汉语句子-图片信息整合的眼动测量

采用眼球追踪-分析法考察了“句子-图片”验证范式下句图信息整合过程中句式和语义关系类型的作用。实验结果表明：（1）汉语句子-图片信息整合过程中,句图继时呈现没有消除语义失配效应,注视次数、总注视时间显著增加,瞳孔直径扩大。语义失配会显著干扰句法难度低的句式的句图信息整合。（2）句式影响句子-图片信息的整合过程,注视次数、总注视时间、瞳孔直径随句法难度增加而增加。（3）汉语句图信息整合过程中,语义失配效应受句式影响,表现出任务的特异性,这说明成分比较模型不具有一般性     

语义知识神经表征的fMRI研究：通道特异性或类别特异性？

在同一实验中同时考虑类别与通道二个因素,并采用典型的语义提取任务应用功能磁共振成像技术探讨了语义知识的神经基础,结果发现不同类型的语义知识的脑激活模式（含左梭形回的激活）无论在范围还是强度上存在很大的相似性;而且,在严格的统计阈值下,不存在通道或是类别特异性激活的脑区。结果提示语义知识的神经表征分布于整个大脑皮层;在提取物体语义知识时都会同时激活该物体的视觉表象。另外,研究观察到的语义提取过程中BA9区的激活进一步证实并扩展了关于“汉语和表音文字在皮层组织上存在重要差异的观点”。     

新颖语义联结在顿悟促进记忆效果中的作用

采用成语谜题选择任务, 通过学习-测验范式探究顿悟促进记忆的认知神经机制。实验1采用行为实验, 验证成语谜题选择范式在探究顿悟促进记忆中的有效性, 结果显示, 相比于寻常联结条件, 新颖联结条件下被试在学习阶段具有更高的顿悟感得分, 在测试阶段具有更高的正确率, 范式的有效性得以验证。实验2采用fMRI技术探究顿悟促进记忆的关键脑区。结果显示, 相比于失败记忆新颖联结条件, 成功记忆新颖联结条件更强地激活了顿悟过程相关脑区, 包括海马、杏仁核、额中回、颞上回和颞中回。这说明在学习阶段的顿悟问题解决过程中, 对信息的深加工与积极情绪促进了随后的记忆; 对其进一步分析发现, 相比于寻常联结记忆, 新颖联结对记忆的促进效应主要与右侧海马激活有关, 它可能反映了在顿悟问题解决中新颖联结形成过程建立了情节记忆以及新颖且有价值的语义联结。研究结果表明新颖语义联结形成在顿悟促进记忆中发挥了重要作用。     

语义空间的研究方法

对于语义空间的研究一直是认知心理学研究的一个热点。由于对词汇语义系统的不同观点,科学家们试图从不同的角度采用不同的方法来进行研究。目前,有代表性的语义空间研究方法主要有两种:潜在语义分析(LSA)和语言的多维空间类比(HAL)。潜在语义分析是指利用奇异值分解的方法来探索文章中潜在的语义关系的方法;语言的多维空间类比则是利用多维量表(MDS)的方法来提取语义信息。     

任务需求对语义水平负相容效应的影响

结合掩蔽启动范式和Go-Nogo范式, 证明了语义水平负相容效应的存在, 考察了任务需求对语义水平负相容效应的影响。实验以汉字“左”和“右”作为掩蔽启动项, 在两个Block的Go试次中分别以双箭头和汉字为目标项, 要求被试做辨别反应, 在Nogo试次中不呈现目标项, 无需反应。行为结果发现, 只有当启动项与任务需求相关时才出现负相容效应。ERP结果发现, 只有在任务需求相关时Go任务中一致条件下的P3潜伏期更长; Nogo任务中, 相关条件下两种汉字启动项诱发的N2平均波幅差异显著, 相关和无关两种条件下P3波幅差异显著。说明语义水平负相容效应受自上而下任务需求影响, 这种影响是通过自上而下认知控制加工的调节实现的。     

DRG改革背景下负向医疗行为的成因分析及治理策略

我国按疾病诊断相关分组支付方式改革过程中出现了诸如选择性收治患者、诱导住院等负向医疗行为,运用舞弊三角理论分析其成因发现,医疗机构在改革过程中面临的压力和医生自我合理化心态是诱发负向医疗行为的客观外因和主观内因;此外,改革过程中各利益相关主体信息不对称、法律法规不健全以及监管效能低下等,也是导致负向医疗行为的重要因素。针对压力、机会及自我合理化三方面,从减轻医生逐利压力、完善监督医疗行为的信息系统和法律法规、提高内外部监督效能、培养医德、营造医风氛围等方面,为改革提供合理建议。

     

