脑激活定律

用物理学的观点在系统水平上讨论脑内功能子系统的脑区激活及相互作用。引入一些参量描述脑功能特性 ,并且根据现有实验事实提出脑激活的四条定律。     

听障大学生汉语阅读中的绕口令效应：口语经验和阅读能力的影响

听障者阅读时是否激活语音信息是听障者阅读研究领域的热点问题之一。本研究使用眼动技术,采用绕口令材料,考察口语经验和阅读能力对听障大学生汉语阅读中语音激活的影响。结果发现,口语经验较多且阅读能力较高(OHRH)的听障大学生的绕口令效应大于口语经验较少但阅读能力较高(OLRH)的听障大学生,OLRH组的绕口令效应大于口语经验较少且阅读能力较低(OLRL)的听障大学生。局部指标分析发现OHRH和OLRH组在早期和晚期指标上均存在绕口令效应,OLRL组只在晚期指标上才出现绕口令效应。结果表明,口语经验和阅读能力影响听障大学生汉语阅读中的语音激活。     

Spoken-word processing in aphasia: effects of item overlap and item repetition

Two studies were carried out to investigate the effects of presentation of primes showing partial (word-initial) or full overlap on processing of spoken target words. The first study investigated whether time compression would interfere with lexical processing so as to elicit aphasic-like performance in non-brain-damaged subjects. The second study was designed to compare effects of item overlap and item repetition in aphasic patients of different diagnostic types. Time compression did not interfere with lexical deactivation for the non-brain-damaged subjects. Furthermore, all aphasic patients showed immediate inhibition of co-activated candidates. These combined results show that deactivation is a fast process. Repetition effects, however, seem to arise only at the longer term in aphasic patients. Importantly, poor performance on diagnostic verbal STM tasks was shown to be related to lexical decision performance in both overlap and repetition conditions, which suggests a common underlying deficit.     

Impact of negative affectively charged stimuli and response style on cognitive-control-related neural activation: An ERP study

The canonical AX-CPT task measures two forms of cognitive control: sustained goal-oriented control (“proactive” control) and transient changes in cognitive control following unexpected events (“reactive” control). We modified this task by adding negative and neutral International Affective Picture System (IAPS) pictures to assess the effects of negative emotion on these two forms of cognitive control. Proactive and reactive control styles were assessed based on measures of behavior and electrophysiology, including the N2 event-related potential component and source space activation (Low Resolution Tomography [LORETA]). We found slower reaction-times and greater DLPFC activation for negative relative to neutral stimuli. Additionally, we found that a proactive style of responding was related to less prefrontal activation (interpreted to reflect increased efficiency of processing) during actively maintained previously cued information and that a reactive style of responding was related to less prefrontal activation (interpreted to reflect increased efficiency of processing) during just-in-time environmentally triggered information. This pattern of results was evident in relatively neutral contexts, but in the face of negative emotion, these associations were not found, suggesting potential response style-by-emotion interaction effects on prefrontal neural activation.     

激活水平和呈现方式对错误记忆的影响

随机抽取80名大学生参与实验,采用DRM(Deese-Roediger-Mcdermott)范式,探讨了激活水平和呈现方式对错误记忆的影响。结果发现:(1)在随机呈现条件下,关键诱饵的错误再认率显著低于分组呈现条件,但学过项目的正确再认率在两种条件下无差异。(2)在高激活水平条件下,学过项目的正确再认率明显低于低激活水平条件,但关键诱饵的错误再认率在两种激活条件下的差异不够明显。这表明,呈现方式对关键诱饵的错误再认率有显著影响,而激活水平的影响则不显著。由此可知,人们的记忆可以在没有任何外界信息干扰的情况下因内在联想过程而自发地发生改变。     

Influence of prolonged wearing of unstable shoes on upright standing postural control

