Fleeting images: rapid affect discrimination in the visual cortex

Emotional text messages affect the early processing of emoticons depending on their emotional congruence: evidence from the N170 and EPN event related potentials

Emoticons have been considered pragmatic cues that enhance emotional expressivity during computer-mediated communication. Yet, it is unclear how emoticons are processed in ambiguous text-based communication due to incongruences between the emoticon's emotional valence and its context. In this study, we investigated the electrophysiological correlates of contextual influence on the early emotional processing of emoticons, during an emotional congruence judgment task. Participants were instructed to judge the congruence between a text message expressing an emotional situation (positive or negative), and a subsequent emoticon expressing positive or negative emotions. We analyzed early event-related potentials elicited by emoticons related to face processing (N170) and emotional salience in visual perception processing (Early Posterior Negativity, EPN). Our results show that accuracy and Reaction Times depend on the interaction between the emotional valence of the context and the emoticon. Negative emoticons elicited a larger N170, suggesting that the emotional information of the emoticon is integrated at the early stages of the perceptual process. During emoticon processing, a valence effect was observed with enhanced EPN amplitudes in occipital areas for emoticons representing negative valences. Moreover, we observed a congruence effect in parieto-temporal sites within the same time-window, with larger amplitudes for the congruent condition. We conclude that, similar to face processing, emoticons are processed differently according to their emotional content and the context in which they are embedded. A congruent context might enhance the emotional salience of the emoticon (and therefore, its emotional expression) during the early stages of their processing.

Predictability modulates the early neural coding of spatially unattended fearful faces

In this study, we assessed whether predictability affected the early processing of facial expressions. To achieve this, we measured lateralised early- and mid-latency event-related potentials associated with visual processing. Twenty-two participants were shown pairs of bilaterally presented fearful, happy, angry, or scrambled faces. Participants were required to identify angry faces on a spatially attended side whilst ignoring happy, fearful, and scrambled faces. Each block began with the word HAPPY or FEARFUL which informed participants the probability at which these faces would appear. Attention effects were found for the lateralised P1, suggesting that emotions do not modulate the P1 differentially, nor do predictions relating to emotions. Pairwise comparisons demonstrated that, when spatially unattended, unpredicted fearful faces produced larger lateralised N170 amplitudes compared to predicted fearful faces and unpredicted happy faces. Finally, attention towards faces increased lateralised EPN amplitudes, as did both fearful expressions and low predictability. Thus, we demonstrate that the N170 and EPN are sensitive to top-down predictions relating to facial expressions and that low predictability appears to specifically affect the early encoding of fearful faces when unattended, possibly to initiate attentional capture.

Topology of the lateral visual system: The fundus of the superior temporal sulcus and parietal area H connect nonvisual cerebrum to the lateral occipital lobe

BACKGROUND AND PURPOSE

Mapping the topology of the visual system is critical for understanding how complex cognitive processes like reading can occur. We aim to describe the connectivity of the visual system to understand how the cerebrum accesses visual information in the lateral occipital lobe.

METHODS

Using meta-analytic software focused on task-based functional MRI studies, an activation likelihood estimation (ALE) of the visual network was created. Regions of interest corresponding to the cortical parcellation scheme previously published under the Human Connectome Project were co-registered onto the ALE to identify the hub-like regions of the visual network. Diffusion Spectrum Imaging-based fiber tractography was performed to determine the structural connectivity of these regions with extraoccipital cortices.

RESULTS

The fundus of the superior temporal sulcus (FST) and parietal area H (PH) were identified as hub-like regions for the visual network. FST and PH demonstrated several areas of coactivation beyond the occipital lobe and visual network. Furthermore, these parcellations were highly interconnected with other cortical regions throughout extraoccipital cortices related to their nonvisual functional roles. A cortical model demonstrating connections to these hub-like areas was created.

CONCLUSIONS

FST and PH are two hub-like areas that demonstrate extensive functional coactivation and structural connections to nonvisual cerebrum. Their structural interconnectedness with language cortices along with the abnormal activation of areas commonly located in the temporo-occipital region in dyslexic individuals suggests possible important roles of FST and PH in the integration of information related to language and reading. Future studies should refine our model by examining the functional roles of these hub areas and their clinical significance.

Electrophysiological correlates of in vivo and virtual reality exposure therapy in spider phobia

Specific phobia can be treated successfully with exposure therapy. Although exposure therapy has strong effects on self-reported ratings and behavioral avoidance, effects on measures derived from electroencephalography (EEG) are scant and unclear. To fill this gap, spider-phobic individuals received either in-vivo or virtual reality exposure treatment. Patients were tested twice (one week before and after treatment), and control subjects once. In each session, EEG was recorded to spider pictures as well as other positive, negative, and neutral pictures. During EEG recording, participants performed a simple detection task while task-irrelevant pictures were shown in the background. The task was used to reduce potential confounding effects from shifts of attention. After the task, subjects were shown the pictures again and rated each in terms of their emotional reaction (arousal and pleasantness). The results showed that before treatment, patients rated spiders as more negative than did control subjects. Patients also showed elevated early posterior negativity (EPN) and late positive potential (LPP) to spiders. After treatment, the negative emotional ratings of spiders were substantially reduced. Critically, Bayesian analyses suggested that EPN and LPP were unaffected by treatment and that the treatment groups did not differ in their responses (EPN, LPP, and ratings). These findings suggest that the effects of in vivo and virtual reality exposure therapy are similar and that the initial stages of motivated attention (EPN and LPP) are unaffected by treatment.

Neural Processing Differences of Facial Emotions Between Human and Vehicles: Evidence From an Event-Related Potential Study

Vehicle “faces” are a crucial factor influencing consumer intention to purchase gasoline and electric vehicles. However, little empirical evidence has demonstrated whether people process a vehicle’s face similarly to a human’s face. We investigated the neural processing relationship among human facial emotions and facial emotions of gasoline and electric vehicles using a 2 (emotional) × 3 (face type) repeated measures design and electroencephalograph (EEG) recordings. The results showed that human faces appear to share a partly similar neural processing mechanism in the latency of 100–300 ms, and that both human and vehicle faces elicited the ERP components N170, EPN, and P2. The large EPN and P2 suggest that gasoline vehicle facial emotions can be perceived more efficiently than those of electric vehicles. These findings provide an insight for vehicle designers to better understand the facial emotions presented by cars.

