Stop laughing! Humor perception with and without expressive suppression

The neurophysiological study of emotion regulation focused on the strategy of reappraisal—i.e., the cognitive reinterpretation of a stimulus. Reappraisal reduces emotional expression, the experience of both negative and positive feelings, and the amplitude of an event-related potential (ERP)—the late positive potential (LPP). In contrast, the strategy of expressive suppression (ES), being the inhibition of emotional expression, has been reported to reduce subjective feelings of positive, but not negative emotion, and has not yet been investigated with ERPs. We focused on the LPP to assess the correlates of ES in the context of humor perception. Twenty-two female participants rated sequences of humorous (H) and non-humorous (NH) pictures, while their zygomaticus muscle was recorded. A spontaneous (SP) condition, in which participants attended naturally to the pictures, resulted in higher ratings of funniness, increased smiling, and increased LPP amplitude for H compared to NH stimuli. An ES condition, in which participants suppressed their facial reactions, resulted in reduced smiling, without affecting subjective ratings. LPP amplitude did not differ between H and NH stimuli during ES, suggesting equal allocation of processing resources to both stimuli. These results suggest that, similarly to reappraisal, ES modifies the way the brain processes positive emotional stimuli.     

晚期正电位技术在垂体腺瘤病人情绪加工功能障碍评估中的应用

目的 探讨晚期正电位（LPP）在垂体腺瘤病人情绪加工功能障碍评估中的应用价值。方法 2018年6月2019年12月前瞻性收集26例垂体腺瘤和26例健康志愿者（对照组）,使用10-20国际标准化系统记录头皮中央、顶部脑电数据,头皮电阻降到5 kΩ以下,采样率为1 000 Hz,滤波带宽在0.05~200 Hz;从国际情感图片系统中选择45张图片,包括15幅正性刺激图像、15幅负性刺激图像和15幅中性刺激图像。结果 无论是垂体腺瘤病人,还是健康志愿者,正性刺激和中性刺激均可以诱发出显著的LPP成分;与中性刺激引起的LPP振幅相比,正性刺激诱发的两侧顶叶LPP振幅更大（P<0.05）。负性刺激情况下,对照组LPP振幅[（2.435±0.419）μV]显著大于垂体腺瘤组[（0.656±0.427）μV;P=0.005];正性刺激情况下,对照组LPP振幅[（1.450±0.316）μV]也显著大于垂体腺瘤组[（0.495±0.322）μV;P=0.040]。对照组右侧顶叶LPP振幅[（1.993±0.299）μV]显著大于垂体腺瘤组[（0.269±0.305）μV;P=0.001]。结论 垂体腺瘤病人存在情绪加工功能障碍,提示临床除了关注垂体腺瘤本身的治疗外,还要重视病人的情绪加工能力障碍。     

‘Ecstasy’ as a social drug: MDMA preferentially affects responses to emotional stimuli with social content

3,4-Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is used recreationally to improve mood and sociability, and has generated clinical interest as a possible adjunct to psychotherapy. One way that MDMA may produce positive ‘prosocial’ effects is by changing responses to emotional stimuli, especially stimuli with social content. Here, we examined for the first time how MDMA affects subjective responses to positive, negative and neutral emotional pictures with and without social content. We hypothesized that MDMA would dose-dependently increase reactivity to positive emotional stimuli and dampen reactivity to negative stimuli, and that these effects would be most pronounced for pictures with people in them. The data were obtained from two studies using similar designs with healthy occasional MDMA users (total N = 101). During each session, participants received MDMA (0, 0.75 and 1.5 mg/kg oral), and then rated their positive and negative responses to standardized positive, negative and neutral pictures with and without social content. MDMA increased positive ratings of positive social pictures, but reduced positive ratings of non-social positive pictures. We speculate this ‘socially selective’ effect contributes to the prosocial effects of MDMA by increasing the comparative value of social contact and closeness with others. This effect may also contribute to its attractiveness to recreational users.     

