面孔识别过程中种族信息的提取:神经机制与认知特点

目的:调查面孔识别中的异族效应,检测人脸加工过程中种族信息的感知方式.方法:本研究提供了一种新的实验范式和方法,专门检测种族识别的神经机制.平均多张相同种族的面孔以突显面孔的种族信息,改变这些平均面孔的变形程度来操纵被试对种族信息的判断,然后采用多体素模式分析的方法检测种族认知的完整神经过程.结果:约在300ms之...     

萘哌地尔衍生物YMII的扩血管效应及机制研究

目的：研究萘哌地尔衍生物YMII对离体家兔胸主动脉的松弛作用及其机制。方法：1．应用血管平滑肌等张收缩的方法．观察YMII对去甲肾上腺素(NA)、高钾及5-羟色胺(5-HT)量效曲线的影响。2．应用无Ca^2 -复Ca^2 的实验方法．以NA和咖啡因(Caffeine)为激动剂．间接观察YMII对细胞内游离钙浓度([Ca^2 ]i)的影响。结果：YMII呈浓度依赖性地松弛NA、KCL及5-HT预收缩的离体家兔胸主动脉螺旋条．其中以对NA所致血管条收缩的抑制作用为强：     

大学生学业困难影响因素及发展过程的质性研究

为探讨大学生学业困难心理发生发展的影响因素及其相互作用机制,对8名达到或接近该校学业试读标准的学生进行深度访谈,采用质性研究方法进行分析.结果显示,大学生学业困难发生发展影响因素可包括始基因素、促进因素、过程因素以及抑制因素四大核心类属,又包括学业基础差、入学懈怠、适应不良、不良替代性偏好、不良人际关系、亲子问题、负性...     

骨代谢过程中白细胞介素1的参与作用及调控机制

背景:研究发现白细胞介素1的两种生物活性相似的同工型白细胞介素1α和白细胞介素1β对骨的代谢会产生重大影响,研究表明它们具有诱导成骨细胞或破骨细胞分化的能力.目的:综述目前已知相关文献,总结白细胞介素1与成骨细胞或破骨细胞的关系,了解白细胞介素1在骨代谢中的作用机制,为新的成骨方案提供理论参考.方法:检索中国知网和Pu...     

培养的血管平滑肌细胞表型转变过程中张力纤维及中间丝变化的扫描电镜观察

为揭示体外培养的血管平滑肌细胞(VSMC)在表型转变过程中张力纤维及中问丝三维构筑的变化，采用Triton消化和扫描电镜技术，对不同表型的VSMC进行了观察。结果证实，收缩型VCSM胞质中含大量平行排列的张力纤维；中间丝则密布于张力纤维之间，形成支撑和连接张力纤维的复杂网络。随着VSMC由收缩型向合成型转变，胞核附近的中间丝逐渐向细胞周边胞质分布，以至核周出现明显的“中问丝稀疏区”。张力纤维亦逐渐分解变细，且在部分合成型VSMC中完全消失。本文对上述变化的可能机制进行了讨论。     

学习过程问卷的结构及信、效度研究

目的：探讨学习过程问卷的结构并检验其信、效度。方法：以Biggs等人的研究为基础，使用雷雳等1997年研究中的学习过程问卷，对756名大学生的测试结果进行探索性和验证性因子分析及信效度检验。结果：探索性及验证性因素分析均支持六因子模型。不支持根据理论建构的其它三个模型；问卷整体内部一致性系数为0．81，间隔六月问卷的稳定性系数为0．70；各因素间的相关在-0．01—0．50之间，各因素与总分间的相关在0．41以上，问卷各题项与其所属因素间相关在0．42以上。结论：本研究支持该问卷的六因素结构，问卷的信效度符合心理测量学的基本要求。但表层动机及表层策略所属个别题项仍需进一步的修改。     

肾小管上皮细胞转分化过程中ILK的表达变化及大黄素对其的干预效应

目的:研究信号蛋白ILK在IL-1β诱导的肾小管上皮细胞-肌成纤维细胞转分化(TEMT)中的表达变化以及大黄素是否是通过抑制ILK的表达而影响IL-1β诱导的肾小管上皮细胞-肌成纤维细胞转分化.方法:以体外培养的正常大鼠肾小管上皮细胞株(NRK52E)为研究对象,分为空白对照组、大黄素对照组、IL-1β诱导组、IL-1β加大黄素组.在倒置相差显微镜下观察细胞形态变化;免疫双标法检测a-平滑肌肌动蛋白(a-SMA)和E-钙黏连素(E-cadherin)的表达;免疫单染检测ILK的表达;ELISA法测定培养细胞分泌的纤维连接蛋白(FN)含量.结果:IL-1β诱导细胞转变为明显类似成纤维细胞形态,增加a-SMA的表达[(65.5±1.7)vs(140.4±3.0),P<0.05],减少E-cadherin的表达[(82.5±1.0)vs(36.0±2.8),P<0.05),促进ILK的表达[(36.1±3.1)vs(82.4±1.2),P<0.05],促进FN的合成[(54.6±3.1)mg/Lvs(124.8±3.2)mg/L,P<0.05],加入大黄素后上述变化受到明显抑制.结论:在IL-1β诱导的TEMT中ILK的表达是明显上调的,大黄素可能通过下调ILK的表达而抑制IL-1β诱导的TEMT.     

