情绪体验影响估算策略运用的认知与脑机制

揭示情绪体验影响个体完成各种认知任务的认知神经机制是研究者关注的热点问题。以往研究主要采用问卷法和行为实验, 集中考察了焦虑对估算策略运用的影响, 但这种影响潜在的脑机制尚不清楚, 对焦虑以外的情绪体验与估算策略运用之间关系的研究也极其缺乏, 而情绪调节对估算策略运用影响方面的研究基本处于空白。本研究将采用面孔表情图片作为情绪刺激材料, 结合事件相关电位(event related potential, ERP)技术, 采用启动范式, 尝试从外显和内隐两个角度, 考察不同效价的情绪体验在估算策略运用过程中所起的作用, 进而揭示情绪调节影响估算策略执行的时间动态特征和大脑激活模式。这将有助于充分认识情绪体验影响估算策略运用的认知与脑机制, 为更好的优化估算策略运用效果提供实证依据。     

视觉空间注意的事件相关电位研究

视觉空间注意是心理学多年来一直探讨的问题,也是近来多学科共同关注的领域。在脑机制研究中,事件相关电位(ERP)的研究方法具有高时间分辨率的特点,近年来高密度记录技术的发展,也提高了ERP在功能定位方面的作用,因此其应用日益广泛。该文概述了近年来有关ERP在视觉空间注意研究中的实验方法、结果和初步结论,并就今后研究方向提出了几点看法。     

固定位置区域提示下视觉注意范围等级的ERP研究

研究视觉空间注意中注意范围的脑内时程的动态变化。被试为 14名青年人 ,使用固定位置的、3种不同直径的线圈作为注意范围的区域性提示 ,祛除空间定位因素的影响 ,记录反应时和事件相关电位 (ERP)数据。结果显示 :提示范围由小到中等时 ,反应时延长 ,而由中等到大范围时 ,反应时缩短 ;提示物和靶刺激诱发ERP的早成分 (N1、P1)不受提示范围大小的调节 ,而其P2、N2的波幅与潜伏期均明显受到提示范围大小的影响。这些结果说明 :①视觉注意诱发的P1、N1成分 ,主要与空间定位信息的加工相关 ;②提示物诱发的P2、N2成分与注意范围相关 ;③在视觉信息加工过程中 ,空间位置的信息要早于其它信息被加工 ,支持视觉信息串行加工观点     

位置提示下视觉注意范围的调控机制

研究视觉空间注意中不同注意范围引起脑内加工时程的动态变化。使用固定位置的、三种不同直径的线圈作为注意范围的位置性提示,祛除空间定位因素的影响,记录反应时和事件相关电位（ERP）数据。结果显示：在同等注意范围时,随着刺激位置远离视野中心,反应时延长,靶刺激诱发的P1、N1不受刺激位置的影响,而其前部N2的波幅明显受到刺激位置的影响;在靶刺激位置相同时,随着注意范围的扩大,反应时缩短,靶刺激诱发的P1、N1不受提示范围大小的影响,而其前部P2的波幅明显受到注意范围的影响。结果说明：①视觉注意范围信息加工与靶刺激诱发的P2成分相关;②视觉注意诱发的P1、N1成分,主要与注意方位相关,而与注意范围大小无关;③注意范围变化引起注意集中度的调节是在一定范围内进行的。     

Glucose regulation and face recognition deficits in older adults: the role of attention

The present study investigated the perceptual, attentional, and memory processes underlying face recognition deficits observed in older adults with impaired glucoregulation. Participants were categorized as good glucoregulators or poor glucoregulators on the basis of an oral glucose tolerance test. Using event-related potential (ERP) methodology, 23 participants (62–88 years) performed a 2-stimulus oddball task. Participants were asked to rate and memorize 10 “target” faces, which were then presented amongst 120 unfamiliar foils. Behavioral results indicated that good glucoregulators were significantly more accurate at recognizing target faces. ERP markers of early visual perception (P1 and N170 components) and memory formation (P3 component) were unaffected by glucoregulatory efficiency. The P2 component, an index of attentional processing, was larger and delayed in the poor glucoregulators. To the best of our knowledge, this study is the first to suggest that face recognition deficits in poor glucoregulators may be due to impairments in attentional processing.     

