情绪加工的性别差异及神经机制

已有研究表明, 情绪加工存在显著性别差异。这主要表现为女性人群具有情绪识别优势, 更好的情绪记忆能力与更强的负性情绪易感性。此外, 情绪加工的性别差异也表现为情绪调节过程的不同：相比男性, 女性更善于抑制情绪行为, 却较难通过认知策略调节负性情绪。情绪加工的性别差异有重要生理基础, 与情绪脑结构, 荷尔蒙水平的男女差异有关。同时, 情绪加工的性别差异同女性更高的情绪障碍易感性有着密切联系：不善于调节负性情绪, 及更强的消极情绪易感性可能是女性更易患情绪障碍的重要原因。从情绪加工角度探讨情绪障碍的性别差异及其原因, 对于情绪障碍的预防和治疗具有重要意义。     

情绪加工中杏仁核的效价特异性

杏仁核是情绪信息加工的关键脑区。近年来心理学和神经科学领域发现了杏仁核情绪加工的效价特异性现象,并且整体存在左侧杏仁核对正性情绪、右侧杏仁核对负性情绪以及双侧杏仁核负性偏好的特异性趋势,且受到材料突出特征、个体差异、任务条件的调节。未来可进一步探索注意对杏仁核情绪效价特异性的调节作用,探究动态情绪刺激加工时杏仁核的活动特点,考察心理障碍患者加工负性情绪时的杏仁核激活模式,并确定杏仁核的效价特异性在思维、计划、决策等高级认知过程中的表现。     

右腹外侧前额叶对高抑郁水平成年人社会情绪调节的作用：一项tDCS研究

已有的经颅直流电刺激(transcranial direct current stimulation, tDCS)研究证明, 右腹外侧前额叶(right ventrolateral prefrontal cortex, RVLPFC)是社会情绪调节的重要脑区, 激活RVLPFC可显著降低人们对社会性负性情绪体验的强度。社会功能受损是抑郁症患者或抑郁倾向人群的重要特征之一。该群体对社会排斥的敏感性高, 且对负性社会情绪体验的情绪调节能力降低。在本研究中, 我们采用外显的情绪调节任务, 研究了高、低抑郁水平的两组成年人被试在RVLPFC接受阳性tDCS后其情绪调节能力的改变。结果表明, 虽然采用tDCS激活RVLPFC可帮助被试通过情绪调节(认知重评)减弱负性情绪体验, 但高抑郁水平被试的负性情绪强度下降程度明显小于低抑郁水平被试。另外本文还发现, 与源于个人的负性情绪相比, tDCS效应对源于社会的负性情绪(即社会排斥)更强。本研究是采用电或磁刺激提高抑郁人群社会情绪调节能力的首次尝试。实验结果表明, 高抑郁水平成年人的RVLPFC仅通过单次、短时间(34 min)的tDCS激活, 其情绪调节能力并未得到显著提升。这提示对抑郁倾向群体或抑郁症患者的干预或治疗需要多次施加tDCS。     

认知重评的创造性对负性情绪调节的影响

以轻度负性图片为实验材料,采用自发性和指导性的认知重评策略,结合情绪的主观评定和生理指标,考察认知重评的创造性对负性情绪调节的影响,以及特质焦虑是否在其中起调节作用。结果发现：(1)自评和他评的认知重评创造性与情绪调节有效性呈显著正相关;(2)相比低创造性的认知重评,高创造性的认知重评对负性情绪的调节效果更好,并伴随着适应性的生理反应,皮电和心率显著下降;(3)相比低特质焦虑个体,高特质焦虑个体更容易体验到高负性情绪,但经过认知重评后两者的情绪调节效果无显著差异。结果表明,创造性认知重评促进负性情绪调节,特质焦虑在创造性认知重评与负性情绪调节之间不起调节作用。结果支持认知重评的创造性重构理论。     

认知重评策略对注意分配的影响

认知重评是采用对当前刺激情境的意义进行重新解释来改变情绪体验的情绪调节策略。该研究以31名大学生为被试,采用负性情绪图片作为刺激材料,2(是否认知重评:被动观看、认知重评)×2(情绪词:中性词、负性词)的两因素完全被试内设计,考察认知重评对情绪体验的调节作用是否通过影响对注意的分配来实现的。结果发现:(1)认知重评条件下负性情绪体验的强度比被动观看条件下显著降低。(2)对于中性词,认知重评阶段的反应时显著快于被动观看阶段,t(29)=-5.09,p0.01。而对于负性词,认知重评阶段的反应时显著长于被动观看阶段,t(29)=2.43,p0.05。以上结果说明,认知重评的情绪调节策略可以通过减弱对负性刺激的注意偏向来降低负性情绪体验。     

