Emotionally positive stimuli facilitate lexical decisions—An ERP study

Thinking about it: the impact of COVID-19-related stimuli on prospective memory

Background

Since 2020, information regarding COVID-19 has been a constant presence in the news, in our conversations and thoughts. Continuous exposure to this type of stimuli could have an impact on cognitive processes essential for our everyday activities, such as prospective memory (PM). PM is the ability to remember to perform an intention at a specific point in the future, like remembering to take prescribed medicines at a specific time or to turn off the stove after cooking. Do COVID-related stimuli affect our ability to perform a PM task?

Methods

To answer this question, we proposed a novel version of the classical paradigm used to investigate PM. Namely, this paradigm includes a baseline condition, in which an ongoing task is presented alone, and a PM condition in which the same task is proposed again together with a second (prospective) task. In this study, a short video clip was presented between the baseline and the PM condition. The video clip displayed either neutral, negative, or COVID-related content. Additionally, participants were asked to respond to two questionnaires and a series of questions regarding their well-being and experience with the pandemic. Namely, the DASS-21 scale (evaluating depression, anxiety, and stress), and the COVID-19-PTSD questionnaire (a questionnaire evaluating post-traumatic stress disorder symptoms related to the pandemic experience) were administered. Participants' performance and responses were analyzed using a linear mixed effect (LME) model approach, and correlation analyses were run to highlight possible correlations between participants' scores in the DASS-21, the COVID-19-PTSD, and the additional questions on their personal experience with the pandemic.

Results

The LME models revealed significant effects of the displayed video on performance: in line with previous studies, the clip displaying standard negative contents led to impaired accuracy in the ongoing task in the PM condition, compared to the Baseline. In contrast, participants who saw the COVID-related clip showed improved accuracy in the ongoing task compared to the other participants, selectively in the block performed after the video clip was displayed (PM condition). Furthermore, the explanatory power of the LME model calculated on accuracy to the ongoing trials was enhanced by the inclusion of the scores in the anxiety subscale of the DASS-21, suggesting a detrimental role of anxiety. Altogether, these results indicate a different effect of the exposure to classical negative contents (associated with a cost in terms of accuracy in the ongoing task between the baseline and the PM condition) and the pandemic-related one, which was instead characterized by a higher accuracy to ongoing trials compared to the other video clips. This counterintuitive finding seems to suggest that COVID-related stimuli are processed as "acute stressors" rather than negative stimuli, thus inducing a state of increased alertness and responsivity.

Electrophysiological correlates of semantic pain processing in the affective priming

Introduction

Pain plays a fundamental role in the well-being of the individual, and its semantic content may have specific properties compared to other negative domains (i.e., fear and anger) which allows the cognitive system to detect it with priority. Considering the influence of the affective context in which stimuli (targets) are evaluated, it is possible that their valence could be differentially processed if preceded by negative stimuli (primes) associated with pain than negative stimuli not associated with pain. Thus, the present study aims to investigate the electrophysiological correlates of the implicit processing of words with pain content by using an affective priming paradigm.

Methods

Event-related potentials (ERPs) were recorded while participants were presented with positive and negative word targets (not associated with pain) that were preceded by positive, negative (not associated with pain), and pain word primes. Participants were asked to judge the valence of the target word.

Results

Results showed faster reaction times (RTs) in congruent conditions, especially when the negative target was preceded by a pain prime rather than a positive one. ERPs analyses showed no effect of pain at an early-stage processing (N400), but a larger waveform when the pain prime preceded the positive prime on the LPP.

Discussion

These results reaffirm the importance that valence has in establishing the priority with which stimuli are encoded in the environment and highlight the role that pain has in the processing of stimuli, supporting the hypothesis according to which the valence and the semantics of a stimulus interact with each other generating a specific response for each type of emotion.

The Effect of Exercise Intensity on Affective and Repetition Priming in Middle-Aged Adults

Previous research has shown that physical exercise improves memory. In the present study, we investigated the possible effects of the intensity of physical exercise as a function of the affective valence of words on implicit memory. In the study, 79 young adult volunteers were randomly assigned to perform moderate- (50% VO₂max) or high-intensity exercise (80% VO₂max) on a stationary bike. Once the required exercise intensity was achieved, participants performed an affective and repetition priming task concurrently with the physical exercise. Both groups showed similar repetition priming. The moderate-intensity exercise group showed affective priming with positive words, while affective priming was not found in the high-intensity exercise group. Facilitation occurred in both groups when a negative target word was preceded by a positive prime word. Our results suggest that the positive effect of physical exercise on memory is modulated by the affective valence of the stimuli. It seems that moderate-intensity exercise is more beneficial for implicit memory than high-intensity exercise.

