Event-related brain potential correlates of the other-race effect: A review

People are better at remembering own-race relative to other-race faces. Here, we review event-related brain potential (ERP) correlates of this so-called other-‘race’ effect (ORE) by discussing three critical aspects that characterize the neural signature of this phenomenon. First, difficulties with other-race faces initially emerge during perceptual processing, which is indexed by an increased N170. Second, as evidenced by ‘difference due to subsequent memory’ effects, more effortful processing of other-race faces is needed for successful encoding into long-term memory. Third, ERP old/new effects reveal that a stronger engagement of processing resources is also required for successful retrieval of other-race faces from memory. The ERP evidence available to date thus suggests widespread ethnicity-related modulations during both perceptual and mnemonic processing stages. We further discuss how findings from the ORE compared with potentially related memory biases (e.g. other-gender or other-age effects) and how ERP findings inform the ongoing debate regarding the mechanisms underlying the ORE. Finally, we outline open questions and potential future directions with an emphasis on using multiple, ecologically more valid ‘ambient’ images for each face to assess the ORE in paradigms that capture identity rather than image recognition.     

Attention affects the recognition of briefly presented visual stimuli in infants: an ERP study

This study examined the effect of attention in infants on the ERP changes occurring during the recognition of briefly presented visual stimuli. Infants at ages 4.5, 6 and 7.5 months were presented with a Sesame Street movie that elicited periods of attention and inattention, and computer-generated stimuli were presented overlaid on the movie for 500 ms. One stimulus was familiar to the infants and was presented frequently, a second stimulus was familiar but presented infrequently, and a set of 14 novel stimuli were presented infrequently. An ERP component labeled the 'Nc' (Negative Central, about 450-550 ms after stimulus onset) was larger during attention than inattention and increased in magnitude over the three testing ages during attention. Late slow waves in the ERP (from 1000 to 2000 ms post-stimulus onset) consisted of a positive slow wave in response to the infrequent familiar stimulus at all three testing ages. The late slow wave in response to the infrequent novel stimulus during attention was a positive slow wave for the 4.5-month-old infants, to a positive-negative slow wave for the 6-month-old infants and a negative slow wave for the 7.5-month-old infants. These results show attention facilitates the brain response during infant recognition memory and show that developmental changes in recognition memory are closely related to changes in attention.     

Endogenous Covert Spatial Orienting in Audition Cost-Benefit Analyses of Reaction Times and Event related Potentials

The presentstudy examines mechanisms ofendogenous covertspatialorienting inaudition as revealed by event-related brain potentials (ERPs) and reaction times (RTs). In one experimental condition, subjects were instructed to respond to any target tone irrespective of whether it was presented in a valid (spatially predictive cue), neutral (uninformative cue), or invalid (misleading cue) trial. In another experimental condition, only target tones presented at a cued position required a response-that is, subjects could completely ignore tones presented at the uncued ear. Cue validity had an effect on RT, which consisted in benefits for valid trials and in costs for invalid trials relative to the RTs in neutral trials. There were also distinct ERP effects of cue validity in the 100-300 msec time range. These ERP effects were enlarged in the condition in which uncued tones could be ignored. The effects of cue validity onRTsandERPsdemonstratedcovertorientinginauditionbothforstimulirequiring anovert response andalso for stimuli that did not require a behavioural response. It is argued that this attentional selection is located at intermediate stages of information processing, rather than at peripheral stages such as basic sensory-specific processing or response selection.     

Unitization mitigates interference by intrinsic negative emotion in familiarity and recollection of associative memory: Electrophysiological evidence

Emotion exerts varied influences on memory. While task-relevant item memory is often enhanced by emotion, associative memory is generally impaired. Unitization is known to improve associative memory, but its effects and mechanisms in protecting associative memory from emotional interference are rather obscure. The current study investigated associative memory by employing experimental manipulation of unitization (vs. nonunitization) encoding strategy and stimulus emotion (neutral, intrinsic negative, and extrinsic negative), combined with event-related potential (ERP) signatures of familiarity (FN400 old/new effects) and recollection (parietal late positive component/LPC old/new effects) in memory recognition. Both behavioral and ERP indices of associative recognition from the nonunitization group confirmed emotional interference in associative memory. Importantly, it was primarily intrinsic (vs. extrinsic) emotion that impeded associative memory. Unitization encoding improved memory performance in general, accompanied by enhanced recollection process and induction of familiarity process, which is typically not involved in associative memory recognition and was indeed absent in the nonunitization group. Importantly, unitization helped to preserve behavioral performance (specifically, response speed though not recognition strength) from interference by intrinsic emotion while largely reversed the detriment of intrinsic emotion on ERP indices of familiarity and recollection processes. Interestingly, a synergy between intrinsic emotion and unitization encoding was observed, which could underpin the facilitation of familiarity process in associative recognition of emotional pairs. Overall, current findings highlight interference by intrinsic emotion in associative memory, which is nonetheless responsive to mitigation by unitization encoding.     

