Interdependent selves show face-induced facilitation of error processing: cultural neuroscience of self-threat

The fundamentally social nature of humans is revealed in their exquisitely high sensitivity to potentially negative evaluations held by others. At present, however, little is known about neurocortical correlates of the response to such social-evaluative threat. Here, we addressed this issue by showing that mere exposure to an image of a watching face is sufficient to automatically evoke a social-evaluative threat for those who are relatively high in interdependent self-construal. Both European American and Asian participants performed a flanker task while primed with a face (vs control) image. The relative increase of the error-related negativity (ERN) in the face (vs control) priming condition became more pronounced as a function of interdependent (vs independent) self-construal. Relative to European Americans, Asians were more interdependent and, as predicted, they showed a reliably stronger ERN in the face (vs control) priming condition. Our findings suggest that the ERN can serve as a robust empirical marker of self-threat that is closely modulated by socio-cultural variables.     

Motivated and controlled attention to emotion: Time-course of the late positive potential

ObjectiveThe present study examined the time-course of automatic and controlled modulation of the late positive potential (LPP) during emotional picture viewing.MethodsParticipants (N = 32) viewed neutral and unpleasant stimuli for 6000 ms; at 3000 ms, one of two tones signaled participants to attend either to a more or less arousing portion of the picture. The time-course of the LPP was examined both during the passive viewing and directed attention portions of the trial using the method proposed by Guthrie and Buchwald [Guthrie D, Buchwald JS. Significance testing of difference potentials. Psychophysiology 1991;28(2):240–4].ResultsDuring passive viewing, the LPP became reliably larger following the presentation of unpleasant pictures from 160 ms onward; the magnitude of the LPP became reliably smaller beginning 620 ms after participants were instructed to attend to the less arousing aspects of unpleasant pictures – and this difference was maintained throughout the duration of the trial.ConclusionsThe LPP reflects relatively automatic attention to emotional visual stimuli, but is also sensitive to manipulations of directed attention toward arousing versus neutral aspects of such stimuli.SignificanceThese results shed further light on the time-course of emotional and cognitive modulation of the LPP, and suggest that the LPP reflects the relatively rapid and dynamic allocation of increased attention to emotional stimuli.     

Online processing of moral transgressions: ERP evidence for spontaneous evaluation

Experimental studies using fictional moral dilemmas indicate that both automatic emotional processes and controlled cognitive processes contribute to moral judgments. However, not much is known about how people process socio-normative violations that are more common to their everyday life nor the time-course of these processes. Thus, we recorded participants’ electrical brain activity while they were reading vignettes that either contained morally acceptable vs unacceptable information or text materials that contained information which was either consistent or inconsistent with their general world knowledge. A first event-related brain potential (ERP) positivity peaking at ∼200 ms after critical word onset (P200) was larger when this word involved a socio-normative or knowledge-based violation. Subsequently, knowledge-inconsistent words triggered a larger centroparietal ERP negativity at ∼320 ms (N400), indicating an influence on meaning construction. In contrast, a larger ERP positivity (larger late positivity), which also started at ∼320 ms after critical word onset, was elicited by morally unacceptable compared with acceptable words. We take this ERP positivity to reflect an implicit evaluative (good–bad) categorization process that is engaged during the online processing of moral transgressions.     

Cultures differ in the ability to enhance affective neural responses

The present study (N = 55) used an event-related potential paradigm to investigate whether cultures differ in the ability to upregulate affective responses. Using stimuli selected from the International Affective Picture System, we found that European-Americans (N = 29) enhanced central-parietal late positive potential (LPP) (400–800 ms post-stimulus) responses to affective stimuli when instructed to do so, whereas East Asians (N = 26) did not. We observed cultural differences in the ability to enhance central-parietal LPP responses for both positively and negativelyvalenced stimuli, and the ability to enhance these two types of responses was positively correlated for Americans but negatively for East Asians. These results are consistent with the notion that cultural variations in norms and values regarding affective expression and experiences shape how the brain regulates emotions.     