Motivated attention to cocaine and emotional cues in abstinent and current cocaine users--an ERP study

Event-related potentials (ERPs) are a direct measure of neural activity and are ideally suited to study the time-course of attentional engagement with emotional and drug-related stimuli in addiction. In particular, the late positive potential (LPP) appears to be enhanced following cocaine-related compared with neutral stimuli in human participants with cocaine use disorders (CUD). However, previous studies have not directly compared cocaine-related with emotional stimuli while examining potential differences between abstinent and current cocaine users. The present study examined ERPs in 55 CUD (27 abstinent and 28 current users) and 29 matched healthy controls while they passively viewed pleasant, unpleasant, neutral and cocaine-related pictures. To examine the time-course of attention to these stimuli, we analysed both an early and later window in the LPP as well as the early posterior negativity (EPN), established in assessing motivated attention. Cocaine pictures elicited increased electrocortical measures of motivated attention in ways similar to affectively pleasant and unpleasant pictures in all CUD, an effect that was no longer discernible during the late LPP window for the current users. This group also exhibited deficient processing of the other emotional stimuli (early LPP window - pleasant pictures; late LPP window - pleasant and unpleasant pictures). Results were unique to the LPP and not EPN. Taken together, results support a relatively early attention bias to cocaine stimuli in cocaine-addicted individuals, further suggesting that recent cocaine use decreases such attention bias during later stages of processing but at the expense of deficient processing of other emotional stimuli.     

Altered emotional information processing in borderline personality disorder: An electrophysiological study

Emotional dysregulation is one of the key symptoms of patients with borderline personality disorder (BPD). In the present study it is hypothesized that borderline patients display a cortical hyper-responsivity to emotional stimuli compared with a healthy control group. Further, we aimed to examine whether BPD patients were able to suppress stimuli with negative emotional valence as well as healthy control participants could. This is the first study addressing the electrophysiological processing of emotional stimuli in BPD. The electrophysiological response to emotional information was studied among 30 BPD patients and compared with the response in 30 normal controls using event-related potentials (ERPs). Participants were shown pictures selected from the International Affective Picture System with neutral, positive, and negative valence. After performing an attentional task, the participants were asked to perform a reappraisal task. The assignment was to consciously suppress emotions that might occur after viewing pictures with an unpleasant content. Borderline patients displayed larger late positive potentials (LPP) to pictures with an unpleasant valence as compared with the control group, indicating an enhanced elaborative processing of unpleasant stimuli. However, they did not differ on the reappraisal task. Borderline patients show an enhanced emotional cortical reactivity to unpleasant stimuli as compared with a control group. This suggests an emotional dysfunctioning in BPD patients. This feature might be an important focus in the treatment of BPD.     

Emotional picture processing in children: an ERP study

The late positive potential (LPP) reflects increased attention to emotional versus neutral stimuli in adults. To date, very few studies have examined the LPP in children, and whether it can be used to measure patterns of emotional processing that are related to dispositional mood characteristics, such as temperamental fear and anxiety. To examine this question,39 typically developing 5–7 year olds (M age in months = 75.27, SD = 5.83) passively viewed complex emotional and neutral pictures taken from the International Affective Picture System.Maternal report of temperamental fear and anxiety was obtained and fearful behavior during an emotional challenge was observed. As documented in adults, LPP amplitudes to pleasant and unpleasant stimuli were larger than to neutral stimuli, although some gender differences emerged. Larger LPP amplitude differences between unpleasant and neutral stimuli were associated with greater observed fear. The LPP as a measure of individual differences in emotional processing is discussed.     

Processing of unattended, simple negative pictures resists perceptual load

As researchers debate whether emotional pictures can be processed irrespective of spatial attention and perceptual load, negative and neutral pictures of simple figure-ground composition were shown at fixation and were surrounded by one, two, or three letters. When participants performed a picture discrimination task, there was evidence for motivated attention; that is, an early posterior negativity (EPN) and late positive potential (LPP) to negative versus neutral pictures. When participants performed a letter discrimination task, the EPN was unaffected whereas the LPP was reduced. Although performance decreased substantially with the number of letters (one to three), the LPP did not decrease further. Therefore, attention to simple, negative pictures at fixation seems to resist manipulations of perceptual load.     

The impact of verbal framing on brain activity evoked by emotional images

Emotional stimuli generally command more brain processing resources than non-emotional stimuli, but the magnitude of this effect is subject to voluntary control. Cognitive reappraisal represents one type of emotion regulation that can be voluntarily employed to modulate responses to emotional stimuli. Here, the late positive potential (LPP), a specific event-related brain potential (ERP) component, was measured in response to neutral, positive and negative images while participants performed an evaluative categorization task. One experimental group adopted a "negative frame" in which images were categorized as negative or not. The other adopted a "positive frame" in which the exact same images were categorized as positive or not. Behavioral performance confirmed compliance with random group assignment, and peak LPP amplitude to negative images was affected by group membership: brain responses to negative images were significantly reduced in the "positive frame" group. This suggests that adopting a more positive appraisal frame can modulate brain activity elicited by negative stimuli in the environment.     