Visual competition attenuates emotion effects during overt attention shifts

Numerous different objects are simultaneously visible in a person's visual field, competing for attention. This competition has been shown to affect eye-movements and early neural responses toward stimuli, while the role of a stimulus' emotional meaning for mechanisms of overt attention shifts under competition is unclear. The current study combined EEG and eye-tracking to investigate effects of competition and emotional content on overt shifts of attention to human face stimuli. Competition prolonged the latency of the P1 component and of saccades, while faces showing emotional expressions elicited an early posterior negativity (EPN). Remarkably, the emotion-related modulation of the EPN was attenuated when two stimuli were competing for attention compared to non-competition. In contrast, no interaction effects of emotional expression and competition were observed on other event-related potentials. This finding indicates that competition can decelerate attention shifts in general and also diminish the emotion-driven attention capture, measured through the smaller effects of emotional expression on EPN amplitude. Reduction of the brain's responsiveness to emotional content in the presence of distractors contradicts models that postulate fully automatic processing of emotions.

Right medial temporal lobe structures particularly impact early stages of affective picture processing

Human vision prioritizes emotional stimuli. This is reflected in stronger electrocortical activation in response to emotional than neutral stimuli, measurable on the surface of the head. Feedback projections from brain structures deep within the medial temporal lobes (mTLs), in particular the amygdala, are thought to give rise to this phenomenon, although causal evidence is rare. Given the many pathways involved in visual processing, the influence of mTL structures could be restricted to specific time windows. Therefore, we delineate the temporal dynamics of the impact of right mTL structures on affective picture processing, investigating event-related potentials (ERPs) in 19 patients (10 female) with right mTL resections and 19 individually matched healthy participants, while they viewed negative and neutral scenes. Groups differed significantly at early- and mid-latency processing stages. Patients with right mTL resection, unlike controls, showed no (P1: 90-140 ms) or marginal (N1: 170-220 ms) emotion modulation. At mid-latency (early posterior negativity: 220-370 ms), emotion modulation over the ipsi-resectional right hemisphere was smaller in patients than in controls, but groups did not differ over the left hemisphere. During late parietal positivities (400-650 ms and 650-900 ms), both groups had similar emotion modulation. Our results demonstrate that right mTL structures attenuate particularly early processing of affectively negative scenes. This is theoretically consistent with an initial amygdala-dependent feedforward sweep in visual emotion processing whose absence is successively compensated. Findings specify the impact of right mTL structures on emotional picture processing and highlight the value of time-resolved measures in affective neuroscience.

fMRI replicability during emotional scene viewing: Functional regions and sample size

Recent findings have questioned the replicability of functional magnetic resonance imaging (fMRI) in the study of affective processing, reporting low replicability of emotional enhancement during a face-matching task. However, poor replicability may instead reflect a lack of emotional engagement for face matching. In the current study, replicability of emotional enhancement was tested in a large (N = 160) sample when emotional engagement was assessed during pleasant, neutral, and unpleasant picture viewing, which reliably engages affective reactions in both the brain and the body. Replicability was computed using a subsampling technique, in which random sets of subjects of different sample sizes (N = 20, 40, 60, 80) were selected from the entire dataset, and replicability of emotional enhancement for peaks, clusters, and voxels were averaged across 500 permutations for each sample size. Consistent with previous findings, fMRI replicability increased with increasing sample size. On the other hand, even with relatively small samples, fMRI replicability for peaks, clusters, and voxels during emotional, compared to neutral, scene viewing was good to excellent. Importantly, replicability varied in different brain regions, with excellent replicability at both the cluster and peak level with an N of 40, at the most conservative threshold (p < .001), in the amygdala and the visual cortex. The data argue against general recommendations regarding sample size in fMRI studies of emotion, suggesting instead that degree of replicability depends on successful emotional engagement in task-related brain regions.

CA, Klingner CM. The Right Hemisphere Is Responsible for the Greatest Differences in Human Brain Response to High-Arousing Emotional versus Neutral Stimuli: A MEG Study

Studies investigating human brain response to emotional stimuli-particularly high-arousing versus neutral stimuli-have obtained inconsistent results. The present study was the first to combine magnetoencephalography (MEG) with the bootstrapping method to examine the whole brain and identify the cortical regions involved in this differential response. Seventeen healthy participants (11 females, aged 19 to 33 years; mean age, 26.9 years) were presented with high-arousing emotional (pleasant and unpleasant) and neutral pictures, and their brain responses were measured using MEG. When random resampling bootstrapping was performed for each participant, the greatest differences between high-arousing emotional and neutral stimuli during M300 (270-320 ms) were found to occur in the right temporo-parietal region. This finding was observed in response to both pleasant and unpleasant stimuli. The results, which may be more robust than previous studies because of bootstrapping and examination of the whole brain, reinforce the essential role of the right hemisphere in emotion processing.

Overt and covert attention shifts to emotional faces: Combining EEG, eye tracking, and a go/no-go paradigm

In everyday life, faces with emotional expressions quickly attract attention and eye movements. To study the neural mechanisms of such emotion-driven attention by means of event-related brain potentials (ERPs), tasks that employ covert shifts of attention are commonly used, in which participants need to inhibit natural eye movements towards stimuli. It remains, however, unclear how shifts of attention to emotional faces with and without eye movements differ from each other. The current preregistered study aimed to investigate neural differences between covert and overt emotion-driven attention. We combined eye tracking with measurements of ERPs to compare shifts of attention to faces with happy, angry, or neutral expressions when eye movements were either executed (go conditions) or withheld (no-go conditions). Happy and angry faces led to larger EPN amplitudes, shorter latencies of the P1 component, and faster saccades, suggesting that emotional expressions significantly affected shifts of attention. Several ERPs (N170, EPN, LPC) were augmented in amplitude when attention was shifted with an eye movement, indicating an enhanced neural processing of faces if eye movements had to be executed together with a reallocation of attention. However, the modulation of ERPs by facial expressions did not differ between the go and no-go conditions, suggesting that emotional content enhances both covert and overt shifts of attention. In summary, our results indicate that overt and covert attention shifts differ but are comparably affected by emotional content.