ERP dynamics underlying successful directed forgetting of neutral but not negative pictures

Subjective experience suggests that negatively arousing memories are harder to control than neutral ones. Here, we investigate this issue in an item-cued directed forgetting experiment. Electroencephalogram event-related potentials (ERPs) were recorded as participants viewed un-arousing neutral and highly arousing negative photographs, each followed by a cue to remember or forget it. Directed forgetting, that is reduced recognition of ‘to-be-forgotten’ items, occurred for neutral but not negative pictures. ERPs revealed three underlying effects: first, during picture viewing a late parietal positive potential (LPP) was more pronounced for negative than for neutral pictures. Second, ‘remember’ cues were associated with larger LPPs than ‘forget’ cues. Third, an enhanced frontal positivity appeared for ‘forget’ cues. This frontal positivity was generated in right dorso-lateral prefrontal regions following neutral pictures and in medial frontal cortex following negative pictures. LPP magnitude when viewing negative pictures was correlated with reduced directed forgetting, whereas both the enhanced frontal positivity for forget cues and the larger parietal positivity for remember cues predicted more directed forgetting. This study indicates that both processes of selective rehearsal (parietal positivities) and frontally controlled inhibition contribute to successful directed forgetting. However, due to their deeper incidental processing, highly arousing negative pictures are exempt from directed forgetting.     

Event-related brain potential correlates of emotional face processing

Results from recent event-related brain potential (ERP) studies investigating brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical brain circuits.     

Suppression of aversive memories associates with changes in early and late stages of neurocognitive processing

Unwanted memories, such as emotionally negative, can be intentionally suppressed through voluntary control in humans. Memory suppression is thought to be mediated by the interplay of a chain of neurocognitive processes. However, empirical data in support of this notion is lacking. Using high-temporal resolution event-related potential (ERP) technique, we investigated the time course of ERPs associated with suppression of negative and neutral memories in a Think/No-Think paradigm in young, healthy participants. Results showed that participants had greater difficulty in suppressing emotionally negative memories than neutral ones. ERPs and source analyses demonstrated that memory suppression processing for negative and neutral memories were generally associated with changes during early components of a time window of 70-260ms, such as P1 and N2, mainly at the right inferior frontal gyrus and occipital lobe; suppression of aversive memories was associated with two major late ERP components between 380 and 800ms, with significantly smaller later negativity (LN) but larger late parietal positivity (LPP), primarily at the right medial and superior frontal gyri. These results suggest that differences in early components may reflect early stages of suppression processing including visual awareness, attention reallocation, and executive processing. Differences in late components between suppression of aversive and neutral memories may reflect a process of down-regulating conscious recollection of memory representations supported by prefrontal and parietal networks. A less effective control of this process, as evidenced by smaller LN and larger LPP, may explain the fact that emotionally negative memories were harder to be suppressed. Altogether, these findings suggest that suppression of aversive memories requires down-regulation of late conscious recollection, which can be dissociated from early visual and attention processing in memory suppression.     

Culture-related differences in default network activity during visuo-spatial judgments

Studies on culture-related differences in cognition have shown that Westerners attend more to object-related information, whereas East Asians attend more to contextual information. Neural correlates of these different culture-related visual processing styles have been reported in the ventral-visual and fronto-parietal regions. We conducted an fMRI study of East Asians and Westerners on a visuospatial judgment task that involved relative, contextual judgments, which are typically more challenging for Westerners. Participants judged the relative distances between a dot and a line in visual stimuli during task blocks and alternated finger presses during control blocks. Behaviorally, East Asians responded faster than Westerners, reflecting greater ease of the task for East Asians. In response to the greater task difficulty, Westerners showed greater neural engagement compared to East Asians in frontal, parietal, and occipital areas. Moreover, Westerners also showed greater suppression of the default network—a brain network that is suppressed under condition of high cognitive challenge. This study demonstrates for the first time that cultural differences in visual attention during a cognitive task are manifested both by differences in activation in fronto-parietal regions as well as suppression in default regions.     

An ERP study on the time course of emotional face processing

Using event-related brain potentials (ERPs), we investigated the time course of facial expression processing in human subjects watching photographs of fearful and neutral faces. Upright fearful faces elicited a frontocentral positivity within 120 ms after stimulus presentation, which was followed by a broadly distributed sustained positivity beyond 250 ms post-stimulus. Emotional expression effects were delayed and attenuated when faces were inverted. In contrast, the face-specific N170 component was completely unaffected by facial expression. We conclude that emotional expression analysis and the structural encoding of faces are parallel processes. Early emotional ERP modulations may reflect the rapid activation of prefrontal areas involved in the analysis of facial expression.     