Brain dynamics of visual attention during anticipation and encoding of threat- and safe-cues in spider-phobic individuals

This study systematically investigated the sensitivity of the phobic attention system by measuring event-related potentials (ERPs) in spider-phobic and non-phobic volunteers in a context where spider and neutral pictures were presented (phobic threat condition) and in contexts where no phobic but unpleasant and neutral or only neutral pictures were displayed (phobia-irrelevant conditions). In a between-group study, participants were assigned to phobia-irrelevant conditions either before or after the exposure to spider pictures (pre-exposure vs post-exposure participants). Additionally, each picture was preceded by a fixation cross presented in one of three different colors that were informative about the category of an upcoming picture. In the phobic threat condition, spider-phobic participants showed a larger P1 than controls for all pictures and signal cues. Moreover, individuals with spider phobia who were sensitized by the exposure to phobic stimuli (i.e. post-exposure participants) responded with an increased P1 also in phobia-irrelevant conditions. In contrast, no group differences between spider-phobic and non-phobic individuals were observed in the P1-amplitudes during viewing of phobia-irrelevant stimuli in the pre-exposure group. In addition, cues signaling neutral pictures elicited decreased stimulus-preceding negativity (SPN) compared with cues signaling emotional pictures. Moreover, emotional pictures and cues signaling emotional pictures evoked larger early posterior negativity (EPN) and late positive potential (LPP) than neutral stimuli. Spider phobics showed greater selective attention effects than controls for phobia-relevant pictures (increased EPN and LPP) and cues (increased LPP and SPN). Increased sensitization of the attention system observed in spider-phobic individuals might facilitate fear conditioning and promote generalization of fear playing an important role in the maintenance of anxiety disorders.     

Decomposing valence intensity effects in disgusting and fearful stimuli: an event-related potential study

We are sensitive to valence intensity in negative emotional stimuli, but not in positive emotional stimuli, a phenomenon known as the valence intensity effect. However, whether this valence intensity effect is processed similarly within different negative stimuli, e.g., fear-inducing and disgust-inducing, remains unclear. In the present study, we investigated whether the valence intensity effects for fearful and disgusting stimuli were perceived in a unique way by using event-related potentials (ERPs). Electroencephalogram was recorded from 22 participants as they performed a standard/deviant categorization task using extremely disgusting pictures, moderately disgusting pictures, extremely fearful pictures, moderately fearful pictures, and neutral pictures. The ERP analysis revealed that the extremely fearful stimuli elicited a larger amplitude N2 than moderately fearful stimuli, whereas the extremely disgusting stimuli elicited a smaller amplitude late positive component than moderately disgusting stimuli. This study is the first to provide evidence that fear and disgust may have different valence intensity effects, which was revealed at early attention allocation stages for fearful stimuli and at late emotional evaluation stages for disgusting stimuli.     

Cognitive and physiological dissociations in response to emotional pictures in patients with anorexia

Recent studies suggest that patients with anorexia may express dissociated cognitive and physiological reactivities to emotional stimuli. The present research aimed to compare subjective and autonomic responses to pleasant, unpleasant and neutral scenes during a categorization task and an activation rating task in anorexic (AN), alexithymic (AL), depressed (DEP) and control participants (CONT). The participants first categorized pictures according to their emotional valence, followed by a rating of their activation level, concomitant with the recording of skin conductance responses (SCRs). Main findings showed that the AN patients presented major difficulty in categorizing pictures, particularly neutral ones. Contrary to the AL participants, this difficulty did not induce significant increases of SCR amplitude in the AN patients. In the second task, the AN patients rated the intensity of activation of unpleasant pictures higher than the AL participants and that of pleasant ones higher than the AL and CONT participants. In addition, no significant linear correlation was observed between the intensity of activation ratings and SCR amplitude in the AN, AL or DEP participants contrarily to what was observed for control participants. This lack of relation suggests a non-specific disconnection between physiological and cognitive self-reported responses to emotional stimuli. Our results highlight a specific form of emotional processing in the AN patients distinct from that observed in alexithymia or depression and characterized by a dissociation between cognitive and physiological responses. This kind of disconnection could be associated with emotional regulation processes and may benefit the AN patients by lowering the psychological stress response.     

