The interaction of anticipatory anxiety and emotional picture processing: an event-related brain potential study.

The present study examined the interaction of anticipatory anxiety and selective emotion processing. Toward this end, a rapid stream of pleasant, neutral, and unpleasant pictures was presented in alternating blocks of threat-of-shock or safety, which were signaled by colored picture frames. The main finding is that pleasant pictures elicited a sustained negative difference potential over occipital regions during threat as compared to safety periods. In contrast, unpleasant and neutral picture processing did not vary as a function of threat-of-shock. Furthermore, in both the safety and threat-of-shock conditions, emotional pictures elicited an enlarged early posterior negativity and late positive potential. These data show that the activation of the fear/anxiety network exerts valence-specific effects on affective picture processing. Pleasant stimuli mismatching the current state of anticipatory anxiety apparently draw more attentional resources.

Brain dynamics in spider-phobic individuals exposed to phobia-relevant and other emotional stimuli.

Dense sensor event-related brain potentials were measured in participants with spider phobia and nonfearful controls during viewing of phobia-relevant spider and standard emotional (pleasant, unpleasant, neutral) pictures. Irrespective of the picture content, spider phobia participants responded with larger P1 amplitudes than controls, suggesting increased vigilance in this group. Furthermore, spider phobia participants showed a significantly enlarged early posterior negativity (EPN) and late positive potential (LPP) during the encoding of phobia-relevant pictures compared to nonfearful controls. No group differences were observed for standard emotional materials indicating that these effects were specific to phobia-relevant material. Within group comparisons of the spider phobia group, though, revealed comparable EPN and LPP evoked by spider pictures and emotional (unpleasant and pleasant) picture contents. These results demonstrate a temporal unfolding in perceptual processing from unspecific vigilance (P1) to preferential responding (EPN and LPP) to phobia-relevant materials in the spider phobia group. However, at the level of early stimulus processing, these effects of increased attention seem to be related to emotional relevance of the stimulus cues rather than reflecting a fear-specific response.

The impact of hunger on food cue processing: an event-related brain potential study.

The present study used event-related brain potentials to examine deprivation effects on visual attention to food stimuli at the level of distinct processing stages. Thirty-two healthy volunteers (16 females) were tested twice 1 week apart, either after 24 h of food deprivation or after normal food intake. Participants viewed a continuous stream of food and flower images while dense sensor ERPs were recorded. As revealed by distinct ERP modulations in relatively earlier and later time windows, deprivation affected the processing of food and flower pictures. Between 300 and 360 ms, food pictures were associated with enlarged occipito-temporal negativity and centro-parietal positivity in deprived compared to satiated state. Of main interest, in a later time window (approximately 450-600 ms), deprivation increased amplitudes of the late positive potential elicited by food pictures. Conversely, flower processing varied by motivational state with decreased positive potentials in the deprived state. Minimum-Norm analyses provided further evidence that deprivation enhanced visual attention to food cues in later processing stages. From the perspective of motivated attention, hunger may induce a heightened state of attention for food stimuli in a processing stage related to stimulus recognition and focused attention.

Vegetarianism and food perception. Selective visual attention to meat pictures.

Vegetarianism provides a model system to examine the impact of negative affect towards meat, based on ideational reasoning. It was hypothesized that meat stimuli are efficient attention catchers in vegetarians. Event-related brain potential recordings served to index selective attention processes at the level of initial stimulus perception. Consistent with the hypothesis, late positive potentials to meat pictures were enlarged in vegetarians compared to omnivores. This effect was specific for meat pictures and obtained during passive viewing and an explicit attention task condition. These findings demonstrate the attention capture of food stimuli, deriving affective salience from ideational reasoning and symbolic meaning.

Deprivation selectively modulates brain potentials to food pictures.

Event-related brain potentials (ERPs) were used to examine whether the processing of food pictures is selectively modulated by changes in the motivational state of the observer. Sixteen healthy male volunteers were tested twice 1 week apart, either after 24 hr of food deprivation or after normal food intake. ERPs were measured while participants viewed appetitive food pictures as well as standard emotional and neutral control pictures. Results show that the ERPs to food pictures in a hungry, rather than satiated, state were associated with enlarged positive potentials over posterior sensor sites in a time window of 170-310 ms poststimulus. Minimum-norm analysis suggests the enhanced processing of food cues primarily in occipito-temporo-parietal regions. In contrast, processing of standard emotional and neutral pictures was not modulated by food deprivation. Considered from the perspective of motivated attention, the selective change of food cue processing may reflect a state-dependent change in stimulus salience.

The selective processing of emotional visual stimuli while detecting auditory targets: an ERP analysis.

Event-related potential studies revealed an early posterior negativity (EPN) for emotional compared to neutral pictures. Exploring the emotion-attention relationship, a previous study observed that a primary visual discrimination task interfered with the emotional modulation of the EPN component. To specify the locus of interference, the present study assessed the fate of selective visual emotion processing while attention is directed towards the auditory modality. While simply viewing a rapid and continuous stream of pleasant, neutral, and unpleasant pictures in one experimental condition, processing demands of a concurrent auditory target discrimination task were systematically varied in three further experimental conditions. Participants successfully performed the auditory task as revealed by behavioral performance and selected event-related potential components. Replicating previous results, emotional pictures were associated with a larger posterior negativity compared to neutral pictures. Of main interest, increasing demands of the auditory task did not modulate the selective processing of emotional visual stimuli. With regard to the locus of interference, selective emotion processing as indexed by the EPN does not seem to reflect shared processing resources of visual and auditory modality.