No fear,no panic: probing negation as a means for emotion regulation

This electroencephalographic study investigated if negating one’s emotion results in paradoxical effects or leads to effective emotional downregulation. Healthy participants were asked to downregulate their emotions to happy and fearful faces by using negated emotional cue words (e.g. no fun, no fear). Cue words were congruent with the emotion depicted in the face and presented prior to each face. Stimuli were presented in blocks of happy and fearful faces. Blocks of passive stimulus viewing served as control condition. Active regulation reduced amplitudes of early event-related brain potentials (early posterior negativity, but not N170) and the late positive potential for fearful faces. A fronto-central negativity peaking at about 250 ms after target face onset showed larger amplitude modulations during downregulation of fearful and happy faces. Behaviorally, negating was more associated with reappraisal than with suppression. Our results suggest that in an emotional context, negation processing could be quite effective for emotional downregulation but that its effects depend on the type of the negated emotion (pleasant vs unpleasant). Results are discussed in the context of dual process models of cognition and emotion regulation.     

Trust at first sight: evidence from ERPs

We used event-related potentials (ERPs) to tap the temporal dynamics of first impressions based on face appearance. Participants were asked to evaluate briefly presented faces for trustworthiness and political choice. Behaviorally, participants were better at discriminating faces that were pre-rated as untrustworthy. The ERP results showed that the P100 component was enhanced for untrustworthy faces, consistently with the view that signals of potential threat are given precedence in neural processing. The enhanced ERP responses to untrustworthy faces persisted throughout the processing sequence and the amplitude of early posterior negativity (EPN), and subsequent late positive potential (LPP) was increased with respect to trustworthy faces which, in contrast, elicited an enhanced positivity around 150 ms on frontal sites. These ERP patterns were found specifically for the trustworthiness evaluation and not for the political decision task. Political decision yielded an increase in the N170 amplitude, reflecting a more demanding and taxing structural encoding. Similar ERP responses, as previously reported in the literature for facial expressions processing, were found throughout the entire time course specifically elicited by faces explicitly judged as untrustworthy. One possibility might be that evolution has provided the brain with a ‘special toolkit’ for trust evaluation that is fast and triggers ERPs related to emotional processing.     

The role of the right parietal cortex in sound localization: a chronometric single pulse transcranial magnetic stimulation study

Auditory spatial functions, including the ability to discriminate between the positions of nearby sound sources, are subserved by a large temporo-parieto-frontal network. With the aim of determining whether and when the parietal contribution is critical for auditory spatial discrimination, we applied single pulse transcranial magnetic stimulation on the right parietal cortex 20, 80, 90 and 150 ms post-stimulus onset while participants completed a two-alternative forced choice auditory spatial discrimination task in the left or right hemispace. Our results reveal that transient TMS disruption of right parietal activity impairs spatial discrimination when applied at 20 ms post-stimulus onset for sounds presented in the left (controlateral) hemispace and at 80 ms for sounds presented in the right hemispace. We interpret our finding in terms of a critical role for controlateral temporo-parietal cortices over initial stages of the building-up of auditory spatial representation and for a right hemispheric specialization in integrating the whole auditory space over subsequent, higher-order processing stages.     

Are there sex differences in ERPs related to processing empathy-evoking pictures?

ObjectiveThis study aimed to investigate sex differences in the temporal dynamics of experiencing empathy by using electrophysiological measurements.MethodsTwenty-five females and 27 males viewed 414 pictures of the International affective picture system varying in emotional valence (positive, negative and neutral) and presence of humans (human and scenes). EEG event related potentials (ERPs) were obtained and correlations were computed with self-reported empathy.ResultsCompared to males, females showed increased anterior N2 and parietal LPP amplitudes to humans contrasted with scenes (independent of emotional valence) and to negative contrasted with neutral emotions (independent of human presence). Independent of sex the N1 and anterior N2 were specifically increased for positive human emotions and the parietal LPP for negative human emotions. Across sexes, the N2 and LPP human emotion effects and LPP human effects were associated with self-reported affective empathy, but not with cognitive empathy.ConclusionsThis study provides electrophysiological evidence that women prioritize the processing of socially relevant and negative emotional information, but that women did not show enhanced brain potentials to pictures with positive or negative emotions in humans.     