The Behavioral and ERP Responses to Self- and Other- Referenced Adjectives

The aim was to investigate behavioral reactions and event-related potential (ERP) responses in healthy participants under conditions of personalized attribution of emotional appraisal vocabulary to one-self or to other people. One hundred and fifty emotionally neutral, positive and negative words describing people's traits were used. Subjects were asked to attribute each word to four types of people: one-self, loved, unpleasant and neutral person. The reaction time during adjectives attribution to one-self and a loved person was shorter than during adjectives attribution to neutral and unpleasant people. Self-related adjectives induced higher amplitudes of the N400 ERP peak in the medial cortical areas in comparison with adjectives related to other people. The amplitude of P300 and P600 depended on the emotional valence of assessments, but not on the personalized attribution. The interaction between the attribution effect and the effect of emotional valence of assessments was observed for the N400 peak in the left temporal area. The maximal amplitude of N400 was revealed under self-attributing of emotionally positive adjectives. Our results supported the hypothesis that the emotional valence of assessments and the processing of information about one-self or others were related to the brain processes that differ from each other in a cortical localization or time dynamics.

Neural correlates of top-down guidance of attention to food: An fMRI study

We investigated the neural correlates of working memory guided attentional selection of food versus non-food stimuli in young women. Participants were thirty-two women, aged 20.6y (± 0.5) who were presented with a cue (food or non-food item) to hold in working memory. Subsequently, they had to search for a target in a 2-item display where target and distractor stimuli were each flanked by a picture of a food or a non-food item. The behavioural data showed that attention is particularly efficiently drawn to food stimuli when thinking about food. Using fMRI, we found that holding a non-food versus food stimulus in working memory was associated with increased activity in occipital gyrus, fusiform, inferior and superior frontal gyrus. In the posterior cingulum, retrosplenial cortex, a food item that re-appeared in the search array when it was held in memory led to a reduced response, compared to when it did not re-appear. The reverse effect was found for non-food stimuli. The extent of the reappearance effect correlated with the attentional capture of food as measured behaviourally. In conclusion, these results suggest that holding food in mind may bias attention because thinking of food facilitated neuronal responses to sensory input related to food stimuli and because holding food-related information in mind is less taxing on memory.

Conjunctive and Elemental Representations of a Context in Humans

The dual-process theory assumes that contexts are encoded in an elemental and in a conjunctive representation. However, this theory was developed from animal studies, and we still have to explore if and how elemental and conjunctive representations contribute to, for example, contextual anxiety in humans. Therefore, 28 participants underwent differential context conditioning in a newly developed flip-book paradigm. Virtual rooms were presented similar to a flip-book, that is, as a stream of 49 consecutive screenshots creating the impression of walking through the rooms. This allowed registration of event-related brain potentials triggered by specific screenshots. During two acquisition phases, two rooms were shown in this way for six times each. In one room, the anxiety context (CTX+), mildly painful electric stimuli (unconditioned stimuli [USs]) were administered unpredictably after 12 distinct screenshots, which became threat elements, whereas 12 selected comparable screenshots became nonthreat elements (elemental representation); all screenshots represented the anxiety context (conjunctive representation). In the second room, the safety context (CTX-), no USs were applied; thus, all screenshots created the safety context whereby 12 preselected screenshots represented safety elements. Increased US expectancy ratings for threat versus nonthreat or safety elements reflected elemental representation. Conjunctive representation was evident in differential ratings (arousal and contingency) and increased P100 and early posterior negativity amplitudes for threat and nonthreat CTX+ versus safety CTX- screenshots. These differences disappeared during two test phases without US delivery indicating successful extinction. In summary, we revealed the first piece of evidence for the simultaneous contributions of elemental and conjunctive representation during context conditioning in humans.

Common circuit or paradigm shift? The functional brain in emotional scene perception and emotional imagery

Meta-analytic and experimental studies investigating the neural basis of emotion often compare functional activation in different emotional induction contexts, assessing evidence for a "core affect" or "salience" network. Meta-analyses necessarily aggregate effects across diverse paradigms and different samples, which ignore potential neural differences specific to the method of affect induction. Data from repeated measures designs are few, reporting contradictory results with a small N. In the current study, functional brain activity is assessed in a large (N = 61) group of healthy participants during two common emotion inductions-scene perception and narrative imagery-to evaluate cross-paradigm consistency. Results indicate that limbic and paralimbic regions, together with visual and parietal cortex, are reliably engaged during emotional scene perception. For emotional imagery, in contrast, enhanced functional activity is found in several cerebellar regions, hippocampus, caudate, and dorsomedial prefrontal cortex, consistent with the conception that imagery is an action disposition. Taken together, the data suggest that a common emotion network is not engaged across paradigms, but that the specific neural regions activated during emotional processing can vary significantly with the context of the emotional induction.

Deconstructing threat: Rethinking the interplay between biological and social relevance in the emotional salience of unpleasant images

The type of threat shown in an image influences the emotional salience of unpleasant images. Seventy-four participants (21 male) rated high threat, moderate threat, and neutral images featuring reptiles, firearms, or humans as electroencephalographic activity was recorded. The magnitude of P3b amplitudes coincided with the threat level of firearm and human images, whereas scenes of attacking snakes and aimed handguns evoked more positive late positive component (LPC) activity than non-attacking or neutral versions of these same stimuli. The lateralised early posterior negativity (EPN) in temporal occipital regions was most negative for firearms, followed by reptiles, and then humans, while the midline EPN in occipital regions was most negative for reptiles, followed by firearms, and then humans. These findings imply late event-related potential positivity is influenced by social relevance (the P3b) or the level of aggression displayed by the stimulus (the LPC), whereas stimulus type may be indexed by EPN modulation.

Emotional and feature-based modulation of the early posterior negativity

The early posterior negativity (EPN) has been shown to be enhanced by emotional relative to neutral scene perception. A subset of studies has also reported a bias in the EPN toward pleasant relative to unpleasant scenes. Functional MRI research has also identified a region in lateral occipital cortex that shows a sensitivity to the visual perception of body parts, which may contribute to the EPN. Here, we assess the roles of rated scene pleasantness and the depiction of body parts on modulation of the EPN in two studies, using scenes that are chosen to be of equivalent perceptual complexity. In Study 1, we presented two distinct highly pleasant and arousing scene contents (erotic couples and moments of jubilant victory) as well as neutral people, threat, and mutilation scenes. As in prior research, the EPN was enhanced by emotionally arousing scenes, with the greatest modulation evoked by erotic scenes, although victory scenes elicited stronger ratings of pleasantness and equivalent ratings of arousal. This result suggests that the EPN may be sensitive to distinct features found in erotic scenes. To determine the extent to which body part perception modulates the EPN, Study 2 compared EPN modulation evoked by erotic scenes with nonerotic nudist scenes. Ratings of pleasantness and arousal were reduced, yet nudist scenes led to stronger modulation of the EPN compared to erotic scenes. These data indicate that, in addition to the emotional intensity of scenes, modulation of the EPN may in part reflect the discrimination of unclothed body parts.