Lasting effects of cognitive emotion regulation: neural correlates of reinterpretation and distancing

Reinterpretation and distancing are two cognitive reappraisal tactics, used to regulate one’s emotions in response to emotion-eliciting stimuli or situations. Relatively less is known about their (differential) lasting effects on emotional responding and related neural correlates. This functional magnetic resonance imaging study investigated 85 healthy females, participating in a 2-day cognitive emotion regulation experiment. On the first day, participants were instructed to passively look at, reinterpret or distance from repeatedly presented aversive pictures. One week later, they were re-exposed to the same stimuli without regulation instruction, in order to assess lasting effects. The main outcome measures comprised ratings of negative feelings and blood-oxygen-level-dependent responses. Lasting effects for reinterpretation compared with looking at aversive pictures during passive re-exposure 1 week later were reflected in stronger activation of the left amygdala, the ventromedial prefrontal cortex (vmPFC) and reduced negative feelings. Neither distancing compared with looking at aversive pictures nor reinterpretation compared with distancing did result in significant effects during re-exposure. These findings indicate that reinterpretation leads to reduced negative feelings 1 week later, which might be mediated by inhibitory vmPFC activation or stronger positive emotions during re-exposure. However, the missing difference compared with distancing questions the specificity of the results and the mechanisms underlying these two cognitive reappraisal tactics.     

HIV-positive females show blunted neurophysiological responses in an emotion–attention dual task paradigm

ObjectiveAlthough HIV is associated with decreased emotional and cognitive functioning, the mechanisms through which affective changes can alter cognitive processes in HIV-infected individuals are unknown. We aimed to clarify this question through testing the extent to which emotionally negative stimuli prime attention to a subsequent infrequently occurring auditory tone in HIV+ compared to HIV− females.MethodsAttention to emotional compared to non-emotional pictures was measured via the LPP ERP. Subsequent attention was indexed through the N1 and late processing negativity ERP. We also assessed mood and cognitive functioning in both groups.ResultsIn HIV− females, emotionally negative pictures, compared to neutral pictures, resulted in an enhanced LPP to the pictures and an enhanced N1 to subsequent tones. The HIV+ group did not show a difference in the LPP measure between picture categories, and accordingly, did not show a priming effect to the subsequent infrequent tones.ConclusionsThe ERP findings, combined with neuropsychological deficits, suggest that HIV+ females show impairments in attention to emotionally-laden stimuli and that this impairment might be related to a loss of affective priming.SignificanceThis study is the first to provide physiological evidence that the LPP, a measure of attention to emotionally-charged visual stimuli, is reduced in HIV-infected individuals. These results set the stage for future work aimed at localizing brain activation to emotional stimuli in HIV+ individuals.     

Intact motivated attention in schizophrenia: evidence from event-related potentials

Emotionally significant stimuli typically capture attention (called motivated attention) even when they are irrelevant to tasks where attention is directed. Previous studies indicate that several components of emotional processing are intact in schizophrenia when subjects are instructed to attend to emotionally-evocative stimuli. However, few studies have examined whether emotional stimuli capture attention to a normal degree in people with schizophrenia when attention is directed elsewhere. The current event-related potential study examined motivated attention to task-irrelevant emotional stimuli in 35 stabilized outpatients and 26 healthy controls with a modified visual P300 oddball detection task. Participants viewed images of rare target and commonly occurring standard letter stimuli, as well as intermixed emotional (unpleasant, pleasant, neutral) pictures. Subjects were instructed to count the number of rare targets; the emotional valence of the picture stimuli was, therefore, task-irrelevant. We separately evaluated the Early Posterior Negativity (EPN) and Late Positive Potential (LPP) to emotional pictures and the P300 to target stimuli. Patients and controls showed similar patterns of EPN and LPP amplitude to the emotional stimuli, such that the EPN and LPP were larger for both pleasant and unpleasant versus neutral pictures. Although patients performed worse than controls on the target counting task, both groups showed comparable P300 differentiation between target versus non-target stimuli. Emotional stimuli captured attentional resources in people with schizophrenia even when the emotional stimuli were task-irrelevant, suggesting intact motivated attention at the level of early electrophysiological responding.     

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.     

