On the roles of distinctiveness and semantic expectancies in episodic encoding of emotional words

We examined the factors that contribute to enhanced recall for emotionally arousing words by analyzing behavioral performance, the P300 as an index of distinctiveness, and the N400 as an index of semantic expectancy violation in a modified Von Restorff paradigm. While their EEG was recorded, participants studied three list types (1) neutral words including one emotionally arousing isolate (either positive or negative), (2) arousing, negative words including one neutral isolate, or (3) arousing, positive words including one neutral isolate. Immediately after each list, free recall was tested. Negative, but not positive, words exhibited enhanced recall when presented as isolates in lists of neutral words and elicited a larger P300 for subsequently recalled than not‐recalled words. This suggests that arousing, negative words stand out and that their distinctiveness contributes to their superior recall. Positive valence had an enhancing effect on recall only when the list contained mostly other positive words. Neutral isolates placed in either positive or negative lists elicited an N400, suggesting that semantic expectations developed in emotional word lists regardless of valence. However, semantic relatedness appeared to more strongly contribute to recall for positive than negative words. Our results suggest that distinctiveness and semantic relatedness contribute to episodic encoding of arousing words, but the impact of each factor depends on both a word's valence and its context.     

Evidence for implicit self-positivity bias: an event-related brain potential study

We investigated the processing of self-related information under the prime paradigm using event-related potentials (ERPs) to provide evidence for implicit self-positivity bias in Chinese individuals. Reaction times and ERPs were recorded when participants made positive/negative emotional judgments to personality-trait adjectives about themselves or others. Faster responses occurred to self-related positive adjectives and other-related negative adjectives, indicating implicit self-positivity bias at the behavioral level. ERPs showed an interaction between prime and emotion at the P300 amplitude, with larger P300 amplitudes for words within the self-positivity bias, indicating that self-related information occupied more attentional resources. Larger N400 amplitudes elicited by words that were inconsistent with the self-positivity bias, suggesting that accessing non-self-relevant information is more difficult than self-relevant information. Thus, P300 and N400 could be used as neuro-indexes of the implicit self-positivity bias.     

Attentional bias modulation by reappraisal in patients with generalized anxiety disorder: an event-related potential study

Affective states influence subsequent attention allocation. We evaluated emotional negativity bias modulation by reappraisal in patients with generalized anxiety disorder (GAD) relative to normal controls. Event-related potential (ERP) recordings were obtained, and changes in P200 and P300 amplitudes in response to negative or neutral words were noted after decreasing negative emotion or establishing a neutral condition. We found that in GAD patients only, the mean P200 amplitude after negative word presentation was much higher than after the presentation of neutral words. In normal controls, after downregulation of negative emotion, the mean P300 amplitude in response to negative words was much lower than after neutral words, and this was significant in both the left and right regions. In GAD patients, the negative bias remained prominent and was not affected by reappraisal at the early stage. Reappraisal was observed to have a lateralized effect at the late stage.     

Event-related beta oscillations are affected by emotional eliciting stimuli

According to previous results, negative emotional facial expressions elicit oscillatory beta responses. The present study analyzes event-related beta oscillations upon presentation of International Affective Picture System (IAPS) and aims to show whether behavior of beta in response to negative IAPS pictures also have similar dynamics. IAPS pictures (unpleasant, pleasant, and neutral) were presented as a block and random passive viewing to 14 healthy subjects (8 male). Only with pictures with similar luminance level were selected as stimuli. Event-Related Potentials (ERPs) were recorded from 30 different scalp locations, and adaptive digital filtering was used for analysis in different frequency windows. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta responses (15–30 Hz) in the 0 and 300 ms time window. Beta responses were significantly higher for unpleasant pictures than for pleasant and neutral pictures (average 50%). Beta responses were significantly higher for unpleasant than for pleasant pictures over frontal, central and parietal electrode sides (p < 0.05). Furthermore, beta responses were significantly higher for unpleasant than for neutral pictures over parietal and occipital electrodes (p < 0.04). In addition, the pleasant pictures elicited higher beta responses than neutral pictures over occipital electrode sites (p < 0.04). The results of the present study indicate that negative emotions are related to increased beta responses in humans, independent of stimulus types (facial expression or IAPS pictures). Accordingly, beta responses to negative emotions are possibly a common phenomenon. The standardization of luminance in pictures may reduce divergences between results from different laboratories.     