Bad words prevail: Negatively charged Chinese characters accelerate attentional selection and preoccupy cognitive resources for consolidation

Previous studies have produced contradictory findings regarding whether emotion exerts facilitative effects or inhibitory effects on perception. In the present study, we hypothesized that attention can be separated into the initial selection stage and the latter consolidation stage, and emotion plays a different role in each of these two stages. To test this hypothesis, we adopted the dual-stream rapid serial visual presentation paradigm (Goodbourn & Holcombe, Journal of Experimental Psychology: Human Perception and Performance, 41(2), 364–384, 2015), which provided separate measurements for selection latency (how delayed the attentional selection process is) and efficacy (how much information can be successfully consolidated for conscious report). The results suggested emotion’s dual role on perception. Firstly, the presence of negatively charged visual targets (which were Chinese characters in the present study) accelerated attention selection, and the acceleration effect could spread to different locations in the visual field. Secondly, negatively charged characters preoccupied attentional resources for consolidation, yielding location-specific facilitative and inhibitory effects.

Rapid brain responses to affective pictures indicate dimensions of trauma-related psychopathology in adolescents

A variety of mental disorders are related to deviant brain activity, but these neural alterations do not validate psychiatric diagnostic categories. High symptom overlap and variable symptom patterns encourage a dimensional approach. Following the logic of the Research Domain Criteria (RDoC), we investigated trauma survivors for symptom clusters that might be associated with characteristics of ERPs, in particular with the early posterior negativity (EPN) elicited during affective picture processing. In rapid serial visual presentation, 90 adolescents (40 male/50 female, age M = 15.0 ± 2.5 years) who had been exposed to varying amounts of traumatic stress passively viewed a stream of high‐arousing positive and low‐arousing neutral pictures taken from the International Affective Picture System (IAPS). Using standardized interviews, symptoms of trauma‐related mental disorders were assessed (including those for PTSD, depression, borderline personality disorder, and behavioral problems). A principal component analysis was performed to derive potential dimensions of psychopathology. Multiple regression analysis confirmed a factor comprising problems concentrating, sleeping difficulties, and mistrust as a predictor of a larger EPN difference between high‐arousing positive and low‐arousing neutral IAPS pictures (β = 0.19, p < 0.05). Sex predicted the magnitude of the EPN (β = 0.45, p < 0.001). Male adolescents displayed a stronger EPN suppression than female adolescents. The result suggests that problems concentrating, sleeping difficulties, and mistrust seem to be trans‐diagnostic elements related to diminished early emotional discrimination represented by the EPN. Furthermore, our findings indicate that the EPN in response to emotional processing is modulated by sex.

Based on the RDoC heuristic, symptom clusters that may be associated with the early posterior negativity (EPN) elicited during affective picture processing were investigated in youth trauma survivors. Analysis confirmed a factor comprising problems concentrating, sleeping difficulties, and mistrust as a predictor of a larger EPN difference between high arousing positive and low arousing neutral IAPS pictures using rapid serial visual presentation (RSVP). The EPN component was also modulated by sex. The findings also extend those of prior research on emotional processing confirming that EPN suppression can also be found in adolescents.

How the Dorsolateral Prefrontal Cortex Controls Affective Processing in Absence of Visual Awareness - Insights From a Combined EEG-rTMS Study

The dorsolateral prefrontal cortex (DLPFC) plays a key role in the modulation of affective processing. However, its specific role in the regulation of neurocognitive processes underlying the interplay of affective perception and visual awareness has remained largely unclear. Using a mixed factorial design, this study investigated effects of inhibitory continuous theta-burst stimulation (cTBS) of the right DLPFC (rDLPFC) compared to an Active Control condition on behavioral (N = 48) and electroencephalographic (N = 38) correlates of affective processing in healthy Chinese participants. Event-related potentials (ERPs) in response to passively viewed subliminal and supraliminal negative and neutral natural scenes were recorded before and after cTBS application. We applied minimum-norm approaches to estimate the corresponding neuronal sources. On a behavioral level, we found evidence for reduced emotional interference by, and less negative and aroused ratings of negative supraliminal stimuli following rDLPFC inhibition. We found no evidence for stimulation effects on self-reported mood or the behavioral discrimination of subliminal stimuli. On a neurophysiological level, rDLPFC inhibition relatively enhanced occipito-parietal brain activity for both subliminal and supraliminal negative compared to neutral images (112–268 ms; 320–380 ms). The early onset and localization of these effects suggests that rDLPFC inhibition boosts automatic processes of “emotional attention” independently of visual awareness. Further, our study reveals the first available evidence for a differential influence of rDLPFC inhibition on subliminal versus supraliminal neural emotion processing. Explicitly, our findings indicate that rDLPFC inhibition selectively enhances late (292–360 ms) activity in response to supraliminal negative images. We tentatively suggest that this differential frontal activity likely reflects enhanced awareness-dependent down-regulation of negative scene processing, eventually leading to facilitated disengagement from and less negative and aroused evaluations of negative supraliminal stimuli.

Disentangling brain activity related to the processing of emotional visual information and emotional arousal

Processing of emotional visual information engages cognitive functions and induces arousal. We aimed to examine the modulatory role of emotional valence on brain activations linked to the processing of visual information and those linked to arousal. Participants were scanned and their pupil size was measured while viewing negative and neutral images. The visual noise was added to the images in various proportions to parametrically manipulate the amount of visual information. Pupil size was used as an index of physiological arousal. We show that arousal induced by the negative images, as compared to the neutral ones, is primarily related to greater amygdala activity while increasing visibility of negative content to enhanced activity in the lateral occipital complex (LOC). We argue that more intense visual processing of negative scenes can occur irrespective of the level of arousal. It may suggest that higher areas of the visual stream are fine-tuned to process emotionally relevant objects. Both arousal and processing of emotional visual information modulated activity within the ventromedial prefrontal cortex (vmPFC). Overlapping activations within the vmPFC may reflect the integration of these aspects of emotional processing. Additionally, we show that emotionally-evoked pupil dilations are related to activations in the amygdala, vmPFC, and LOC.