Beautiful friendship: Social sharing of emotions improves subjective feelings and activates the neural reward circuitry

Humans have a strong tendency to affiliate with other people, especially in emotional situations. Here, we suggest that a critical mechanism underlying this tendency is that socially sharing emotional experiences is in itself perceived as hedonically positive and thereby contributes to the regulation of individual emotions. We investigated the effect of social sharing of emotions on subjective feelings and neural activity by having pairs of friends view emotional (negative and positive) and neutral pictures either alone or with the friend. While the two friends remained physically separated throughout the experiment—with one undergoing functional magnetic resonance imaging and the other performing the task in an adjacent room—they were made aware on a trial-by-trial basis whether they were seeing pictures simultaneously with their friend (shared) or alone (unshared). Ratings of subjective feelings were improved significantly when participants viewed emotional pictures together than alone, an effect that was accompanied by activity increase in ventral striatum and medial orbitofrontal cortex, two important components of the reward circuitry. Because these effects occurred without any communication or interaction between the friends, they point to an important proximate explanation for the basic human motivation to affiliate with others, particularly in emotional situations.     

Time course of emotion-related responding during distraction and reappraisal

Theoretical accounts of emotion regulation (ER) discriminate various cognitive strategies to voluntarily modify emotional states. Amongst these, attentional deployment (i.e. distraction) and cognitive change (i.e. reappraisal), have been shown to successfully down-regulate emotions. Neuroimaging studies found that both strategies differentially engage neural structures associated with selective attention, working memory and cognitive control. The aim of this study was to further delineate similarities and differences between the ER strategies reappraisal and distraction by investigating their temporal brain dynamics using event-related potentials (ERPs) and their patterns of facial expressive behavior. Twenty-one participants completed an ER experiment in which they had to either passively view positive, neutral and negative pictures, reinterpret them to down-regulate affective responses (reappraisal), or solve a concurrently presented mathematical equation (distraction). Results demonstrate the efficacy of both strategies in the subjective control of emotion, accompanied by reductions of facial expressive activity (Corrugator supercilii and Zygomaticus major). ERP results indicated that distraction, compared with reappraisal, yielded a stronger and earlier attenuation of the late positive potential (LPP) magnitude for negative pictures. For positive pictures, only distraction but not reappraisal had significant effect on LPP attenuation. The results support the process model of ER, separating subtypes of cognitive strategies based on their specific time course.     

Directed and motivated attention during processing of natural scenes

Abstract Visual attention can be voluntarily oriented to detect target stimuli in order to facilitate goal-directed behaviors. Other visual stimuli capture attention because of motivational significance. The aim of the present study was to investigate the relationship between directed and motivated attention using event-related potentials. Affectively engaging pictures were presented either as target stimuli or as nontargets in a categorization task. Results indicated that both task relevance and emotional significance modulated the late positive potential (LPP) over centro-parietal sensors. Effects of directed and motivated attention on the LPP were additive, with the largest centro-parietal positivity found for emotional pictures that were targets of directed attention, and the least for neutral pictures that were nontargets. Taken together, the data provide new information regarding the relationship between motivated and directed attention, and suggest that the LPP reflects the operation of attentional neural circuits that are utilized by both top-down and bottom-up processes.     

Neural correlates of positive and negative emotion regulation

The ability to cope adaptively with emotional events by volitionally altering one's emotional reactions is important for psychological and physical health as well as social interaction. Cognitive regulation of emotional responses to aversive events engages prefrontal regions that modulate activity in emotion-processing regions such as the amygdala. However, the neural correlates of the regulation of positive emotions remain largely unexplored. We used event-related functional magnetic resonance imaging to examine the neural correlates of cognitively increasing and decreasing emotional reactions to positive and negative stimuli. Participants viewed negative, positive, and neutral pictures while attempting to increase, decrease, or not alter their emotional reactions. Subjective reactions were assessed via on-line ratings. Consistent with previous studies, increasing negative and positive emotion engaged primarily left-lateralized prefrontal regions, whereas decreasing emotion activated bilateral prefrontal regions. Different activations unique to increasing versus decreasing emotion were observed for positive and negative stimuli: Unique increase-related activations were observed only for positive stimuli, whereas unique decrease-related activations were observed only for negative stimuli. Regulation also modulated activity in the amygdala, a key emotion-processing region. Regulation effects on amygdala activity were larger for positive than for negative stimuli, potentially reflecting a greater malleability of positive emotional reactions. Increasing and decreasing positive and negative emotion can thus increase and decrease subjective reactions and associated amygdala activity in line with regulatory goals, and is associated with different patterns of prefrontal activation as a function of emotional valence and regulatory goal.