Electrophysiological evidence of early processing deficits in alexithymia

Alexithymia describes difficulties to identify and describe one's emotions. Previous research focused on difficulties associated with the later processing stages of appraisal in alexithymia. We tested whether early processing deficits are apparent in alexithymic persons and whether these abnormalities contribute to later processing difficulties. 20 participants were selected and identified as either having high (HDA) or low (LDA) degrees of alexithymia. IAPS pictures were presented while EEG was recorded. For HDA subjects processing of emotional pictures was accompanied by reduced P1 amplitudes most pronounced for pleasant and neutral pictures. In response to unpleasant pictures the P3 amplitudes were reduced. These amplitude modulations were predicted only by one alexithymia facet. P1 amplitudes systematically covaried with P3 amplitudes supporting the assumption that deficits in early emotional processing contribute to later processing deficits.     

Event related potentials to emotional adjectives during reading

We investigated to what extent emotional connotation influences cortical potentials during reading. To this end, event-related potentials (ERPs) were recorded during reading of high arousal pleasant and unpleasant and low arousal neutral adjectives that were presented at rates of 1 Hz and 3 Hz. Enhanced processing of both pleasant and unpleasant emotional compared to neutral adjectives was first reflected in an amplified early posterior negativity (EPN) starting from 200 ms after word onset. Later potentials (>300 ms), as analyzed in the slower 1 Hz condition, revealed facilitated processing selectively for pleasant adjectives that were associated with a reduced N400 and an enhanced late positive potential (LPP). Pleasant adjectives were also better remembered in an incidental memory test. Thus, emotionally relevant adjectives are processed spontaneously and selectively. Initially, emotional arousal drives attention capture (EPN). Healthy subjects may have a natural bias toward pleasant information facilitating late ERPs (N400, LPP) to pleasant adjectives as well as their superior recall.     

Affective modulation of brain potentials to painful and nonpainful stimuli

In accordance with the emotional priming hypothesis, emotions seem to modulate pain perception and pain tolerance thresholds. To further evaluate this association, event-related brain potentials (ERPs) elicited by painful and nonpainful electrical stimuli during processing of positive, neutral, and negative valenced pictures were recorded from 30 healthy volunteers. Valence of pictures affected pain ratings and the N150 elicited by painful stimuli, with lowest amplitudes for positive pictures and highest amplitudes for negative pictures. The P260 elicited by painful and nonpainful stimuli was modulated by arousal with reduced amplitudes with arousing (positive or negative) compared to neutral pictures. N150 amplitudes varying with picture valence seem to reflect an affective modulation of pain perception whereas P260 amplitudes varying with picture arousal rather reflect non-pain-specific attentional processes.     

Latent inhibition mediates N1 attenuation to repeating sounds

Sound repetition typically reduces auditory N1 amplitudes, more so at higher rates. This has been attributed to refractoriness of N1 generators. However, evidence that N1 attenuation is delayed 300-400 ms after the first occurrence of a repeated sound suggests an alternative process, such as inhibition, that requires 300-400 ms to become fully operational. We examined the N1 to trains of fixed-interval (100, 200, 300, 400 ms) tones for evidence of effects predicted by models of refractoriness and of latent inhibition. Regardless of interval, latency of the eliciting tone from train onset determined N1 amplitudes during the first 400 ms of the train, which decreased in this window. The results show that N1 attenuation cannot be due simply to refractoriness, which would elicit the smallest N1 to the second tone. An inhibitory neural circuit can account for these and previous results, and may be important to auditory perceptual processing.     

Categorization of unilaterally presented emotional words: an ERP analysis

This study is intended to clarify the functional role of different ERP components as indicators of the processing of emotions. The effect of emotional connotation of words on hemispheric lateralization is also explored. Visual ERPs were recorded to unilaterally presented positive, negative, and neutral words that should be categorized according to their emotional connotation. The P2 amplitude was larger to positive than to negative words whereas P3 amplitude was larger to positive words compared with neutral ones. The slow positive wave (SPW) was influenced by words emotionality at anterior and posterior sites differently. The amplitude of the N1 component was larger in the left hemisphere to contralaterally presented words. The P2 and P3 components were larger over the left hemisphere whereas the N3 and N4 components were larger over the right hemisphere to ipsilateral stimulation. The results support our hypotheses on the functional role of positive ERP components in the processing of an affective words connotation: the P2 wave reflects a general evaluation of emotional significance, the P3 a task-related decision, and the SPW an additional decision control in the context of the emotional experience of an individual. Neither the "right hemisphere hypothesis" nor "valence hypothesis" on lateralization of the processing of emotions were confirmed. Each hemisphere seems to exert its effect on emotion through specific hemispheric resources that are unequally allocated along the different stages of task processing and may cause alternation of hemispheric dominance.     