Effects of Scene Properties and Emotional Valence on Brain Activations: A Fixation-Related fMRI Study

Temporal and spatial characteristics of fixations are affected by image properties, including high-level scene characteristics, such as object-background composition, and low-level physical characteristics, such as image clarity. The influence of these factors is modulated by the emotional content of an image. Here, we aimed to establish whether brain correlates of fixations reflect these modulatory effects. To this end, we simultaneously scanned participants and measured their eye movements, while presenting negative and neutral images in various image clarity conditions, with controlled object-background composition. The fMRI data were analyzed using a novel fixation-based event-related (FIBER) method, which allows the tracking of brain activity linked to individual fixations. The results revealed that fixating an emotional object was linked to greater deactivation in the right lingual gyrus than fixating the background of an emotional image, while no difference between object and background was found for neutral images. We suggest that deactivation in the lingual gyrus might be linked to inhibition of saccade execution. This was supported by fixation duration results, which showed that in the negative condition, fixations falling on the object were longer than those falling on the background. Furthermore, increase in the image clarity was correlated with fixation-related activity within the lateral occipital complex, the structure linked to object recognition. This correlation was significantly stronger for negative images, presumably due to greater deployment of attention towards emotional objects. Our eye-tracking results are in line with these observations, showing that the chance of fixating an object rose faster for negative images over neutral ones as the level of noise decreased. Overall, our study demonstrated that emotional value of an image changes the way that low and high-level scene properties affect the characteristics of fixations. The fixation-related brain activity is affected by the low-level scene properties and this impact differs between negative and neutral images. The high-level scene properties also affect brain correlates of fixations, but only in the case of the negative images.

Motivational Salience Modulates Early Visual Cortex Responses across Task Sets

Motivationally relevant stimuli benefit from strengthened sensory processing. It is unclear, however, if motivational value of positive and negative valence has similar or dissociable effects on early visual processing. Moreover, whether these perceptual effects are task-specific, stimulus-specific, or more generally feature-based is unknown. In this study, we compared the effects of positive and negative motivational value on early sensory processing using ERPs. We tested the extent to which these effects could generalize to new task contexts and to stimuli sharing common features with the motivationally significant ones. At the behavioral level, stimuli paired with positive incentives were learned faster than stimuli paired with neutral or negative outcomes. The ERP results showed that monetary loss elicited higher neural activity in V1 (at the C1 level) compared with reward, whereas the latter influenced postperceptual processing stages (P300). Importantly, the early loss-related effect generalized to new contexts and to new stimuli with common features, whereas the later reward effects did not spill over to the new context. These results suggest that acquired negative motivational salience can influence early sensory processing by means of plastic changes in feature-based processing in V1.

Motivated attention and family risk for depression: Neuronal generator patterns at scalp elicited by lateralized aversive pictures reveal blunted emotional responsivity

Behavioral and electrophysiologic evidence suggests that major depression (MDD) involves right parietotemporal dysfunction, a region activated by arousing affective stimuli. Building on prior event-related potential (ERP) findings (Kayser et al. 2016 NeuroImage 142:337–350), this study examined whether these abnormalities also characterize individuals at clinical high risk for MDD. We systematically explored the impact of family risk status and personal history of depression and anxiety on three distinct stages of emotional processing comprising the late positive potential (LPP). ERPs (72 channels) were recorded from 74 high and 53 low risk individuals (age 13–59 years, 58 male) during a visual half-field paradigm using highly-controlled pictures of cosmetic surgery patients showing disordered (negative) or healed (neutral) facial areas before or after treatment. Reference-free current source density (CSD) transformations of ERP waveforms were quantified by temporal principal components analysis (tPCA). Component scores of prominent CSD-tPCA factors sensitive to emotional content were analyzed via permutation tests and repeated measures ANOVA for mixed factorial designs with unstructured covariance matrix, including gender, age and clinical covariates. Factor-based distributed inverse solutions provided descriptive estimates of emotional brain activations at group level corresponding to hierarchical activations along ventral visual processing stream. Risk status affected emotional responsivity (increased positivity to negative-than-neutral stimuli) overlapping early N2 sink (peak latency 212 ms), P3 source (385 ms), and a late centroparietal source (630 ms). High risk individuals had reduced right-greater-than-left emotional lateralization involving occipitotemporal cortex (N2 sink) and bilaterally reduced emotional effects involving posterior cingulate (P3 source) and inferior temporal cortex (630 ms) when compared to those at low risk. While the early emotional effects were enhanced for left hemifield (right hemisphere) presentations, hemifield modulations did not differ between risk groups, suggesting top-down rather than bottom-up effects of risk. Groups did not differ in their stimulus valence or arousal ratings. Similar effects were seen for individuals with a lifetime history of depression or anxiety disorder in comparison to those without. However, there was no evidence that risk status and history of MDD or anxiety disorder interacted in their impact on emotional responsivity, suggesting largely independent attenuation of attentional resource allocation to enhance perceptual processing of motivationally salient stimuli. These findings further suggest that a deficit in motivated attention preceding conscious awareness may be a marker of risk for depression.

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Emotional hemifield ERP task with 127 individuals at high and low family risk for MDD

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CSD-PCA methods summarized affective modulation of late positive potential (LPP).

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High risk and prior diagnosis of MDD or anxiety disorder independently reduced LPP.

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Suggested hypoarousal (top-down) of right temporoparietal and other emotional regions

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Left hemifield (bottom-up) modulations of early emotional asymmetries were preserved.

Newly-formed emotional memories guide selective attention processes: Evidence from event-related potentials

Emotional cues can guide selective attention processes. However, emotional stimuli can both activate long-term memory representations reflecting general world knowledge and engage newly formed memory representations representing specific knowledge from the immediate past. Here, the self-completion feature of associative memory was utilized to assess the regulation of attention processes by newly-formed emotional memory. First, new memory representations were formed by presenting pictures depicting a person either in an erotic pose or as a portrait. Afterwards, to activate newly-built memory traces, edited pictures were presented showing only the head region of the person. ERP recordings revealed the emotional regulation of attention by newly-formed memories. Specifically, edited pictures from the erotic compared to the portrait category elicited an early posterior negativity and late positive potential, similar to the findings observed for the original pictures. A control condition showed that the effect was dependent on newly-formed memory traces. Given the large number of new memories formed each day, they presumably make an important contribution to the regulation of attention in everyday life.