Anticipatory attention during the sleep onset period

To examine whether anticipatory attention or expectancy is a cognitive process that is automatic or requires conscious control, we employed a paired-stimulus event-related potential (ERP) paradigm during the transition to sleep. The slow negative ERP wave observed between two successive stimuli, the Contingent Negative Variation (CNV), reflects attention and expectancy to the second stimulus. Thirteen good sleepers were instructed to respond to the second stimulus in a pair during waking sessions. In a non-response paradigm modified for sleep, participants then fell asleep while tones played. As expected, N1 decreased and P2 increased in amplitude systematically with the loss of consciousness at sleep onset; the CNV was increasingly more positive. Sleep onset latency was correlated with the amplitude of the CNV. The systematic attenuation of the CNV waveform at sleep onset and its absence in sleep indicates that anticipatory attention requires endogenous conscious control.     

Accelerative and decelerative effects of hedonic valence and emotional arousal during visual scene processing

Perceptual processing of natural scene pictures is enhanced when the scene conveys emotional content. Such “motivated attention” to pleasant and unpleasant pictures has been shown to improve identification accuracy in non-speeded behavioural tasks. An open question is whether emotional content also modulates the speed of visual scene processing. In the present studies we show that unpleasant content reliably slowed two-choice categorization of pictures, irrespective of physical image properties, perceptual complexity, and categorization instructions. Conversely, pleasant content did not slow or even accelerated choice reactions, relative to neutral scenes. As indicated by lateralized readiness potentials, these effects occurred at cognitive processing rather than motor preparation/execution stages. Specifically, analysis of event-related potentials showed a prolongation of early scene discrimination for stimuli perceived as emotionally arousing, regardless of valence, and reflected in delayed peaks of the N1 component. In contrast, the timing of other processing steps, reflected in the P2 and late positive potential components and presumably related to post-discriminatory processes such as stimulus–response mapping, appeared to be determined by hedonic valence, with more pleasant scenes eliciting faster processing. Consistent with this model, varying arousal (low/high) within the emotional categories mediated the effects of valence on choice reaction speed. Functionally, arousal may prolong stimulus analysis in order to prevent erroneous and potentially harmful decisions. Pleasantness may act as a safety signal allowing rapid initiation of overt responses.     

Getting connected: Both associative and semantic links structure semantic memory for newly learned persons

The present study examined whether semantic memory for newly learned people is structured by visual co-occurrence, shared semantics, or both. Participants were trained with pairs of simultaneously presented (i.e., co-occurring) preexperimentally unfamiliar faces, which either did or did not share additionally provided semantic information (occupation, place of living, etc.). Semantic information could also be shared between faces that did not co-occur. A subsequent priming experiment revealed faster responses for both co-occurrence/no shared semantics and no co-occurrence/shared semantics conditions, than for an unrelated condition. Strikingly, priming was strongest in the co-occurrence/shared semantics condition, suggesting additive effects of these factors. Additional analysis of event-related brain potentials yielded priming in the N400 component only for combined effects of visual co-occurrence and shared semantics, with more positive amplitudes in this than in the unrelated condition. Overall, these findings suggest that both semantic relatedness and visual co-occurrence are important when novel information is integrated into person-related semantic memory.     

Separating item-related electrophysiological indices of retrieval effort and retrieval orientation

The relationship between two classes of retrieval process-retrieval orientation and retrieval effort-was investigated using electrophysiological (ERP) and behavioural measures. ERPs were recorded during retrieval phases of exclusion tasks in which participants focused on retrieval of either phonological or semantic associates that were generated in a prior study phase. Participants were separated into two groups on the basis of the relative accuracy of their memory judgments in the retrieval tasks (high vs. low relative difficulty) as a means of assessing retrieval effort. The critical contrasts were between the ERPs evoked by unstudied test items separated according to group and emphasis of the retrieval task (semantic vs. phonological). Reliable differences according to task were evident in the high relative difficulty group only. This finding is consistent with the view that, for this task pair at least, ERPs are sensitive to the processes set in train in pursuit of task relevant information (retrieval orientations) only when relative difficulty is high.