Neural response to sustained affective visual stimulation using an indirect task

Event-related potentials were recorded from 30 subjects using sustained stimulation and an indirect task, two strategies which facilitate affective responses that are complete and free of cognitive interference. Stimuli were of three types: pleasant, unpleasant and neutral. A three-phase pattern was found. The first phase, an amplitude increase in response to negative stimuli higher than to neutral and pleasant stimuli, was produced at 160 ms after stimulus onset, the prefrontal cortex being the origin of this phase. The second phase, characterized by maximal amplitudes in response to positive stimuli, was produced at 400 ms, originating in the visual cortex. Finally, the third phase, another amplitude increase in response to negative stimuli, was produced at 680 ms, and its source was located in the left precentral gyrus. Present data show that the cortical response to sustained emotional visual stimulation presented within indirect tasks provides information on attention-, motivation- and motor-related biases that complement information obtained under other experimental conditions.     

Interoceptive sensitivity and emotion processing: an EEG study.

Theories of emotion consider the self-perception of visceral activity to play an important role in emotion. This study examined the relationship between interoceptive sensitivity and both the subjective emotional experience and the processing of emotional pictures. According to their results in a heartbeat detection task subjects were classified as good (N = 17) or poor (N = 20) heartbeat perceivers. Event-related potentials were recorded while subjects viewed pleasant, neutral and unpleasant pictures and SAM ratings were examined. Good heartbeat perceivers showed significantly greater P300 and slow wave amplitudes for emotional pictures at antero-inferior, medial and posterior electrode sites and experienced a greater arousal for emotional pictures compared to poor heartbeat perceivers. The heartbeat perception score correlated significantly positive both with emotional P300 and slow wave amplitudes as well as with the arousal ratings for emotional pictures. The results indicate that there is a significant and strong association between interoceptive sensitivity and the intensity of emotional experience as well as the central processing of emotional stimuli.     

Time course of automatic emotion regulation during a facial Go/Nogo task

Neuroimaging research has determined that the neural correlates of automatic emotion regulation (AER) include the anterior cingulate cortex. However, the corresponding time course remains unknown. In the current study, we collected event-related potentials (ERPs) from 20 healthy volunteers during a judgment of the gender of emotional faces in a cued Go/Nogo task. The results indicate that Go-N2 amplitudes and latencies following positive and negative faces decreased more than those following neutral faces; Nogo-N2 amplitudes and latencies did not vary with valence. Moreover, positive and negative faces prompted higher P3 amplitudes and shorter P3 latencies than neutral faces in both Go and Nogo trials. These observations suggest that in the executive processes, Go-N2 reflects top-down attention toward emotions, while Go-P3 reflects only motivated attention; in the inhibitory processes, Nogo-N2 reflects cognitive conflict monitoring, while Nogo-P3 overlaps with the automatic response inhibition of emotions. These observations imply that AER can modulate early ERP components, and both Go-N2 and Nogo-P3 can be used as electrophysiological indices of AER.     

Cognitive Reappraisal in Preschoolers: Neuropsychological Evidence of Emotion Regulation From an ERP Study

Late positive potential (LPP) is associated with the magnitude and intensity of emotional reactivity. Studies have linked the adoption of cognitive reappraisal to the reduction of LPP amplitude in adults and school-age children but not in preschoolers. It may be due to preschoolers’ difficulty in understanding and remembering given interpretations. We examined changes in LPP amplitudes following simplified interpretations of unpleasant pictures in 20 preschoolers (48–71 months). Results demonstrated that LPP amplitudes, following neutral interpretations, were lower as compared to negative interpretations, suggesting that preschoolers as young as four have developed the ability to use cognitive reappraisal strategies following instructions.     

Early emotion word processing: evidence from event-related potentials

Behavioral and electrophysiological responses were monitored to 80 controlled sets of emotionally positive, negative, and neutral words presented randomly in a lexical decision paradigm. Half of the words were low frequency and half were high frequency. Behavioral results showed significant effects of frequency and emotion as well as an interaction. Prior research has demonstrated sensitivity to lexical processing in the N1 component of the event-related brain potential (ERP). In this study, the N1 (135-180 ms) showed a significant emotion by frequency interaction. The P1 window (80-120 ms) preceding the N1 as well as post-N1 time windows, including the Early Posterior Negativity (200-300 ms) and P300 (300-450 ms), were examined. The ERP data suggest an early identification of the emotional tone of words leading to differential processing. Specifically, high frequency negative words seem to attract additional cognitive resources. The overall pattern of results is consistent with a time line of word recognition in which semantic analysis, including the evaluation of emotional quality, occurs at an early, lexical stage of processing.     

Adequate Versus Inadequate Response to Reading Intervention: An Event-Related Potentials Assessment

Three visual event-related potential components to the second of two sequentially presented words that rhymed or not discriminated children who improved (AR) from those who failed following (IR) reading intervention. Right hemisphere P100 amplitudes discriminated Typically Developing (TD) children from AR children but IR from AR children over left hemisphere sites. N200 amplitudes across hemispheres discriminated TD from IR children and AR from IR children. P300 hemisphere differences differentiated TD from AR and IR children. P300 amplitudes discriminated rhyming from non-rhyming words across children. Results extend prior work asserting that normalization and compensatory mechanisms are active during successful interventions.     