Neuronal generator patterns at scalp elicited by lateralized aversive pictures reveal consecutive stages of motivated attention

Event-related potential (ERP) studies have provided evidence for an allocation of attentional resources to enhance perceptual processing of motivationally salient stimuli. Emotional modulation affects several consecutive components associated with stages of affective-cognitive processing, beginning as early as 100-200ms after stimulus onset. In agreement with the notion that the right parietotemporal region is critically involved during the perception of arousing affective stimuli, some ERP studies have reported asymmetric emotional ERP effects. However, it is difficult to separate emotional from non-emotional effects because differences in stimulus content unrelated to affective salience or task demands may also be associated with lateralized function or promote cognitive processing. Other concerns pertain to the operational definition and statistical independence of ERP component measures, their dependence on an EEG reference, and spatial smearing due to volume conduction, all of which impede the identification of distinct scalp activation patterns associated with affective processing. Building on prior research using a visual half-field paradigm with highly controlled emotional stimuli (pictures of cosmetic surgery patients showing disordered [negative] or healed [neutral] facial areas before or after treatment), 72-channel ERPs recorded from 152 individuals (ages 13-68years; 81 female) were transformed into reference-free current source density (CSD) waveforms and submitted to temporal principal components analysis (PCA) to identify their underlying neuronal generator patterns. Using both nonparametric randomization tests and repeated measures ANOVA, robust effects of emotional content were found over parietooccipital regions for CSD factors corresponding to N2 sink (212ms peak latency), P3 source (385ms) and a late centroparietal source (630ms), all indicative of greater positivity for negative than neutral stimuli. For the N2 sink, emotional effects were right-lateralized and modulated by hemifield, with larger amplitude and asymmetry for left hemifield (right hemisphere) presentations. For all three factors, more positive amplitudes at parietooccipital sites were associated with increased ratings of negative valence and greater arousal. Distributed inverse solutions of the CSD-PCA-based emotional effects implicated a sequence of maximal activations in right occipitotemporal cortex, bilateral posterior cingulate cortex, and bilateral inferior temporal cortex. These findings are consistent with hierarchical activations of the ventral visual pathway reflecting subsequent processing stages in response to motivationally salient stimuli.

A novel method for classifying cortical state to identify the accompanying changes in cerebral hemodynamics

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We classified brain state using a vector-based categorisation of neural frequencies.

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Changes in cerebral blood volume (CBV) were observed when brain state altered.

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During these state alterations, changes in blood oxygenation were also found.

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State dependent haemodynamic changes could affect blood based brain imaging.

Background

Many brain imaging techniques interpret the haemodynamic response as an indirect indicator of underlying neural activity. However, a challenge when interpreting this blood based signal is how changes in brain state may affect both baseline and stimulus evoked haemodynamics.

New method

We developed an Automatic Brain State Classifier (ABSC), validated on data from anaesthetised rodents. It uses vectorised information obtained from the windowed spectral frequency power of the Local Field Potential. Current state is then classified by comparing this vectorised information against that calculated from state specific training datasets.

Results

The ABSC identified two user defined brain states (synchronised and desynchronised), with high accuracy (∼90%). Baseline haemodynamics were found to be significantly different in the two identified states. During state defined periods of elevated baseline haemodynamics we found significant decreases in evoked haemodynamic responses to somatosensory stimuli.

Comparison to existing methods

State classification – The ABSC (∼90%) demonstrated greater accuracy than clustering (∼66%) or ‘power threshold’ (∼64%) methods of comparison.

Haemodynamic averaging – Our novel approach of selectively averaging stimulus evoked haemodynamic trials by brain state yields higher quality data than creating a single average from all trials.

Conclusions

The ABSC can account for some of the commonly observed trial-to-trial variability in haemodynamic responses which arises from changes in cortical state. This variability might otherwise be incorrectly attributed to alternative interpretations. A greater understanding of the effects of cortical state on haemodynamic changes could be used to inform techniques such as general linear modelling (GLM), commonly used in fMRI.

Prepare for scare-Impact of threat predictability on affective visual processing in spider phobia

The visual processing of emotional faces is influenced by individual's level of stress and anxiety. Valence unspecific affective processing is expected to be influenced by predictability of threat. Using a design of phasic fear (predictable threat), sustained anxiety (unpredictable threat) and safety (no threat), we investigated the magnetoencephalographic correlates and temporal dynamics of emotional face processing in a sample of phobic patients. Compared to non-anxious controls, phobic individuals revealed decreased parietal emotional attention processes during affective processing at mid-latency and late processing stages. While control subjects showed increasing parietal processing of the facial stimuli in line with decreasing threat predictability, phobic subjects revealed the opposite pattern. Decreasing threat predictability also led to increasing neural activity in the orbitofrontal and dorsolateral prefrontal cortex at mid-latency stages. Additionally, unpredictability of threat lead to higher subjective discomfort compared to predictability of threat and no threat safety condition. Our findings indicate that visual processing of emotional information is influenced by both stress induction and pathologic anxiety.

Attentional enhancement for positive and negative tones at an early stage of auditory processing

We report an event-related potential (ERP) study based on the hypothesis that valenced (i.e., positive and/or negative) tones are prioritized over neutral ones at an early, perceptual stage of auditory processing. In order to avoid perceptual confounds, we induced valence experimentally during a learning phase by assigning positive, negative, and neutral valences to tone-frequencies in a balanced design. In a subsequent test phase, EEG was recorded while these tones were entirely task-irrelevant. The amplitude of the auditory N1 was increased for valenced compared with neutral tones, indicating enhanced attention. While behavioral results of the learning phase, and both implicit and explicit measures of tone evaluation indicated differentiation between positive and negative valence, there was no such differentiation on the N1 amplitude. Our results suggest that it is the general relevance of the valenced tones that governs early attentional processes.