记忆机制中再认的事件相关电位

ERP对于记忆的研究有独到之处,在研究方法是有外显的直接范式和内隐的间接范式,分别表现为ERP新旧效应和重复效应,即在刺激200ms以后的正向偏移.对于记忆提取的ERP效应已有一些理论解释,但在听觉记忆、汉字记忆以及记忆的脑内机制等方面还需要进一步的深入研究.     

Protective role of educational level on episodic memory aging: An event-related potential study

The aim of the present experiment was to investigate whether educational level could modulate the effect of aging on episodic memory and on the electrophysiological correlates of retrieval success. Participants were divided into four groups based on age (young vs. older) and educational level (high vs. low), with 14 participants in each group. Event-related potentials (ERP) were recorded while participants performed a word-stem cued-recall task. Age-related memory deficits were greater for the less educated individuals. Age differences in the ERP old/new effects were also modulated by the level of education. This study demonstrated that the effects of age on episodic memory and ERP correlates of retrieval success are smaller in participants with high educational levels than those with lower levels. These findings provide support for the reserve hypothesis and highlight the need to consider individual differences when studying cognitive and cerebral changes in aging.     

Psychological Flexibility as Shared Process of Change in Acceptance and Commitment Therapy and Exposure and Response Prevention for Obsessive-Compulsive Disorder: A Single Case Design Study

Changes in psychological flexibility were tracked in a combined protocol of exposure and response prevention (ERP) and acceptance and commitment therapy (ACT) for adults with OCD to assess if changes in psychological flexibility processes were unique to ACT intervention (e.g., not impacted by ERP). Using a nonconcurrent multiple baseline design, four participants received sessions of ERP and ACT while data was collected on psychological flexibility processes of change and OCD symptom severity. Results indicate treatment response for three of four participants based on OCD scores. Contrary to predictions, data suggest both ERP and ACT have positive effects on psychological flexibility. Implications of these findings are discussed in relation to recent research on ACT and ERP for OCD. This study also illustrates a type of research design that can be accomplished in clinical practice.     

Interrupted actions affect output monitoring and event-related potentials (ERPs)

Memory for performed and interrupted actions was measured on source recognition and source recall tests in order to investigate output monitoring (i.e., memory for actions). Event-related potentials (ERPs) were recorded during the source recognition test to provide insight into the neural basis of output monitoring (OM). Source identification and recall of performed actions was greater than interrupted actions, thereby replicating the enactment effect. Examination of memory errors revealed that interrupted actions were more often mistaken as performed actions. The ERP data indicated that brain activity elicited by performed actions differed from interrupted and new actions. A clear difference in temporal onset of two ERP effects (i.e., a central-parietal and a frontal ERP difference) was observed, and it supports the previous hypothesis that two distinct processes support OM and source monitoring judgements. The pattern of frontal ERP differences suggested that interrupted actions prompted people to use more systematic decision processes overall to make OM judgements. Central-parietal ERP effects suggested that sensori-motor information was not recollected for interrupted actions--rather OM judgements were based on cognitive operations in this case.     

注意促进效应的ERP研究

近期发现,采用目标探测任务作为二级任务时,目标探测条件不仅不会削弱,甚至会提高记忆成绩,产生注意促进效应（ABE）。为进一步探究目标探测的作用机制,研究采用事件相关电位（ERP）技术,对比目标与分心条件在编码和提取过程中所诱发的ERP差异。结果表明,两类条件在再认过程中所诱发的ERP差异不仅表现在早期与知觉加工相关的ERP成份上,并且一直持续到了后期与细节提取相关的ERP成分上。由此推测,ABE不仅体现在编码早期的知觉加工阶段,更会延续到后期的复述与精加工。     

Neurophysiological indices of free recall memory biases in major depression: The impact of stimulus arousal and valence

This study examined differential impact of the valence and arousal characteristics of stimuli on memory biases and brain activity in major depressive disorder (MDD) and non-depressed control participants. P300 and slow wave (SW) components of the event-related brain potential (ERP) were recorded in 18 MDD and 18 control individuals during the encoding of positive and negative, high and low arousal words in a free recall task. Control participants demonstrated expected enhanced memory for positive stimuli that was accompanied by a corresponding increase in SW ERP components. These effects were not seen in the MDD participants. Rather, memory biases for negative information in MDD were only observed for low arousal words and were not reflected in ERP amplitudes. This study suggests that the inconsistency in the MDD memory bias literature may be related to the arousing nature of the stimuli incorporated in the study.     