汉词再认ERP新旧效应的性别差异

目的：运用事件相关电位（ERPs）技术探讨汉词再认新旧效应的性别差异及其脑机制。方法：30名大学生（男女各半）参与汉词再认测验，同时记录EEG，离线处理数据后比较男女被试诱发出的ERPs主要成分及其新旧效应。结果：女性P500波幅显著大于男性（F=12．76，P〈0．001），潜伏期短于男性（F=3．589，P〈0．05）。男女被试在350．600ms均诱发出了显著的顶区新旧效应，但男性呈显著左侧优势，女性则更为双侧化。仅男性诱发出了显著的额区新旧效应，呈负走向变化，头皮分布呈右侧优势。结论：汉词再认的ERP新旧效应存在性别差异。这种性别差异可能既与信息提取速度及强度的差异有关，也与不同性别的神经解剖结构差异有关。     

Effects of Inter-Item Lag on Word Repetition: An Event-Related Potential Study

Prior exposure to a word can greatly facilitate performance to subsequent presentations of that word. ERP studies have shown that this facilitation is associated with an attenuation of a negative peak normally occurring around 400 ms poststimulus. Recent studies have interpreted this repetition effect as reflecting either lexical access or episodic memory mechanisms. However, there is now increasing evidence that neither of the above mechanisms alone can fully account for repetition effects. The present experiment recorded ERPs to immediate and delayed word repetition during a lexical decision task in order to investigate the time-course of ERP repetition effects. Immediate repetition was found to produce greater response facilitation than delayed repetition. The ERP waveforms of both immediate and delayed word repetition diverged from that of initial word presentation at approximately 300 ms poststimulus. The waveforms for repeated words separated around 400 ms poststimulus with immediate repetition showing a more rapid resolution of negativity and earlier late positivity than delayed repetition. It is suggested that the negativity may reflect processes involved in the overall activation contributing to word recognition, whereas the late positivity may be related to the repetition of stimulus categorization and decision processes.     

中文听觉双字词认知中的正字法即时激活效应——来自ERP的证据

目的:探讨中文听觉双字词认知中的正字法即时激活效应.方法:采用事件相关电位(ERP)技术,操纵3种双字词条件(一致性:一致、首字不一致、尾字不一致),选择9个电极,使用时间窗分析技术,以50ms为一个时间窗分析300-350ms以及375-675ms时段的脑电波.结果:对前部脑电波平均波幅进行方差分析发现,三种实验条件在575-625ms时间窗差异显著,而在625-675ms时间窗差异边缘显著.首字不一致和一致条件在575-625ms时间窗差异显著,而在625-675ms时间窗差异边缘显著.结论:在中文听觉双字词认知中可能同样存在正字法即时激活效应.     

Earthquake experience interference effects in a modified Stroop task: An ERP study

The effects of the modified Stroop task on ERP were investigated in 20 subjects who had experienced the Sichuan earthquake and a matched control group. ERP data showed that Incongruent stimuli elicited a more negative ERP deflection (N300–450) than did Congruent stimuli between 300 and 450 ms post-stimulus in the earthquake group but not found in the control group, and the N300–450 might reflect conflict monitor (the information of color and meaning do not match) in the early phase of perception identification due to their sensitivity to the external stimulus. Then, Incongruent stimuli elicited a more negative ERP deflection than did Congruent stimuli between 450 and 650 ms post-stimulus in both the groups. Dipole source analysis showed that the N450–650 was mainly generated in the ACC contributed to this effect in the control group, which might be related to monitor and conflict resolution. However, in the earthquake group, the N450–650 was generated in the thalamus, which might be involved in inhibiting and compensating of the ACC which may be related to conflict resolution process.     

Neural mechanisms of subliminal priming for traumatic episodic memory: An ERP study

Event-related brain potentials (ERPs) were measured to study the electrophysiological mechanisms of subliminal priming of traumatic episodic memory. Twenty-four Chinese subjects who had experienced the great Sichuan earthquake in 2008 were classified either as normal control or as post-traumatic stress disorder (PTSD) subjects. Results showed that subliminally presented earthquake-related words elicited two significantly more positive ERP deflections (P2 and P300) than did earthquake-unrelated words between 250–300 ms and 340–400 ms post-stimulus periods for the PTSD group, but not for the control group. Dipole source analysis showed that the P2 was mainly generated in the posterior cingulate cortex (PCC), which appeared to be related to unconscious attentional resource allocation to the earthquake-related words. In addition, the P300 was found to be generated in the parahippocampal gyrus, which seemed to be related to the involuntary activation of traumatic episodic memory. These results indicated that catastrophic earthquake experiences made some subjects extremely sensitive and hyper-responsive to trauma-related information.     