唤醒定义探析及其认知神经生理基础

唤醒是衡量机体清醒程度和做出反应前准备程度的指标, 其水平可从睡眠到觉醒的连续体上变化, 具有独特的生理机制与神经回路。由于唤醒与情绪关联密切, 唤醒度这个概念常被认为等同于情绪强度, 但情绪强度实际上是唤醒和效价的和向量。受到Lazarus提出的“刺激”定义情绪思想的启发, 对唤醒的内含和心理机制进行了探析, 发现对不符合预期刺激出现的紧急准备是唤醒系统的主要功能, 预期性相关机制是唤醒的重要认知加工机制。其它因素(刺激属性、个体差异等)可能存在以下影响唤醒的原因：改变处理刺激时所需的资源量、影响预期机制。未来研究可从心理唤醒与生理唤醒的关系、唤醒的测量方法、唤醒度与情绪强度的关系、人类临床精神疾病的唤醒特征等角度推动唤醒的基础和应用研究。     

负性情绪强度对双加工再认提取的影响

双加工理论认为再认提取存在回想和熟悉性两种认知加工过程。本研究采用修正的“记得/知道”范式,考察不同强度的负性情绪对这两种再认提取过程的影响。结果发现：（1）在记得反应上不同负性情绪强度的材料呈现出以下模式：高度负性 > 中度负性 > 轻度负性 > 中性;（2）在知道反应上,不同负性情绪强度的材料呈现出以下模式：中性 > 轻度负性 > 中度负性 > 高度负性。这些结果表明,不同强度的负性材料对情绪记忆的影响表现为两条途径：依赖于回想的再认随着负性情绪强度的增加而逐步提高,另外一个依赖于熟悉性的再认随着负性情绪强度的增加而逐步降低。     

情绪性场景图片加工的ERP研究:成果与问题

近年来,以情绪性场景图片做为刺激进行事件相关电位(ERP)的研究越来越多。特别是情绪效价效应和唤醒效应在相关ERP成分(P1、P2、EPN、N2、P300和正性慢波)上的反映更是情绪研究的一个热点。情绪效价ERP效应的研究主要集中在对情绪负性偏向的研究上,唤醒效应反映了情绪的动机作用。然而,情绪性场景图片加工的ERP研究结果存在许多不一致,这些不一致可能源于注意资源、图片评定、图片内容、刺激物理特征、任务、个体差异等因素的影响。如何将行为结果、非情绪ERP证据、情绪ERP证据结合起来,对不同神经生理学方法和刺激类型加以整合,尚需很长的路要走。     

负性情绪调节中认知重评和分心策略的作用:ERPs研究

采用事件相关电位技术,考察了认知重评和分心两种情绪调节策略对负性情绪体验和脑电活动的影响。结果发现,认知重评后被试的负性情绪体验强度和LPP波幅(300~1300ms)比简单注视条件下低;分心后被试的负性情绪体验强度比简单注视条件下低,但LPP波幅显示比简单注视条件下高。这说明认知重评和分心对负性情绪体验和脑电活动的影响不同,负性刺激再次呈现时认知重评优于分心策略的调节。该研究为认知重评和分心的比较研究提供了神经电生理学方面的证据。     

情绪启动与语义启动的比较

情绪启动与语义启动发生时孰先孰后、进行中独立平行还是交互作用、效应上孰强孰弱,还存在较大争议.这些争议的本质涉及到人脑中情绪和认知这两大基本系统的关系认识问题.通过行为观察与事件相关脑电位技术结合,在同一个实验中设置情绪启动、语义启动两种情境,并匹配可能影响这两种启动效应的因素,如信息强度、启动刺激和靶刺激的信息关联程度等,然后系统性变化启动刺激呈现的时间、SOA、实验任务等,并逐步加入被试的年龄、性别、学科专业、认知风格、情绪易感性等个体差异变量,可望直接而系统地澄清争议,深层次揭示情绪信息流与语义信息流的加工特点,并进而揭示人脑情绪系统与认知系统功能与机制的发展规律.     

