Perforant path activation modulates the induction of long-term potentiation of the schaffer collateral--hippocampal CA1 response: theoretical and experimental analyses

In one computational model of hippocampal function, the entorhinal cortical input to CA1 is hypothesized to play a key role in the ability of CA1 to decode CA3 recodings. Here, we develop a modification of this CA1 decoder hypothesis that is applicable to several computational theories of hippocampal function, and then we electrophysiologically investigate one assumption of this new hypothesis. First, using biologically realistic estimates, we calculate that CA3-induced CA1 excitation is too high and that inhibition plausibly plays a role in this CA1 decoder model. Thus motivated, we turn to a physiological demonstration to substantiate the plausibility of the proposed mechanism. Using the rat hippocampal slice, we examine an interlaminar interaction between the distal perforant path input to hippocampal CA1 stratum moleculare and the more proximal Schaffer collateral input to stratum radiatum. Perforant path activation provides sufficient inhibition to block homosynaptic long-term potentiation elicited by a suitably strong stratum radiatum input. For this interlaminar interaction to be most effective, perforant path activation must both precede and follow Schaffer collateral activation. Perforant path-evoked inhibition in CA1 can thus serve as a viable mechanism in the learned decoder theory of hippocampal CA1.     

Differences in the micromechanical properties of dendrites and interdendritic regions in superalloys

Statistical analysis of white-light interferometry (WLI) experiments performed on Ni-based single-crystal superalloys (SX) have revealed a different height distribution between the dendritic cores (DCs) and the interdendritic regions (IRs) of the polished samples. The micromechanical property difference is largely ascribed to the uneven distribution of the alloying elements. In this context, possible reasons for this difference are discussed by comparing with different experiment results obtained by previous researchers, and a proposal forecasting the hardness ratio of IRs/DCs is put forward.     

应聘者印象管理研究述评

应聘者的印象管理行为在求职面试情境中是一种普遍现象,其目的旨在赢得面试考官的良好评价。应聘者印象管理行为包括有3类策略：获得性策略、保护性策略及非言语策略;同时,对应聘者印象管理行为的测量也要从印象管理策略的测量和印象管理风格的测量两个方面入手。另外,在整合已有文献的基础上,还从面试情境与应聘者印象管理行为、应聘者个性特质与印象管理策略使用、应聘者印象管理行为与面试结果及招聘者对应聘者印象管理识别等4个方面综述了应聘者印象管理研究的发展现状,并指出了现有研究存在的问题及未来研究的方向     

Space-based visual attention models and object selection: Constraints,problems, and possible solutions

Summary One of the functions of visual attention is the selection of object information. This seems to be in line with an influential group of attentional models that assume that attentional selection is space based. These models assume that the selection of an object in vision is realized by selection of the location of that object. Whether this relatively simple idea of space-based attention and the corresponding, more elaborated space-based models are sufficient to handle selected constraints and problems of object selection is the main issue of this article. The first step toward an answer is to describe the common computational structure of space-based attentional models. Two model classes will be distinguished: capacity-limited models (e.g., Treisman, 1988; LaBerge & Brown, 1989) and models that do not assume a capacity limitation (e. g., Van der Heijden, 1992). Next, three kinds of task and data on object selection are introduced that are especially challenging for space-based models. The first type of data refers to experiments that require selection between overlapping objects. The second type of data concerns the influence of early perceptual grouping - a strong object-defining factor- on late response competition, and the third type consists of a selection task in which a high-level (semantic) attribute defines an object and controls selection. In all three cases, problems of space-based models are analyzed and possible solutions are sketched. Finally, a brief evaluative summary is given.     

社会认同理论视野下的社会认同威胁

社会认同威胁是指,在社会比较的情况下,由于群体地位的差异,某一群体的个体在认知、情感上,对自我、所属群体身份的不承认,而产生的一种心理上的疏离感和剥夺感、自卑感。社会认同威胁的结果包括3类：脱离群体、改变群体的状态、接受消极的社会认同结果。外显“社会威胁”的测量方法以问卷调查为主。测量“社会威胁”的内隐方法则以心脏血压和平均动脉血压作为测量指标。社会认同威胁的实验研究将群体分化为内群体和外群体,操纵群体地位的差异,通过模拟社会游戏来了解群体的社会认同威胁及其生理反应。未来的研究将重点关注下述问题：对社会认同威胁概念的建构、跨文化研究及其内隐过程的分析     

咀嚼口香糖对认知及情绪的影响

本文系统地综述了近期关于咀嚼口香糖对负性情绪调节和认知功能的影响,以及咀嚼口香糖的脑机制的实验研究.这些研究发现,咀嚼口香糖对人们的负性情绪调节,注意、记忆、学习等认知功能起到了积极的促进作用,咀嚼口香糖所激活的脑区与负责运动、记忆、注意和情绪等高级功能的脑区有一定的重叠.     

Characterisation of magnesium oxide and its interface with α-Mg in Mg–Al-based alloys

Magnesium oxide (MgO) films and particles have been collected by pressurised filtration of a Mg-8.6wt%Al-0.67wt%Zn (AZ91D) alloy melt. The morphology of the oxides and their interfaces with the α-Mg phase were investigated by high-resolution transmission electron microscopy. It was found that the oxide films consisted of large numbers of sub-micrometre-sized MgO particles, and that melt shearing can effectively break up the oxide films and disperse the oxide particles. For the first time, orientation relationships (ORs) of OR I: [1?1?1]_MgO～2° from (0?0?0?1)_α-Mg and (0?1?1)_MgO?//[2?1?1?0)_α-Mg; and OR II: (1?1?1)_MgO//(1?1?0?1)_α-Mg and [0?1?1]_MgO//[1?2?1?1]_α-Mg, were observed between the MgO particles and the α-Mg matrix. The calculated Bramfitt planar disregistries were 5.5% and 2.5% for the two ORs, respectively, indicating good lattice matching between MgO and α-Mg at the interface. With the evidence of grain refinement effect observed in the sheared AZ91D magnesium alloy, the possibility of MgO particles to act as potent nucleants for heterogeneous nucleation of α-Mg grains is discussed in terms of the crystallographic criterion.