Irrelevant sensory stimuli interfere with working memory storage: Evidence from a computational model of prefrontal neurons

The encoding of irrelevant stimuli into the memory store has previously been suggested as a mechanism of interference in working memory (e.g., Lange & Oberauer, Memory, 13, 333–339, 2005; Nairne, Memory & Cognition, 18, 251–269, 1990). Recently, Bancroft and Servos (Experimental Brain Research, 208, 529–532, 2011) used a tactile working memory task to provide experimental evidence that irrelevant stimuli were, in fact, encoded into working memory. In the present study, we replicated Bancroft and Servos’s experimental findings using a biologically based computational model of prefrontal neurons, providing a neurocomputational model of overwriting in working memory. Furthermore, our modeling results show that inhibition acts to protect the contents of working memory, and they suggest a need for further experimental research into the capacity of vibrotactile working memory.     

伤害回避的脑机制及其生物基础

伤害回避是指个体对厌恶刺激信号做出强烈的反应,并学会被动地回避惩罚的一种倾向,这一倾向使得个体反复思考未来的结局,并谨慎小心地对待不确定情景中的事件,进而更有可能诱发情感障碍。伤害回避涉及的神经网络包括三个子网络,即额顶叶-前扣带皮层的连接、皮层-杏仁核的连接和白质通道的结构性连接,这三个子网络分别与羞怯感-易疲劳性、预期担心以及不确定环境中的害怕情绪有关。而其生物基础则包括单一基因多态性和基因多态间的交互作用。今后的研究应该集中在深化伤害回避神经网络与生物基础间的联合机制、研究三种及以上基因多态间的交互作用、考察其他因素对基因效应的调节作用、注重伤害回避四种亚型相关神经网络之间的连接、探讨5-HT4等其他几种5-羟色胺受体多态性与伤害回避的关系以及分析伤害回避内部机制在抗抑郁治疗中的作用等方面。     

Regularity of unit length boosts statistical learning in verbal and nonverbal artificial languages

Humans have remarkable statistical learning abilities for verbal speech-like materials and for nonverbal music-like materials. Statistical learning has been shown with artificial languages (AL) that consist of the concatenation of nonsense word-like units into a continuous stream. These ALs contain no cues to unit boundaries other than the transitional probabilities between events, which are high within a unit and low between units. Most AL studies have used units of regular lengths. In the present study, the ALs were based on the same statistical structures but differed in unit length regularity (i.e., whether they were made out of units of regular vs. irregular lengths) and in materials (i.e., syllables vs. musical timbres), to allow us to investigate the influence of unit length regularity on domain-general statistical learning. In addition to better performance for verbal than for nonverbal materials, the findings revealed an effect of unit length regularity, with better performance for languages with regular- (vs. irregular-) length units. This unit length regularity effect suggests the influence of dynamic attentional processes (as proposed by the dynamic attending theory; Large & Jones (Psychological Review 106: 119–159, 1999)) on domain-general statistical learning.     

Towards a distributed account of conceptual knowledge

How is conceptual knowledge organized and represented? Are domains (such as living things) and categories (such as tools, fruit) represented explicitly or can domain and category structure emerge out of a distributed system? Taken at face value, evidence from brain-damaged patients and neuroimaging studies suggests that conceptual knowledge is explicitly structured in independent content-based stores. However, recent analyses of the fine-grained details of semantic impairments, combined with research using connectionist modelling, suggest a different picture - one in which concepts are represented as patterns of activation over multiple semantic properties within a unitary distributed system. Within this context, category-specific deficits emerge as a result of differences in the structure and content of concepts rather than from explicit divisions of conceptual knowledge in separate stores.     

提取练习在记忆保持与迁移中的优势效应：基于认知负荷理论的解释

提取练习比建构概念图更有利于记忆保持和迁移的研究结果尚存在争议。依据认知负荷的3个成分,设计两个实验探究前期知识水平与策略复杂性对以上两种学习策略有效性的影响。结果表明：(1)前期知识水平的主效应不显著,但是与学习策略之间存在交互作用：在提取练习策略条件下,高前期知识水平的被试与低前期知识水平的被试在记忆保持和迁移上的正确率没有显著差异,但是在建构概念图策略条件下,高前期知识水平的被试在记忆保持和迁移上的正确率显著地高于低前期知识水平的被试;(2)当降低概念图的难度后,被试使用建构部分概念图策略产生的认知负荷与使用提取练习策略相比显著降低,并且其在学习阶段学习到的知识量显著地高于使用提取练习策略的结果,但是在最终测试上,其记忆保持与迁移的正确率与使用提取练习策略并没有显著差异,策略的复杂性增加了学习者的额外负荷,但是对策略有效性的发挥却不具有决定性影响。以上结果说明提取练习策略之所以比建构概念图策略更具优势,不是因为其策略本身更易掌握,而是因为其与建构概念图策略相比不受学习者前期知识水平的影响。这意味着认知负荷理论可以很好地解释提取练习在记忆保持与迁移中产生优势效应的内部机制,并进一步证实提取练习与精细编码不同,具有独特的加工机制。     

支持型领导行为在工作压力模型中的作用机制研究

本研究调查了 1 3个企业共 2 1 8位员工 ,探讨了支持型领导行为在角色冲突、人际冲突、缺乏成就与发展 (压力源 )和工作满意感、工作焦虑 (压力反应 )之间的作用机制。研究发现 :(1 )支持型领导行为对工作满意感和工作焦虑有主效应 ,但是由于逆向缓冲的存在 ,支持型领导行为的主效应并不总是对的 ,我们必须在更大的范围中考虑领导行为的效应 ;(2 )缓冲效应的六个假设只有一个被证明 ,但是方向相反 ,即支持型领导行为加剧了由人际冲突造成的工作不满意感 ;(3)两个中介模型的部分关系被证明 ,但是我们很难确定是支持型领导行为的弱化效应还是评价作用。为了更好地说明因果关系 ,在将来的研究中纵向研究设计被认为更为恰当。     

Latent variable assessment of outcomes in a nurse-managed intervention to increase latent tuberculosis treatment completion in homeless adults.

OBJECTIVE: To assess predictors of latent tuberculosis infection (LTBI) completion by using structural equation modeling (SEM) among homeless adults, a group at great risk for LTBI and active tuberculosis (TB). LTBI therapy is effective in stemming the progression to active TB, yet treatment adherence among homeless persons is difficult to attain. DESIGN: By using SEM, the authors assessed predictors of LTBI completion among a sample of 494 homeless adults in Los Angeles, CA, who received either a nurse case-managed program (NCM) or a usual care program. MAIN OUTCOME MEASURES: Latent variables were created with the baseline variables of site type, age, intervention status, dissatisfaction with health care, depression, TB risk assessment, alcohol use, heroin or cocaine use, and TB knowledge. Outcome variables included many of the same baseline variables as well as treatment completion. RESULTS: LTBI treatment completion (100% adherence) was significantly and positively associated with participation in NCM, older age, and less heroin or cocaine use. NCM also predicted greater TB knowledge, greater ease of treatment, and more satisfaction with treatment (NCM completion rate = 64%, control rate = 42%). CONCLUSION: The culturally competent NCM program, combined with active tracking and incentives, was successful in a difficult-to-treat and highly transient population.