Event-related potentials of emotional memory: encoding pleasant,unpleasant, and neutral pictures

Emotional events tend to be remembered better than nonemotional events. We investigated this phenomenon by measuring two event-related potential (ERP) effects: the emotion effect (more positive ERPs for pleasant or unpleasant stimuli than for neutral stimuli) and the subsequent memory effect (more positive ERPs for subsequently remembered items than for subsequently forgotten items). ERPs were measured while subjects rated the emotional content of pleasant, unpleasant, and neutral pictures. As was expected, subsequent recall was better for pleasant and unpleasant pictures than for neutral pictures. The emotion effect was sensitive to arousal in parietal electrodes and to both arousal and valence in frontocentral electrodes. The subsequent memory effect at centroparietal electrodes was greater for emotional pictures than for neutral pictures during an early epoch (400-600 msec). This result suggests that emotional information has privileged access to processing resources, possibly leading to better memory formation.     

Catechol-O-methyltransferase Val158Met genotype affects neural correlates of aversive stimuli processing

It was previously shown that variation of the catechol-O-methyltransferase (COMT) gene modulates brain activity during the processing of stimuli with negative valence, but not for pleasant stimuli. Here, we tested whether the COMT genotype also modulates the electrophysiological correlates of emotional processing and explored whether the environmental factor of life stress influences this effect. Using the early posterior negativity (EPN) paradigm, event-related brain potentials were measured in 81 healthy individuals during the processing of pictures that evoked emotions of positive and negative valence. As was hypothesized, the COMT genotype affected the EPN amplitudes for unpleasant stimuli, but not for pleasant ones. Specifically, Met/Met carriers respond more sensitively to unpleasant stimuli, as compared with Val/Val carriers. We did not find evidence that life stress moderates the effect of the COMT genotype on emotional stimuli processing.     

Neural mechanisms underlying the higher levels of subjective well-being in extraverts: Pleasant bias and unpleasant resistance

The present study investigated the neural mechanisms that underlie the higher levels of subjective well-being in extraverts. The impact of extraversion on the human sensitivity to pleasant and unpleasant pictures of diverse emotional intensities was examined. We recorded event-related potentials (ERPs) for highly positive (HP), moderately positive (MP), and neutral stimuli in the pleasant session, and for highly negative (HN), moderately negative (MN), and neutral stimuli in the unpleasant session, while subjects (16 extraverts and 16 ambiverts) performed a standard/deviant categorization task, irrespective of the emotionality of the deviant stimuli. The results showed significant emotion effects for HP and MP stimuli at the P2 and P3 components in extraverts, but not in ambiverts. Despite a pronounced emotion effect for HN stimuli across the P2, N2, and P3 components in both samples, ambiverts displayed a significant emotion effect for MN stimuli at the N2 and P3 components that was absent in extraverts. The posterior cingulate cortices, which connect multiple neural regions that are important in interactions of emotion and extraversion, may mediate the extravert-specific emotion effect for pleasant stimuli. Thus, extraverts are less susceptible to unpleasant stimuli of mild intensity than are ambiverts, while extraverts have an additional enhanced sensitivity to pleasant stimuli, regardless of emotion intensity. Consequently, the decreased threshold for pleasant emotion and the increased threshold for unpleasant emotion might be essential neural mechanisms that underlie the higher levels of subjective well-being in extraverts.     

Emotion-modulated performance and activity in left dorsolateral prefrontal cortex

Functional MRI (fMRI) was used to examine the relationship between processing of pleasant and unpleasant stimuli and activity in prefrontal cortex. Twenty volunteers identified the colors in which pleasant, neutral, and unpleasant words were printed. Pleasant words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant words. In addition, pleasant words prompted more activity in left than in right DLPFC. Response speed to pleasant words was correlated with DLPFC activity. These data directly link positive affect, enhanced performance, and prefrontal activity, providing some of the first fMRI evidence supporting models of emotional valence and frontal brain asymmetry based on electroencephalography (EEG).     