内隐自我正面偏见效应的ERP研究

目的:在内隐层面上探讨自我相关信息加工与情绪效价信息加工之间的关系,为内隐自我正面偏见的存在提供证据。方法:以情绪性汉语双字词为材料,采用阈上态度启动范式,在自我和非自我启动情况下,记录被试对情绪字词按正负性质完成归类判断任务时的ERPs,比较自我正面、自我负面、非自我正面、非自我负面四类信息的ERP数据。结果:内隐层面上,自我相关信息与情绪效价信息在N400波幅上表现出显著的交互作用,相对于自我负面和非自我正面信息来说,自我正面和非自我负面信息诱发的N400波幅更大,即内隐层面上对自我正面偏见范畴内的字词(自我正面和非自我负面)表现出更大的ERP负波。结论:自我相关信息和情绪效价信息的加工在内隐层面上是密切相关的,且他们之间的关系符合自我正面偏见效应,从而证实了内隐自我正面偏见的存在。     

Electrophysiological correlates of threat processing in spider phobics

The electrocortical correlates of the processing of feared/fear-relevant and neutral stimuli were investigated in a pictorial emotional Stroop paradigm with spider phobic, social phobic, and nonphobic subjects. Subjects identified either the color of red or blue pictures of spiders, birds, or flowers (emotional Stroop task) or the object itself (identification task) by pressing different buttons. No emotional Stroop interference was found for spider phobic subjects when identifying the color of spiders as opposed to neutral stimuli. However, in the object identification task, spider phobic subjects identified spiders significantly faster than birds or flowers. Parietal P300 and P400 amplitudes were enhanced independent of task in spider phobic but not in nonphobic subjects when viewing pictures of spiders, which is consistent with previous studies showing that highly unpleasant and arousing pictures affect parietal late positive potentials.     

Processing of emotional adjectives: Evidence from startle EMG and ERPs

Affective startle modulation in the electromyographic (EMG), auditory startle evoked potentials, and visually evoked potentials (VEPs) were assessed while subjects evaluated pleasant, unpleasant, and neutral adjectives. Acoustic startle probes were presented at random time points 2.5-4.0 s after word onset. The visual P2 and P3 potentials were generally larger during processing of emotional than of neutral adjectives. In contrast, the late positive component was enhanced and was correlated with larger EMG startle responses and auditory startle evoked potential P3 amplitudes for pleasant words only. During internal cognitive activity, the startle reflex represents a measure of "processing interrupt." Thus the startle tone interrupted processing of particularly pleasant adjectives and caused re-alerting to environmental stimuli. Specific effects for pleasant material may arise from a "positivity offset," favoring responses to pleasant material at lower arousal levels.     

Decreased P3 amplitudes elicited by negative facial emotion in manic patients: Selective deficits in emotional processing

Manic patients have impairments in recognizing negative emotional stimuli. However, there have been few studies on manic patients’ neurophysiological responses to facial emotions. We measured the P3 event-related potentials using facial emotional stimuli to investigate whether the impairment in recognition of negative emotions is greater in maniac patients. We recruited twenty manic patients and twenty controls. A visual oddball paradigm was used with facial pictures: happy, neutral, sad, fear, and disgust emotions. While P3 amplitudes of emotional stimuli were significantly larger than those of neutral stimuli in controls, the amplitudes were not significantly different from those for neutral pictures in manic patients. Repeated-measures analysis of variance on P3 amplitudes revealed significant interaction effects of paired emotions as sad-neutral, disgust-neutral, fear-neutral, but not in the happy-neutral emotion pairs. These differential P3 responses suggest that manic patients may have abnormal neurophysiological activity when evaluating negative facial emotions. Thus, these findings may give the evidence for reduced negative emotion recognition of manic patients.     

Emotions and airway resistance in asthma: study with whole body plethysmography

The role of emotions as potential triggers of asthmatic airway obstructions was examined by whole body plethysmography. Three affectively homogeneous picture series (IAPS) were presented with video glasses to induce pleasant, unpleasant, and neutral emotional states in 32 asthmatic and 32 nonasthmatic participants while they were seated in a Jaeger Bodytest plethysmograph. Airway resistance, specific airway resistance, thoracic gas volume, and mood were measured immediately after each presentation, in addition to specific airway resistance before and during each presentation. Airway resistance and specific airway resistance were significantly increased after and during pleasant and unpleasant stimulation compared to neutral stimulation in asthmatic patients and also, but less pronounced, in nonasthmatic controls. The results show that the experience of pleasant and unpleasant emotions can provoke increased airway resistance especially in asthmatic patients.