Event-related potential signatures of perceived and imagined emotional and food real-life photos

Although food and affective pictures share similar emotional and motivational characteristics, the relationship between the neuronal responses to these stimuli is unclear. Particularly, it is not known whether perceiving and imagining food and affective stimuli elicit similar event-related potential (ERP) patterns. In this study, two ERP correlates, the early posterior negativity (EPN) and the late positive potential (LPP) for perceived and imagined emotional and food photographs were investigated. Thirteen healthy volunteers were exposed to a set of food photos, as well as unpleasant, pleasant, and neutral photos from the International Affective Picture System. In each trial, participants were first asked to view a photo (perception condition), and then to create a visual mental image of it and to rate its vividness (imagery condition). The results showed that during perception, brain regions corresponding to sensorimotor and parietal motivational (defensive and appetitive) systems were activated to different extents, producing a graded pattern of EPN and LPP responses specific to the photo content - more prominent for unpleasant than pleasant and food content. Also, an EPN signature occurred in both conditions for unpleasant content, suggesting that, compared to food or pleasant content, unpleasant content may be attended to more intensely during perception and may be represented more distinctly during imagery. Finally, compared to LLP activation during perception, as well as imagery and perception of all other content, LPP activation was significantly reduced during imagery of unpleasant photos, suggesting inhibition of unwanted memories. Results are framed within a neurocognitive working model of embodied emotions.

Higher, faster, worse? An event-related potentials study of affective picture processing in migraine

BACKGROUND

Migraine is a disorder of periodic disabling headache. Facilitated cortical responsivity has been suggested as one predisposing factor. Although the underlying mechanisms of migraine attack onsets are not fully understood, facilitated cortical responsivity has been suggested as one predisposing factor. Here, we investigate if enhanced cortical responsivity is reflected in altered event-related potentials during processing of complex pictures.

METHOD

Altogether, 16 migraine patients and 16 healthy volunteers participated in this study. Each patient had a diagnosed migraine and was headache- and medication-free for the study. Participants watched positive, negative and neutral pictures from the international affective picture system. An electroencephalogram was recorded during picture presentation. Afterwards, participants were asked to rate the pictures for valence and arousal.

RESULTS

Migraine patients showed significantly more negative-going early event-related potential components from 100 ms to 180 ms to all picture categories over occipital regions as well as more positive-going late potentials over central regions. Patients and controls did not differ in valence and arousal ratings for the international-affective picture system.

DISCUSSION

Patients with migraine seem to react cortically more intensely to all kinds of pictorial stimuli, regardless of emotional content. This facilitated processing may be related to the high cortical responsivity shown in various other event-related potential studies and might contribute to the recurring intense headache attacks.

Affective facilitation of early visual cortex during rapid picture presentation at 6 and 15 Hz

The steady-state visual evoked potential (SSVEP), a neurophysiological marker of attentional resource allocation with its generators in early visual cortex, exhibits enhanced amplitude for emotional compared to neutral complex pictures. Emotional cue extraction for complex images is linked to the N1-EPN complex with a peak latency of ∼140-160 ms. We tested whether neural facilitation in early visual cortex with affective pictures requires emotional cue extraction of individual images, even when a stream of images of the same valence category is presented. Images were shown at either 6 Hz (167 ms, allowing for extraction) or 15 Hz (67 ms per image, causing disruption of processing by the following image). Results showed SSVEP amplitude enhancement for emotional compared to neutral images at a presentation rate of 6 Hz but no differences at 15 Hz. This was not due to featural differences between the two valence categories. Results strongly suggest that individual images need to be displayed for sufficient time allowing for emotional cue extraction to drive affective neural modulation in early visual cortex.

Social and emotional relevance in face processing: happy faces of future interaction partners enhance the late positive potential

Human face perception is modulated by both emotional valence and social relevance, but their interaction has rarely been examined. Event-related brain potentials (ERP) to happy, neutral, and angry facial expressions with different degrees of social relevance were recorded. To implement a social anticipation task, relevance was manipulated by presenting faces of two specific actors as future interaction partners (socially relevant), whereas two other face actors remained non-relevant. In a further control task all stimuli were presented without specific relevance instructions (passive viewing). Face stimuli of four actors (2 women, from the KDEF) were randomly presented for 1s to 26 participants (16 female). Results showed an augmented N170, early posterior negativity (EPN), and late positive potential (LPP) for emotional in contrast to neutral facial expressions. Of particular interest, face processing varied as a function of experimental tasks. Whereas task effects were observed for P1 and EPN regardless of instructed relevance, LPP amplitudes were modulated by emotional facial expression and relevance manipulation. The LPP was specifically enhanced for happy facial expressions of the anticipated future interaction partners. This underscores that social relevance can impact face processing already at an early stage of visual processing. These findings are discussed within the framework of motivated attention and face processing theories.

Event-related brain potentials to emotional images and gonadal steroid hormone levels in patients with schizophrenia and paired controls

Prominent disturbances in the experience, expression, and emotion recognition in patients with schizophrenia have been relatively well documented over the last few years. Furthermore, sex differences in behavior and brain activity, associated with the processing of various emotions, have been reported in the general population and in schizophrenia patients. Others proposed that sex differences should be rather attributed to testosterone, which may play a role in the etiology of schizophrenia. Also, it had been suggested that estradiol may play a protective role in schizophrenia. Surprisingly, few studies investigating this pathology have focused on both brain substrates and gonadal steroid hormone levels, in emotional processing. In the present study, we investigated electrocortical responses related to emotional valence and arousal as well as gonadal steroid hormone levels in patients with schizophrenia. Event-Related Potentials (ERP) were recorded during exposition to emotional pictures in 18 patients with schizophrenia and in 24 control participants paired on intelligence, manual dominance and socioeconomic status. Given their previous sensitivity to emotional and attention processes, the P200, N200 and the P300 were selected for analysis. More precisely, emotional valence generally affects early components (N200), which reflect early process of selective attention, whereas emotional arousal and valence both influences the P300 component, which is related to memory context updating, and stimulus categorization. Results showed that, in the control group, the amplitude of the N200 was significantly more lateralized over the right hemisphere, while there was no such lateralization in patients with schizophrenia. In patients with schizophrenia, significantly smaller anterior P300 amplitude was observed to the unpleasant, compared to the pleasant. That anterior P300 reduction was also correlated with negative symptoms. The N200 and P300 amplitudes were positively correlated with the estradiol level in all conditions, revealing that the N200 and the P300 were reduced, when estradiol level was higher. Conversely, only the P300 amplitude showed positive correlation with the testosterone level.