Vivid: How valence and arousal influence word processing under different task demands

In this study, we used event-related potentials to examine how different dimensions of emotion—valence and arousal—influence different stages of word processing under different task demands. In two experiments, two groups of participants viewed the same single emotional and neutral words while carrying out different tasks. In both experiments, valence (pleasant, unpleasant, and neutral) was fully crossed with arousal (high and low). We found that the task made a substantial contribution to how valence and arousal modulated the late positive complex (LPC), which is thought to reflect sustained evaluative processing (particularly of emotional stimuli). When participants performed a semantic categorization task in which emotion was not directly relevant to task performance, the LPC showed a larger amplitude for high-arousal than for low-arousal words, but no effect of valence. In contrast, when participants performed an overt valence categorization task, the LPC showed a large effect of valence (with unpleasant words eliciting the largest positivity), but no effect of arousal. These data show not only that valence and arousal act independently to influence word processing, but that their relative contributions to prolonged evaluative neural processes are strongly influenced by the situational demands (and by individual differences, as revealed in a subsequent analysis of subjective judgments).     

Effects on incidental memory of affective tone in associated past and future episodes: influence of emotional intelligence

The present study examined the effects of emotion elicited by episodes (past events or expected future events) and the relationship between individual differences in emotional intelligence and memory. Participants' emotional intelligence was assessed on the Japanese version of Emotional Skills and Competence Questionnaire. They rated the pleasantness of episodes they associated with targets, and then performed unexpected free recall tests. When the targets were associated with episodes that were past events, all participants recalled more of the targets associated with pleasant and unpleasant episodes than those associated with neutral episodes. However, when the targets were associated with episodes expected to occur in the future, only participants with higher emotional intelligence scores recalled more of the targets associated with pleasant and unpleasant episodes. The participants with lower emotional intelligence scores recalled the three target types with similar accuracy. These results were interpreted as showing that emotional intelligence is associated with the processing of targets associated with future episodes as retrieval cues.     

An increase in stimulus arousal has differential effects on the processing speed of pleasant and unpleasant stimuli

The arousal value of a stimulus influences its salience, whereby higher arousal should lead to faster processing. However, in previous research, participants consistently made faster valence judgments for low arousal, pleasant stimuli than for high arousal, pleasant stimuli. The speed of valence and arousal judgments for pictures and words were investigated in three experiments. Valence judgments were faster for low arousal than for high arousal pleasant pictures and for high arousal than for low arousal unpleasant pictures and words. Moreover, arousal judgments were faster for low arousal than high arousal pleasant and for high arousal than low arousal unpleasant pictures and words. The current research confirms that the impact of valence and arousal on processing speed does not reflect on the labels (valence versus arousal) used when recording speeded judgments. Similarly to valence, stimulus arousal interacts differentially with the evaluation of pleasant and unpleasant stimuli producing a processing advantage for high arousal, unpleasant stimuli but not high arousal, pleasant stimuli.     

Early modulation of visual perception by emotional arousal: Evidence from steady-state visual evoked brain potentials

Allocation of processing resources to emotional picture stimuli was examined using steady-state visual evoked brain potentials (ssVEPs). Participants viewed a set of 60 colored affective pictures from the International Affective Picture System, presented in a flickering mode at 10 Hz in order to elicit ssVEPs. Phase and amplitude of the 10-Hz ssVEP were examined for six picture categories: threat and mutilation (unpleasant), families and erotica (pleasant), and household objects and persons (neutral). Self-reported affective arousal and hedonic valence of the picture stimuli were assessed by means of subjective ratings. Viewing affectively arousing (unpleasant and pleasant) pictures was associated with enhanced ssVEP amplitude at parieto-occipital recording sites, as compared with neutral stimuli. Phase information suggested increased coactivation of right occipitotemporal and frontotemporal sources during processing of affectively arousing stimuli. These findings are consistent with reentrant modulation of early visual processing by distributed networks including subcortical and neocortical structures according to a stimulus's motivational relevance.     

The persistence of attention to emotion: brain potentials during and after picture presentation

Emotional stimuli have been shown to elicit increased perceptual processing and attentional allocation. The late positive potential (LPP) is a sustained P300-like component of the event-related potential that is enhanced after the presentation of pleasant and unpleasant pictures as compared with neutral pictures. In this study, the LPP was measured using dense array electroencephalograph both before and after pleasant, neutral, and unpleasant images to examine the time course of attentional allocation toward emotional stimuli. Results from 17 participants confirmed that the LPP was larger after emotional than neutral images and that this effect persisted for 800 ms after pleasant picture offset and at least 1,000 ms after unpleasant picture offset. The persistence of increased attention after unpleasant compared to pleasant stimuli is consistent with the existence of a negativity bias. Overall, these results indicate that attentional capture of emotion continues well beyond picture presentation and that this can be measured with the LPP. Implications and directions for future research are discussed.