Dissociating love-related attention from task-related attention: An event-related potential oddball study

The present event-related potential (ERP) study was conducted to investigate the P3 component in response to love-related stimuli while controlling for task-related factors, and to dissociate the influences of both love-related and task-related attention on the P3 amplitude. In an oddball paradigm, photographs of beloved and friends served as target and distractor stimuli. Love-related and task-related attention were separated by varying the target and distractor status of the beloved and friends full factorially. As expected, the P3 amplitude was larger for beloved compared to friends and for targets compared to distractors. Moreover, task-related and love-related attention were unconfounded. These results are in line with findings that the P3 is modulated by both emotion- and task-related factors, supporting the view that the P3 amplitude reflects attention. Furthermore, this study validates the notion that romantic love is accompanied by increased attention for stimuli associated with the beloved, and also shows that this form of attention is different from task-related attention.     

Ambiguous words in sentences: brain indices for native and non-native disambiguation

In the present study, we compare how native speakers and second language learners process homonyms (such as bank and jam) in sentence context during a late processing phase that involves selection of the appropriate meaning. With both participant groups, we conducted a combined reaction time (RT)/event-related brain potential (ERP) lexical decision experiment with a long stimulus-onset asynchrony (SOA) of 800 ms. Related primes were homonyms at the end of sentences with a context biasing one of the homonym meanings, and targets reflected the contextually appropriate or inappropriate meaning. Both RT and ERP semantic priming in the N400 component revealed that for both natives and learners, only contextually appropriate meanings were primed, or still active, late in processing. The results indicate that L2 learners show similar, though slower, homonym processing mechanisms to those of native speakers of a language, and that both groups can achieve disambiguation based on semantic context.     

Dissociation of visual C1 and P1 components as a function of attentional load: An event-related potential study

The earliest cortical location at which attention influences visual processing is controversial. To address this issue, the C1 and P1 components of cue-elicited ERPs were examined in a spatially-cued task under high and low levels of attentional load (active vs. passive viewing). Cues were presented either to the left or to the right visual field in separate trials (unilateral presentation), or to both visual fields simultaneously (bilateral presentation). For the unilateral presentation, C1 (peak latency approximately 80 ms) was not modulated by attentional load, whereas P1 (peak latency approximately 120-140 ms) was larger for high-relative to low-load condition. Bilateral presentation of the stimuli enhanced the amplitude of the C1 component relative to unilateral presentation; however, the increase of signal/noise ratio of C1 revealed no attentional load effect on C1. Results show that attentional load modulates visual processing in the P1, but not in the C1 time range, regardless of the increased signal/noise ratio by bilateral presentation. While it remains unclear about the conditions under which a C1 attentional effect is reliably elicited, the present results suggest that the direct manipulation of attentional load under a voluntary attention task seems not crucial for eliciting C1 attentional effect.     

积极情绪对整体和局部知觉的影响:事件相关电位研究

目的:采用启动范式和事件相关电位方法,研究积极情绪如何调制视觉系统选择性加工刺激整体特征和局部特征的神经机制。方法:对22名大学生,采用Neuroscan公司64导脑电系统记录其在3种情绪图片启动条件下执行整体和局部加工任务时的事件相关电位(ERPs)和行为学结果。结果:250～320ms时间段内,积极情绪和中性情绪启动条件下整体加工引起的事件相关脑电波幅大于局部加工的脑电波幅(P<0.01),差异主要分布于额-中央区;350～500ms时间段内,积极情绪启动的整体加工(局部加工)诱发的事件相关脑电波幅大于消极情绪启动的整体加工(局部加工)诱发的脑电波幅(P<0.01),差异主要分布于顶-枕区。结论:积极情绪促进整体和局部知觉加工的神经机制,可能存在差别,ERP早期成分的差异可能与额-中央区活动关系密切,晚期成分与顶-枕区活动联系可能更为密切。     

Event-related potentials differentiates the processes involved in the effects of sleep on recognition memory

This study examined the role of sleep on event-related potential (ERP) indicators of memory following sleep and wake. We expected a larger ERP effect due to a facilitory effect of sleep on memory. During the study session, subjects memorized a series of stimuli (faces). At test, after a retention interval characterized by either sleep or by normal waking activities, subjects were asked to recognize old items intermixed with new. Results revealed differences in the old/new effect whereby the amplitude between old/new items was larger after sleep versus wake, suggesting a role of sleep in consolidation. Retention over sleep versus wake was associated with modified early and late frontal and posterior components possibly manifesting reduced interference inhibition, increased contextual processing, and facilitation of episodic memory. These findings suggest that ERP indices are differentially affected by sleep, reflecting differences in memory processing.