ObjectiveTo study the influence of prolonged wearing of unstable shoes on standing postural control in prolonged standing workers.MethodsThe participants were divided into two groups: one wore unstable shoes while the other wore conventional shoes for 8 weeks. Stabilometry parameters related to centre of pressure (CoP), rambling (RM) and trembling (TR) as well as the total agonist/antagonist muscle activity, antagonist co-activation and reciprocal activation were evaluated during upright standing, before and after the 8 weeks period. In both moments, the subjects were evaluated wearing the unstable shoes and in barefoot.ResultsThe unstable shoe condition presented increased CoP displacement related variables and decreased co-activation command compared to barefoot before and after the intervention. The prolonged wearing of unstable shoes led to: (1) reduction of medial–lateral CoP root mean square and area; (2) decreased anteroposterior RM displacement; (3) increased anteroposterior RM mean velocity and mediolateral RM displacement; (4) decreased anteroposterior TR RMS; and (5) increased thigh antagonist co-activation in the unstable shoe condition.ConclusionThe unstable shoe condition is associated to a higher destabilising effect that leads to a selection of more efficient and accurate postural commands compared to barefoot. Prolonged wearing of unstable shoes provides increased effectiveness and performance of the postural control system, while wearing of unstable shoes in upright standing, that are reflected by changes in CoP related variables and by a reorganisation of postural control commands.     

自闭症谱系障碍的生物基础

自闭症谱系障碍是一组发病于生命早期, 由一系列生理、心理因素引起的神经发育障碍。遗传、脑神经结构、营养素等是自闭症谱系障碍的生物基础的重要来源。个体在孕育早期形成的大脑和机体异常可能是导致自闭症谱系障碍的关键。这种异常在出生后的发育中具体作用于神经活动、脑发育、免疫系统等生理途径。研究者们今后可以尝试横跨不同自闭症谱系障碍亚型、年龄和发育阶段, 开展横向与纵向相结合的大范围研究, 以进一步明确自闭症谱系障碍的生物基础。     

语义启动模型以及启动范围

启动效应一般分为两种——知觉启动和语义启动(概念启动)。语义启动的范式逐渐成为研究语义知识在大脑中是如何存储的主要研究手段。该文针对语义启动发生的3种机制:激活扩散模型,复合线索模型和分布式记忆模型进行了简要的评述,并且重点介绍了分布式记忆模型。同时对启动效应可以激活语义知识的范围作了一个简要的概括。     

图形和汉字视觉认知任务中的部分线索效应

给被试呈现一幅图的不完整信息作为线索会干扰被试对图形的辨认,这是一种部分线索效应。实验一的任务是对模糊图形的辨认,在轮廓相似组图形中,部分线索的干扰作用随呈现模糊级次数的增加而更加显著,但在轮廓非相似组图形中,模糊级呈现次数为２次和３次的情况下,也表现出了显著的部分线索效应。实验二在不完整汉字识别任务中进一步考察了部分线索效应,在事先学习的条件下,形状相似字组汉字的辨认表现出了显著的部分线索效应,而意义相似字组和随机字组汉字的辨认表现出了部分线索的促进作用。在事先不学习的条件下,随机字组和形状相似字组汉字的辨认表现出了显著的部分线索效应,而意义相似字组汉字的辨认没有表现出显著的部分线索效应。本研究用激活的观点对这些结果做出了合理的解释。     

自我损耗促进冒险行为

基于自我控制资源模型,本研究探讨了自我损耗对冒险行为的影响以及生理能量补充在其中的缓解作用。实验1和实验2分别通过“Stroop”和“非利手写作”任务操纵被试的自我损耗,两个实验均用气球模拟风险决策任务考察被试的冒险行为,并且通过摄入含有或不含有葡萄糖的柠檬水来操纵生理能量水平。结果发现,在排除无关变量后,高损耗者比低损耗者尽可能多地对气球进行充气以寻求奖赏(实验1和实验2),但饮用含葡萄糖的柠檬水能够有效降低这种反应(实验2)。该研究证实了自我损耗促进冒险行为,补充生理能量能有效缓解该效应。