Representations of modality-specific affective processing for visual and auditory stimuli derived from functional magnetic resonance imaging data

There is converging evidence that people rapidly and automatically encode affective dimensions of objects, events, and environments that they encounter in the normal course of their daily routines. An important research question is whether affective representations differ with sensory modality. This research examined the nature of the dependency of affect and sensory modality at a whole-brain level of analysis in an incidental affective processing paradigm. Participants were presented with picture and sound stimuli that differed in positive or negative valence in an event-related functional magnetic resonance imaging experiment. Global statistical tests, applied at a level of the individual, demonstrated significant sensitivity to valence within modality, but not valence across modalities. Modality-general and modality-specific valence hypotheses predict distinctly different multidimensional patterns of the stimulus conditions. Examination of lower dimensional representation of the data demonstrated separable dimensions for valence processing within each modality. These results provide support for modality-specific valence processing in an incidental affective processing paradigm at a whole-brain level of analysis. Future research should further investigate how stimulus-specific emotional decoding may be mediated by the physical properties of the stimuli.

Beyond pleasure and arousal: appetitive erotic stimuli modulate electrophysiological brain correlates of early attentional processing

Previous studies investigating affective reactions to pictures that elicit a specific effect have mainly focused on the dimensions valence and arousal. Using an event-related picture-viewing paradigm in electroencephalography, we investigated whether erotica - that is appetitive, evolutionarily relevant stimuli - have effects on early stages of attentional processing that are distinct from those of other positive and arousing stimuli. Seventeen male students viewed arousing photos of erotic, nude women or pictures of extreme sport scenes, as well as control pictures of attractive, dressed women or daily activities. Erotic pictures differed from extreme sport pictures not only in late but also in early attentional processes, as indicated by event-related potentials appearing from 130 ms after stimulus onset (P1). The findings suggest (a) that the dimension of appetence should be considered in addition to valence and arousal when investigating psychophysiological reactions to affective-motivational stimuli and (b) that early attentional processing as mirrored by the P1 can be influenced by motivational systems.

Early affective processing in patients with acute posttraumatic stress disorder: magnetoencephalographic correlates

Background

In chronic PTSD, a preattentive neural alarm system responds rapidly to emotional information, leading to increased prefrontal cortex (PFC) activation at early processing stages (<100 ms). Enhanced PFC responses are followed by a reduction in occipito-temporal activity during later processing stages. However, it remains unknown if this neuronal pattern is a result of a long lasting mental disorder or if it represents changes in brain function as direct consequences of severe trauma.

Methodology

The present study investigates early fear network activity in acutely traumatized patients with PTSD. It focuses on the question whether dysfunctions previously observed in chronic PTSD patients are already present shortly after trauma exposure. We recorded neuromagnetic activity towards emotional pictures in seven acutely traumatized PTSD patients between one and seven weeks after trauma exposure and compared brain responses to a balanced healthy control sample. Inverse modelling served for mapping sources of differential activation in the brain.

Principal Findings

Compared to the control group, acutely traumatized PTSD patients showed an enhanced PFC response to high-arousing pictures between 60 to 80 ms. This rapid prefrontal hypervigilance towards arousing pictorial stimuli was sustained during 120–300 ms, where it was accompanied by a reduced affective modulation of occipito-temporal neural processing.

Conclusions

Our findings indicate that the hypervigilance-avoidance pattern seen in chronic PTSD is not necessarily a product of an endured mental disorder, but arises as an almost immediate result of severe traumatisation. Thus, traumatic experiences can influence emotion processing strongly, leading to long-lasting changes in trauma network activation and expediting a chronic manifestation of maladaptive cognitive and behavioral symptoms.

How about lunch? Consequences of the meal context on cognition and emotion

Although research addresses the effects of a meal’s context on food preference, the psychological consequences of meal situations are largely unexplored. We compared the cognitive and emotional effects of a restaurant meal eaten in the company of others to a solitary meal consumed in a plain office using pre- and post-tests analysis and controlling for the kind and amount of food consumed. Three tasks were conducted, measuring: (1) semantic memory (2) cognitive control and error monitoring, and (3) processing of emotional facial expressions. Covert processes in these tasks were assessed with event-related brain potentials. A mood rating questionnaire indicated a relaxation effect of the restaurant as compared to the plain meal situation. The restaurant meal increased sensitivity to threatening facial expressions and diminished cognitive control and error monitoring. No effects were observed for semantic memory. These findings provide the first experimental evidence that a restaurant meal with a social component may be more relaxing than a meal eaten alone in a plain setting and may reduce cognitive control.

Reprint of "Affective picture processing as a function of preceding picture valence: an ERP analysis"

Event-related brain potential (ERP) studies consistently revealed that a relatively early (early posterior negativity; EPN) and a late (late positive potential; LPP) ERP component differentiate between emotional and neutral picture stimuli. Two studies examined the processing of emotional stimuli when preceded either by pleasant, neutral, or unpleasant context images. In both studies, distinct streams of six pictures were shown. In Study 1, hedonic context was alternated randomly across the 180 picture streams. In Study 2, hedonic context sequences were blocked, resulting in 60 preceding sequences of pleasant, neutral, and unpleasant context valence, respectively. The main finding was that the valence of the preceding picture sequence had no significant effect on the emotional modulation of the EPN and LPP components. However, previous results were replicated in that emotional stimulus processing was associated with larger EPN and LPP components as compared to neutral pictures. These findings suggest that the prioritized processing of emotional stimuli is primarily driven by the valence of the current picture.

Personality modulates the effects of emotional arousal and valence on brain activation

The influence of personality on the neural correlates of emotional processing is still not well characterized. We investigated the relationship between extraversion and neuroticism and emotional perception using functional magnetic resonance imaging (fMRI) in a group of 23 young, healthy women. Using a parametric modulation approach, we examined how the blood oxygenation level dependent (BOLD) signal varied with the participants' ratings of arousal and valence, and whether levels of extraversion and neuroticism were related to these modulations. In particular, we wished to test Eysenck's biological theory of personality, which links high extraversion to lower levels of reticulothalamic-cortical arousal, and neuroticism to increased reactivity of the limbic system and stronger reactions to emotional arousal. Individuals high in neuroticism demonstrated reduced sustained activation in the orbitofrontal cortex (OFC) and attenuated valence processing in the right temporal lobe while viewing emotional images, but an increased BOLD response to emotional arousal in the right medial prefrontal cortex (mPFC). These results support Eysenck's theory, as well as our hypothesis that high levels of neuroticism are associated with attenuated reward processing. Extraversion was inversely related to arousal processing in the right cerebellum, but positively associated with arousal processing in the right insula, indicating that the relationship between extraversion and arousal is not as simple as that proposed by Eysenck.