Age-related differences in event-related potentials for early visual processing of emotional faces

With advancing age, processing resources are shifted away from negative emotional stimuli and toward positive ones. Here, we explored this ‘positivity effect’ using event-related potentials (ERPs). Participants identified the presence or absence of a visual probe that appeared over photographs of emotional faces. The ERPs elicited by the onsets of angry, sad, happy and neutral faces were recorded. We examined the frontocentral emotional positivity (FcEP), which is defined as a positive deflection in the waveforms elicited by emotional expressions relative to neutral faces early on in the time course of the ERP. The FcEP is thought to reflect enhanced early processing of emotional expressions. The results show that within the first 130 ms young adults show an FcEP to negative emotional expressions, whereas older adults show an FcEP to positive emotional expressions. These findings provide additional evidence that the age-related positivity effect in emotion processing can be traced to automatic processes that are evident very early in the processing of emotional facial expressions.     

Selective visual attention to emotional words: Early parallel frontal and visual activations followed by interactive effects in visual cortex

Human brains spontaneously differentiate between various emotional and neutral stimuli, including written words whose emotional quality is symbolic. In the electroencephalogram (EEG), emotional–neutral processing differences are typically reflected in the early posterior negativity (EPN, 200–300 ms) and the late positive potential (LPP, 400–700 ms). These components are also enlarged by task‐driven visual attention, supporting the assumption that emotional content naturally drives attention. Still, the spatio‐temporal dynamics of interactions between emotional stimulus content and task‐driven attention remain to be specified. Here, we examine this issue in visual word processing. Participants attended to negative, neutral, or positive nouns while high‐density EEG was recorded. Emotional content and top‐down attention both amplified the EPN component in parallel. On the LPP, by contrast, emotion and attention interacted: Explicit attention to emotional words led to a substantially larger amplitude increase than did explicit attention to neutral words. Source analysis revealed early parallel effects of emotion and attention in bilateral visual cortex and a later interaction of both in right visual cortex. Distinct effects of attention were found in inferior, middle and superior frontal, paracentral, and parietal areas, as well as in the anterior cingulate cortex (ACC). Results specify separate and shared mechanisms of emotion and attention at distinct processing stages. Hum Brain Mapp 37:3575–3587, 2016. © 2016 Wiley Periodicals, Inc .     

Self‐initiated learning reveals memory performance and electrophysiological differences between younger,older and older adults with relative memory impairment

Older adults display difficulties in encoding and retrieval of information, resulting in poorer memory. This may be due to an inability of older adults to engage elaborative encoding strategies during learning. This study examined behavioural and electrophysiological effects of explicit cues to self‐initiate learning during encoding and subsequent recognition of words in younger adults (YA), older control adults (OA) and older adults with relative memory impairment (OD). The task was a variation of the old/new paradigm, some study items were preceded by a cue to learn the word (L) while others by a do not learn cue (X). Behaviourally, YA outperformed OA and OD on the recognition task, with no significant difference between OA and OD. Event‐related potentials at encoding revealed enhanced early visual processing (70–140 ms) for L‐ versus X‐words in young and old. Only YA exhibited a greater late posterior positivity (LPP; 200–500 ms) for all words during encoding perhaps reflecting superior encoding strategy. During recognition, only YA differentiated L‐ versus X‐words with enhanced frontal P200 (150–250 ms) suggesting impaired early word selection for retrieval in older groups; however, OD had enhanced P200 activity compared to OA during L‐word retrieval. The LPP (250–500 ms) was reduced in amplitude for L‐words compared to both X‐ and new words. However, YA showed greater LPP amplitude for all words compared to OA. For older groups, we observed reduced left parietal hemispheric asymmetry apparent in YA during encoding and recognition, especially for OD. Findings are interpreted in the light of models of compensation and dedifferentiation associated with age‐related changes in memory function.     