Affective prime and target picture processing: an ERP analysis of early and late interference effects.

Viewing emotionally arousing compared to neutral pictures is associated with differential electrophysiological activity in early ("early posterior negativity", EPN), as well as later time-windows ("late positive potential", LPP). A previous study revealed that the EPN is reduced when the preceding prime picture was emotional. The present study explored whether sequential interference effects are specific for early processing stages or extend to later processing stages. Dense sensor ERPs were measured while subjects viewed a continuous stream of pleasant, neutral, and unpleasant pictures, presented for 660 ms each. Previous results were replicated in that emotional pictures were associated with enlarged EPN and LPP amplitudes compared to neutral pictures. Furthermore, the EPN to emotional and neutral pictures was reduced when preceded by pleasant prime pictures. The novel finding was that emotional compared to neutral prime pictures were associated with reduced LPP amplitudes to the subsequently presented picture irrespective of its emotional valence (pleasant, neutral, unpleasant). These results demonstrate sustained interference effects in serial picture presentations discussed within a framework of resource competition among successive pictures.

Visual noise effects on emotion perception: brain potentials and stimulus identification.

Event-related potential (ERP) studies revealed an early posterior negativity (EPN) for emotionally arousing pictures. Two studies explored how this effect relates to perceptual stimulus characteristics and stimulus identification. Adding various amounts of visual noise varied stimulus perceptibility of high and low arousing picture contents, which were presented as rapid and continuous stream. Measuring dense sensor event-related potentials, study I determined that noise level was linearly related to the P1 peak. Subsequently, enlarged EPNs to emotionally arousing contents were observed, however, only for pictures containing low amounts of noise, which also enabled stimulus identification as shown by study II. These data support the notion that the EPN may serve as a measure of affective stimulus evaluation at an early transitory processing period.

Explicit attention interferes with selective emotion processing in human extrastriate cortex.

BACKGROUND: Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (approximately 150-300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. RESULTS: Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. CONCLUSION: The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon.

Selective visual attention to emotion.

Visual attention can be voluntarily directed toward stimuli and is attracted by stimuli that are emotionally significant. The present study explored the case when both processes coincide and attention is directed to emotional stimuli. Participants viewed a rapid and continuous stream of high-arousing erotica and mutilation stimuli as well as low-arousing control images. Each of the three stimulus categories served in separate runs as target or nontarget category. Event-related brain potential measures revealed that the interaction of attention and emotion varied for specific processing stages. The effects of attention and emotional significance operated additively during perceptual encoding indexed by negative-going potentials over posterior regions (approximately 200-350 ms after stimulus onset). In contrast, thought to reflect the process of stimulus evaluation, P3 target effects (approximately 400-600 ms after stimulus onset) were markedly augmented when erotica and mutilation compared with control stimuli were the focus of attention. Thus, emotion potentiated attention effects specifically during later stages of processing. These findings suggest to specify the interaction of attention and emotion in distinct processing stages.

Emotion and attention: event-related brain potential studies.

Emotional pictures guide selective visual attention. A series of event-related brain potential (ERP) studies is reviewed demonstrating the consistent and robust modulation of specific ERP components by emotional images. Specifically, pictures depicting natural pleasant and unpleasant scenes are associated with an increased early posterior negativity, late positive potential, and sustained positive slow wave compared with neutral contents. These modulations are considered to index different stages of stimulus processing including perceptual encoding, stimulus representation in working memory, and elaborate stimulus evaluation. Furthermore, the review includes a discussion of studies exploring the interaction of motivated attention with passive and active forms of attentional control. Recent research is reviewed exploring the selective processing of emotional cues as a function of stimulus novelty, emotional prime pictures, learned stimulus significance, and in the context of explicit attention tasks. It is concluded that ERP measures are useful to assess the emotion-attention interface at the level of distinct processing stages. Results are discussed within the context of two-stage models of stimulus perception brought out by studies of attention, orienting, and learning.

Stimulus novelty and emotion perception: the near absence of habituation in the visual cortex.

In rapid serial visual presentation of pictures, an early event-related brain potential component shows enlarged negativity over occipital regions for emotional pictures compared with neutral pictures. The present study examined whether the processing of emotional target pictures varies as a function of stimulus repetition. Accordingly, pictures of erotica, neutral contents, and mutilations were repeatedly presented (90 times) while the electroencephalogram was recorded with a 129 dense sensor array. As in previous studies, emotional pictures were associated with a larger posterior negativity than neutral pictures. Furthermore, differential emotion processing did not vary as a function of stimulus repetition and was similarly expressed across blocks of picture presentation. These findings suggest the near absence of habituation in differential emotion processing during perceptual processing.

The facilitated processing of threatening faces: an ERP analysis.

Threatening, friendly, and neutral faces were presented to test the hypothesis of the facilitated perceptual processing of threatening faces. Dense sensor event-related brain potentials were measured while subjects viewed facial stimuli. Subjects had no explicit task for emotional categorization of the faces. Assessing early perceptual stimulus processing, threatening faces elicited an early posterior negativity compared with nonthreatening neutral or friendly expressions. Moreover, at later stages of stimulus processing, facial threat also elicited augmented late positive potentials relative to the other facial expressions, indicating the more elaborate perceptual analysis of these stimuli. Taken together, these data demonstrate the facilitated perceptual processing of threatening faces. Results are discussed within the context of an evolved module of fear (A. Ohman & S. Mineka, 2001).