training to general L2 semantic integration. The results also suggest possible connections between different types of language experience.

Lexical and sub-lexical reading skills and their correlation to clinical symptoms in young Chinese patients with schizophrenia

Patients with schizophrenia often experience severe reading deficits such as oral reading and reading comprehension deficits. However, it is not known whether different types of lexical or sub-lexical components in reading are also impaired. In order to address this issue, the present study had 22 young Chinese patients with schizophrenia and 22 young Chinese normal controls undergo a battery of reading tests, which specifically measures lexical and sub-lexical components of reading in Chinese. The schizophrenic group further underwent Brief Psychiatric Rating Scale (BPRS) in order to ascertain the severity of patients' clinical symptoms. The results showed that compared to the controls, (1) the schizophrenic patients performed significantly poorly in orthographic processing, orthography-phonology mapping, and orthography-semantic mapping tests and further that (2) their performances in orthographic processing, and orthography-semantic mapping skill tests negatively correlated with the BPRS score. Note however that their ability to access their mental lexicon was intact. There is thus a clear need for studies with a larger sample-size and neurobiological measures which would lead to our better understanding of the behavioral as well as the neural relationships between schizophrenic patients, and their reading processing impairments, thus developing effective reading intervention programs for the schizophrenic patients.

Event-related brain potential study of expectancy and semantic matching in schizotypy

Priming studies have revealed semantic processing abnormalities in subjects that display high schizotypal traits. The objective of the present study was to further elucidate the contribution of predictive (expectancy) and integrative (semantic matching) context processing to the semantic deficit described in schizotypy. Thirty-six participants were assigned into high or low schizotypy groups according to their score on the Schizotypal Personality Questionnaire (SPQ), and event-related brain potentials were recorded while these individuals performed semantic judgments based on asymmetrically associated word pairs. Viewed in one direction (forward), the target was highly predictable from the prime, whereas in the backward direction, the prime-to-target association was weak. It was assumed that the forward condition would be dependent on expectancy generation, while the backward condition would rely on semantic matching. In the low-SPQ group, forward and backward related words evoked a reduced (less negative) N400 amplitude compared to unrelated words, resulting in a significant forward and backward N400 priming effect, respectively. By contrast, only forward related words were facilitated in the high-SPQ group, resulting in significant forward priming and a lack of backward priming. Furthermore, the N400 amplitude for forward related words was less negative within the high-SPQ group in comparison to the low-SPQ group, which indicated easier semantic access to predictable words for high-SPQ individuals. Therefore, schizotypy may be associated with an imbalance in the use of predictive and integrative context processing strategies, namely preserved, if not over allocated, expectancy generation along with altered integration of unpredictable words due to semantic matching deficit.

Spatial analysis of schizotypal personality traits in Chinese male youths: evidence from a GIS-based analysis of Sichuan

Background

Schizotypal personality traits are associated with schizophrenia spectrum disorders, stating that schizotypal traits may represent a “prodrome” or other developmental precursor of schizophrenia. Genetic and environmental factors both play importanxt roles in the development of schizotypal traits. Different levels of schizotypal traits across regions may be indicative of similar differences in the incidence of schizophrenia.

Aim

The present study identifying where in a given region, schizotypal personality traits are more or less level of schizotypal personality scores in Chinese male youth of Sichuan province. Not only for research purposes but also for the evaluation of new draft and allocation policy initiatives intended to aid recruitment of mental health employees.

Methods

Data from the Psychological Selection Systems for Chinese Recruits, a mental health screening system used in China, collected in 2011 (67,558 copies) were used to map spatial distribution of schizotypal personality traits using geostatistics and geographic information system (GIS) techniques. Correlation analyses were conducted to explore the effects of years of education and illiterate rate on schizotypal personality traits.

Results

Maps for three schizotypal personality clinical scales (dissociative, Dit; neurotic, Net and sensitive, Set) showed similar geographical trends. The highest T scores were distributed mainly in the eastern and northern counties of Sichuan, with scores decreasing successively from east to west, with the eastern counties generally showing higher scores. Correlation analysis showed that t-scores of Set were negatively correlated with years of education, whereas t-scores of Net were negatively correlated with illiteracy rate.

Conclusions

Schizotypal personality traits in male youth showed specific geographical trends in Sichuan province, providing some evidence that kriging based on GIS can be used to geographically localize genetic and environmental factors associated with schizotypal personality traits. This approach could be used to help allocate public health resources to specific areas and could also have personnel selection applications.