Neural correlates of affective stimulus evaluation: a case-by-case analysis

A recent study provided first evidence that neural correlates of affective stimulus evaluation, that is, the early posterior negativity (EPN) and late positive potential (LPP), can be assessed at the individual case level. Expanding the case-by-case approach, the main aim of the present study was to explore the process of affective stimulus evaluation within the individual participant with respect to multiple emotional stimulus classes. Toward this end, each participant viewed separate blocks of low- and high-arousing pictures from behavior systems of predator fear, disease avoidance and sexual reproduction. Thirteen out of 16 participants showed larger EPN and LPP amplitudes for higher- than lower-arousing stimuli for all three behavior systems. Furthermore, rather than indicating a general lack of emotional modulation, cases of non-significant EPN (N = 3) and LPP (N = 2) tests in individual participants appeared to be specific to a single emotion category. Overall, assessing the emotional modulation of the EPN and LPP across multiple behavior systems strengthens the case-by-case approach regarding an effect that is ‘common to all’ as well as by differentiating non-significant effects within individuals in terms of a content-specific or general phenomenon. Implications for revealing a general principle of emotion functioning and biomarker development are discussed.     

Neural correlates of recognition memory for emotional faces and scenes

We examined the influence of emotional valence and type of item to be remembered on brain activity during recognition, using faces and scenes. We used multivariate analyses of event-related fMRI data to identify whole-brain patterns, or networks of activity. Participants demonstrated better recognition for scenes vs faces and for negative vs neutral and positive items. Activity was increased in extrastriate cortex and inferior frontal gyri for emotional scenes, relative to neutral scenes and all face types. Increased activity in these regions also was seen for negative faces relative to positive faces. Correct recognition of negative faces and scenes (hits vs correct rejections) was associated with increased activity in amygdala, hippocampus, extrastriate, frontal and parietal cortices. Activity specific to correctly recognized emotional faces, but not scenes, was found in sensorimotor areas and rostral prefrontal cortex. These results suggest that emotional valence and type of visual stimulus both modulate brain activity at recognition, and influence multiple networks mediating visual, memory and emotion processing. The contextual information in emotional scenes may facilitate memory via additional visual processing, whereas memory for emotional faces may rely more on cognitive control mediated by rostrolateral prefrontal regions.     

Processing of facial expressions of same-race and other-race faces: distinct and shared neural underpinnings

People understand others’ emotions quickly from their facial expressions. However, facial expressions of ingroup and outgroup members may signal different social information and thus be mediated by distinct neural activities. We investigated whether there are distinct neuronal responses to fearful and happy expressions of same-race (SR) and other-race (OR) faces. We recorded electroencephalogram from Chinese adults when viewing an adaptor face (with fearful/neutral expressions in Experiment 1 but happy/neutral expressions in Experiment 2) and a target face (with fearful expressions in Experiment 1 but happy expressions in Experiment 2) presented in rapid succession. We found that both fearful and happy (vs neutral) adaptor faces increased the amplitude of a frontocentral positivity (P2). However, a fearful but not happy (vs neutral) adaptor face decreased the P2 amplitudes to target faces, and this repetition suppression (RS) effect occurred when adaptor and target faces were of the same race but not when of different races. RS was observed on two late parietal/central positive activities to fearful/happy target faces, which, however, occurred regardless of whether adaptor and target faces were of the same or different races. Our findings suggest that early affective processing of fearful expressions may engage distinct neural activities for SR and OR faces.     

An ERP study of the temporal course of the Stroop color-word interference effect

The electrophysiological correlates of the Stroop color-word interference effect were studied in eight healthy subjects using high-density Event-Related Potentials (ERPs). Three response modalities were compared: Overt Verbal, Covert Verbal, and Manual. Both Overt Verbal and Manual versions of the Stroop yielded robust Stroop color-word interference as indexed by longer RT for incongruent than congruent color words. The Incongruent vs Congruent ERP difference wave presented two effects. A first effect was a medial dorsal negativity between 350-500 ms post-stimulus (peak at 410 ms). This effect had a significantly different scalp distribution in the Verbal and Manual Stroop versions, with an anterior-medial focus for overt or covert speech, and a broader medial-dorsal distribution for the manual task. Dipole source analysis suggested two independent generators in anterior cingulate cortex. Later on in time, a prolonged positivity developed between 500-800 ms post-stimulus over left superior temporo-parietal scalp. This effect was present for all the three response modalities. A possible interpretation of these results is that Stroop color-word interference first activates anterior cingulate cortex (350-500 ms post-stimulus), followed by activation of the left temporo-parietal cortex, possibly related to the need of additional processing of word meaning.