Neuropsychological differentiation of progressive aphasic disorders

The differentiation of subtypes of primary progressive aphasia (PPA) remains challenging. We aimed to identify optimum neuropsychological measures for characterizing PPA, to examine the relationship between behavioural change and subtypes of PPA and to determine whether characteristic profiles of language, working memory, and behavioural changes occur in PPA. Forty-seven patients with PPA and multi-domain Alzheimer's disease (AD) together with 19 age-matched controls underwent a large battery of working memory and language tests. We found that simple tasks of sentence ordering, narrative production, and buccofacial praxis were particularly useful in differentiating non-fluent/agrammatic variant PPA (nfvPPA) from other PPA subtypes, whereas a test of single word comprehension was useful in detecting semantic dementia (SD). No individual tests were discriminating for logopenic variant PPA (lvPPA) relative to nfvPPA. LvPPA and multidomain AD exhibited similar language profiles. A principal components analysis revealed that characteristic PPA profiles extended beyond the realms of language, in particular, the presence of apraxia in nfvPPA, behavioural changes in SD, and working memory deficits in lvPPA. These findings suggest that not all tests are equally discriminatory for PPA and highlight the importance of a test profile in differentiating PPA. These results also support the view that lvPPA is a focal form of AD and emphasize the difficulties classifying lvPPA.     

Mechanical knowledge does matter to tool use even when assessed with a non-production task: Evidence from left brain-damaged patients

In the literature on apraxia of tool use, it is now accepted that using familiar tools requires semantic and mechanical knowledge. However, mechanical knowledge is nearly always assessed with production tasks, so one may assume that mechanical knowledge and familiar tool use are associated only because of their common motor mechanisms. This notion may be challenged by demonstrating that familiar tool use depends on an alternative tool selection task assessing mechanical knowledge, where alternative uses of tools are assumed according to their physical properties but where actual use of tools is not needed. We tested 21 left brain-damaged patients and 21 matched controls with familiar tool use tasks (pantomime and single tool use), semantic tasks and an alternative tool selection task. The alternative tool selection task accounted for a large amount of variance in the single tool use task and was the best predictor among all the semantic tasks. Concerning the pantomime of tool use task, group and individual results suggested that the integrity of the semantic system and preserved mechanical knowledge are neither necessary nor sufficient to produce pantomimes. These results corroborate the idea that mechanical knowledge is essential when we use tools, even when tasks assessing mechanical knowledge do not require the production of any motor action. Our results also confirm the value of pantomime of tool use, which can be considered as a complex activity involving several cognitive abilities (e.g., communicative skills) rather than the activation of gesture engrams.     

The attribute priming effect in patients with Alzheimer's disease

Experiments with semantic priming (SP) paradigms have documented early hypopriming in patients with AD when concepts are used as primes and attribute concept features as targets, suggesting that concept attributes are vulnerable to damage very early in the disease course. The aims of this study were to confirm early priming reduction in the attribute condition in patients with AD and to determine which of several semantic indexes (such as the level of distinctiveness, correlation or feature dominance of concept features) best predicts the priming effect size in AD. We administered an SP attribute condition paradigm to 20 mildly demented patients with AD and to 10 NCs. We used concept–attribute pairs for which normative data of semantic indexes relative to both concept primes (i.e., number, type, mean level of dominance, distinctiveness and correlation of features constituting the concepts) and target features (i.e., level of feature dominance, correlation and distinctiveness) were available. Results showed that compared to NCs, the AD group obtained very reduced priming facilitation. Furthermore, the item regression analyses showed that the priming decrement in the AD group was predicted by the feature dominance of the target in the related pairs; that is, the lower the target feature dominance, the lower the priming effect elicited. These results confirmed hypopriming in the attribute condition from the very early phase of AD and support the view that attributes which are more salient for the identification of a given concept are also those most resistant to semantic memory degradation in AD pathology.     

The effects of marital status on episodic and semantic memory in healthy middle-aged and old individuals

The present study examined the influences of marital status on different episodic and semantic memory tasks. A total of 1882 adult men and women participated in a longitudinal project (Betula) on memory, health and aging. The participants were grouped into two age cohorts, 35-60 and 65-85, and studied over a period of 5 years. Episodic memory tasks concerned recognition and recall, whereas semantic memory tasks concerned knowledge and fluency. The results showed, after controlling for education, some diseases, chronological age and leisure activity as covariates, that there were significant differences between married and single individuals in episodic memory, but not in semantic memory. Married people showed significantly better memory performances than singles in both subsystems of episodic memory, that is, recall and recognition. Also, the rate of decline in episodic memory was significantly larger for singles and widowed than other groups over the 5-year time period in both age groups. The findings demonstrate that the positive relation found between marriage and health can be extended to the relation between marriage and cognitive performance. This effect might be explained by the role played by cognitive stimulation in memory and cognition.