Interrupted actions affect output monitoring and event-related potentials (ERPs)

Memory for performed and interrupted actions was measured on source recognition and source recall tests in order to investigate output monitoring (i.e., memory for actions). Event-related potentials (ERPs) were recorded during the source recognition test to provide insight into the neural basis of output monitoring (OM). Source identification and recall of performed actions was greater than interrupted actions, thereby replicating the enactment effect. Examination of memory errors revealed that interrupted actions were more often mistaken as performed actions. The ERP data indicated that brain activity elicited by performed actions differed from interrupted and new actions. A clear difference in temporal onset of two ERP effects (i.e., a central-parietal and a frontal ERP difference) was observed, and it supports the previous hypothesis that two distinct processes support OM and source monitoring judgements. The pattern of frontal ERP differences suggested that interrupted actions prompted people to use more systematic decision processes overall to make OM judgements. Central-parietal ERP effects suggested that sensori-motor information was not recollected for interrupted actions—rather OM judgements were based on cognitive operations in this case.     

物体分类任务中线索效应的ERP研究

本实验采用ERP技术,对图片分类任务中的线索效应进行研究。实验任务为:图形形状判断、动物/非动物判断。靶刺激图片前呈现线索。线索分为有效线索、无效线索和中性线索。结果发现:(1)有效线索条件下对靶刺激的早期知觉再认得到易化——知觉加工成分波幅下降;(2)有效线索条件下,靶刺激中与任务相关的信息得到加工——任务相关的特异性成分增强。有效线索易化对靶刺激的知觉辨认,提取与线索提供背景相关的信息,促进行为反应。     

“Wanted!” The effects of reward on face recognition: electrophysiological correlates

The aim of the present study was to uncover the temporal dynamics of face recognition as a function of reward. Event-related potentials (ERPs) were recorded during the encoding and the subsequent old/new memory test in response to faces that could be associated with a monetary reward. The behavioral results showed that faces associated with reward at both encoding and retrieval were recognized better than the unrewarded ones. ERP responses highlighted that successful encoding predictive of subsequent memory was greater for faces associated with reward than for faces without reward-driven motivational learning. At retrieval, an early positive-going component was elicited for potentially rewarded faces on frontal regions, while the occipito-temporal N170 component showed priming effects as a function of reward. Later on, larger centro-parietal ERP components, related to recognition memory, were found selectively for reward-associated faces. Remarkably, electrophysiological responses varied in a graded manner, with the largest amplitude yielded by faces with double reward, followed by faces associated with reward only at encoding. Taken together, the present data show that the processing of outcome expectations affects face structural encoding and increases memory efficiency, yielding a robust and sustained modulation over frontal and temporal areas where reward and memory mechanisms operate in conjunction.     

任务转换中惯性激活对内隐记忆的影响：来自ERPs的证据

以往研究认为内隐记忆具有不受干扰影响的自动化加工特征,其证据主要来自于对内隐记忆编码过程的研究。最近已有多项研究发现,内隐记忆受提取过程中的干扰影响,但对这一现象的产生机制目前仍尚无定论。本研究根据任务转换相关理论,通过将go/no-go范式引入干扰任务,探讨提取过程中前置干扰对内隐记忆产生影响的内在机制。结果表明,前置的干扰任务产生惯性激活时,后续的内隐记忆任务会受到影响,即启动效应降低。对惯性激活进行抑制后,随后的内隐记忆则不受影响。并且,在内隐记忆相关的N400成分上得到了与行为数据一致的结果,即在no-go干扰下,获得的N400新旧效应,在go干扰下却未被发现。研究结果证明,提取干扰对内隐记忆的影响主要由干扰任务与内隐记忆任务对认知资源的竞争导致。     

The effects of direction similarity in visual working memory: Behavioural and event-related potential studies

Object similarity can improve visual working memory (VWM) performance in the change-detection task, but impair the recognition performance when it occurs at retrieval of VWM in the recognition task. The effect of direction similarity is an issue that has not been well resolved. Furthermore, electrophysiological evidence in support of the mechanisms that underlie the effects of similarity is still scarce. In the current study, we conducted three behavioural experiments to examine the effects of direction similarity on memory performance with regard to both the encoding and retrieval phases of VWM and one event-related potential (ERP) experiment to explore the neural signatures of direction similarity in VWM. Our behavioural studies indicated that direction similarity improved performance when it occurred at the encoding phase but impaired performance when it occurred at the retrieval phase. Moreover, the ERP experiment showed that the amplitude of the contralateral delay activity (CDA) increased with the increasing set size for similar but not dissimilar directions. In addition, the CDA amplitude for similar directions was lower than that for dissimilar directions at set size 2. Taken together, these findings suggest that direction similarity at encoding has a positive effect on VWM performance and at retrieval has a negative effect. Given that VWM capacity depends on information load and the number of objects, the positive effect of similarity may be attributed to reduced information load of memory objects.     

Electrophysiological correlates of processes supporting memory for faces

The retrieval processes supporting recognition memory for faces were investigated using event-related potentials (ERPs). The focus for analyses was ERP old/new effects, which are the differences between neural activities associated with correct judgments to old (studied) and new (unstudied) test stimuli. In two experiments it was possible to identify three old/new effects that behaved as neural indices of the process of recollection. In both experiments there was one old/new effect that behaved as an index of the process of familiarity. These outcomes are relevant to the ongoing debate about the functional significance of ERP old/new effects and the implications that scalp-recorded electrophysiological data have for theories of the processes supporting long-term memory judgments.     

Affective recognition memory processing and event-related brain potentials

Recognition memory was examined for visual affective stimuli using behavioral and event-related brain potential (ERP) measures. Images from the International Affective Picture System (IAPS) that varied systematically in arousal level (low, high) and valence direction (unpleasant, pleasant) were first viewed passively. Then, during a response phase, the original images were intermixed with an equal number of new images and presented, and participants were instructed to press a button to indicate whether each stimulus picture was previously viewed (target) or new (foil). Participants were more sensitive to unpleasant- than to pleasant-valence stimuli and were biased to respond to high-arousal unpleasant stimuli as targets, whether the stimuli were previously viewed or new. Response times (RTs) to target stimuli were systematically affected by valence, whereas RTs to foil stimuli were influenced by arousal level. ERP component amplitudes were generally larger for high than for low arousal levels. The P300 (late positive component) amplitude was largest for high-arousal unpleasant target images. These and other amplitude effects suggest that high-arousal unpleasant stimuli engage a privileged memory-processing route during stimulus processing. Theoretical relationships between affective and memory processes are discussed.     

ERP and behavioral evidence of individual differences in metaphor comprehension

In two experiments, we examined individual differences in metaphor processing. In Experiment 1, the subjects judged the literal truth of literal, metaphorical, and scrambled sentences. Overall, metaphors were more difficult to judge as false, in comparison with scrambled controls, suggesting that the metaphorical meaning was being processed automatically. However, there were individual differences in that high-IQ subjects showed more interference. These effects were reflected in ERP amplitude differences at the onset of N400 and after the response. In Experiment 2, the subjects completed IQ tests and a series of working memory tests and then rated and interpreted the same set of metaphors. The results showed that IQ was correlated with working memory capacity and that low-IQ subjects had similar ratings but poorer quality interpretations than did high-IQ subjects. The results were most consistent with a constraint satisfaction approach to metaphor comprehension.     

ERP correlates of target–distracter differentiation in repeated runs of a continuous recognition task with emotional and neutral faces

The emotional salience of faces has previously been shown to induce memory distortions in recognition memory tasks. This event-related potential (ERP) study used repeated runs of a continuous recognition task with emotional and neutral faces to investigate emotion-induced memory distortions. In the second and third runs, participants made more false alarms to distracters (repeated from previous runs). Emotion did not modulate the amount of errors, but the extent to which recollection was employed to maximise performance as reflected in the putative ERP correlate of recollection; the parietal old–new effect. Targets from all stimulus classes (positive, negative, neutral) were associated with parietal ERP memory effects, but this was also the case for correctly rejected negative distracters. This suggests that recollection was strategically used to correctly reject negative distracters (recall-to-reject). This finding is consistent with the view that facilitated recollection of negative stimuli may be used to decrease the susceptibility to memory errors induced by emotional salience.     

Electrophysiological correlates of exemplar-specific processes in implicit and explicit memory

The present ERP study investigated the retrieval of task-irrelevant exemplar-specific information under implicit and explicit memory conditions. Subjects completed either an indirect memory test (a natural/artificial judgment) or a direct recognition memory test. Both test groups were presented with new items, identical repetitions, and perceptually different but conceptually similar exemplars of previously seen study objects. Implicit and explicit memory retrieval elicited clearly dissociable ERP components that were differentially affected by exemplar changes from study to test. In the indirect test, identical repetitions, but not different exemplars, elicited a significant ERP repetition priming effect. In contrast, both types of repeated objects gave rise to a reliable old/new effect in the direct test. The results corroborate that implicit and explicit memory fall back on distinct cognitive representation and, more importantly, indicate that these representations differ in the type of stimulus information stored. Implicit retrieval entailed obligatory access to exemplar-specific perceptual information, despite its being task irrelevant. In contrast, explicit retrieval proved to be more flexible with conceptual and perceptual information accessed according to task demands.