The role of valence in word processing: Evidence from lexical decision and emotional Stroop tasks

It is widely accepted that the valence of a word (neutral, positive, or negative) influences lexical processing, yet data from the commonly used lexical decision and emotional Stroop tasks has yielded inconsistent findings regarding the direction of this influence. One critical obstacle to investigating the independent effects of valence is the matching of emotional and neutral stimuli on the lexical, sublexical, and conceptual characteristics known to influence word recognition. The second obstacle is that the cognitive processes which lead to a lexical decision and a colour naming response are unobservable from the response latency measures typically gathered. The present study compiled a set of neutral, positive, and negative words matched triplet-wise on 26 influential characteristics. The novel "mouse tracking" technique was used to analyse the development of responses to these materials in variants of the lexical decision and emotional Stroop task. A conventional key-press emotional Stroop task is also reported. Results revealed a significant processing advantage for positive words over negative and neutral words in the lexical decision task, whereas valence alone did not produce any significant effects in the emotional Stroop task. The discrepancy between the effects of valence across these different tasks is discussed. We also suggest that previous conflicting findings may be confounded by unmatched emotional and neutral stimuli, thus inflating the potential effects of valence.

Neural correlates of affective contributions to lexical decisions in children and adults

The goal of the present study was to investigate whether 6-9-year old children and adults show similar neural responses to affective words. An event-related neuroimaging paradigm was used in which both age cohorts performed the same auditory lexical decision task (LDT). The results show similarities in (auditory) lexico-semantic network activation as well as in areas associated with affective information. In both age cohorts' activations were stronger for positive than for negative words, thus exhibiting a positivity superiority effect. Children showed less activation in areas associated with affective information in response to all three valence categories than adults. Our results are discussed in the light of computational models of word recognition, and previous findings of affective contributions to LDT in adults.

Transcutaneous Vagus Nerve Stimulation (tVNS) Improves High-Confidence Recognition Memory but Not Emotional Word Processing

Previous clinical research found that invasive vagus nerve stimulation (VNS) enhanced word recognition memory in epileptic patients, an effect assumed to be related to the activation of brainstem arousal systems. In this study, we applied non-invasive transcutaneous auricular VNS (tVNS) to replicate and extend the previous work. Using a single-blind, randomized, between-subject design, 60 healthy volunteers received active or sham stimulation during a lexical decision task, in which emotional and neutral stimuli were classified as words or non-words. In a subsequent recognition memory task (1 day after stimulation), participants' memory performance on these words and their subjective memory confidence were tested. Salivary alpha-amylase (sAA) levels, a putative indirect measure of central noradrenergic activation, were also measured before and after stimulation. During encoding, pleasant words were more accurately detected than neutral and unpleasant words. However, no tVNS effects were observed on task performance or on overall sAA level changes. tVNS also did not modulate overall recognition memory, which was particularly enhanced for pleasant emotional words. However, when hit rates were split based on confidence ratings reflecting familiarity- and recollection-based memory, higher recollection-based memory performance (irrespective of emotional category) was observed during active stimulation than during sham stimulation. To summarize, we replicated prior findings of enhanced processing and memory for emotional (pleasant) words. Whereas tVNS showed no effects on word processing, subtle effects on recollection-based memory performance emerged, which may indicate that tVNS facilitates hippocampus-mediated consolidation processes.

ERP and oscillatory differences in overweight/obese and normal-weight adolescents in response to food stimuli

BACKGROUND

Findings are mixed regarding the association of electroencephalographic (EEG) attentional bias measures and body weight, with few studies measuring food craving or intake and no study reporting oscillatory measures.

METHODS

EEG data were collected while 28 satiated adolescents (14 overweight/obese) viewed pictures of neutral, low-calorie food, and high-calorie food stimuli and rated their desire to eat, before having access to high-calorie snacks.

RESULTS

Unlike normal-weight adolescents, overweight/obese participants showed similar P300 amplitudes for high- and low-calorie food, and strongest event-related alpha band desynchronization for low-calorie stimuli. P300 amplitudes and state craving for low-calorie food furthermore predicted snack intake in this group.

CONCLUSIONS

The current research focus in overweight/obesity might need to be extended to include low-calorie food. While all participants showed an attentional bias for high-calorie food, it was the processing of low-calorie food which distinguished the two weight groups on measures of neural activity and which was associated with snack food intake in the overweight/obese group.

Deep Brain Stimulation of the Subthalamic Nucleus Influences Facial Emotion Recognition in Patients With Parkinson's Disease: A Review

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by motor symptoms following dopaminergic depletion in the substantia nigra. Besides motor impairments, however, several non-motor detriments can have the potential to considerably impact subjectively perceived quality of life in patients. Particularly emotion recognition of facial expressions has been shown to be affected in PD, and especially the perception of negative emotions like fear, anger, or disgust is impaired. While emotion processing generally refers to automatic implicit as well as conscious explicit processing, the focus of most previous studies in PD was on explicit recognition of emotions only, while largely ignoring implicit processing deficits. Deep brain stimulation of the subthalamic nucleus (STN-DBS) is widely accepted as a therapeutic measure in the treatment of PD and has been shown to advantageously influence motor problems. Among various concomitant non-motor effects of STN-DBS, modulation of facial emotion recognition under subthalamic stimulation has been investigated in previous studies with rather heterogeneous results. Although there seems to be a consensus regarding the processing of disgust, which significantly deteriorates under STN stimulation, findings concerning emotions like fear or happiness report heterogeneous data and seem to depend on various experimental settings and measurements. In the present review, we summarized previous investigations focusing on STN-DBS influence on recognition of facial emotional expressions in patients suffering from PD. In a first step, we provide a synopsis of disturbances and problems in facial emotion processing observed in patients with PD. Second, we present findings of STN-DBS influence on facial emotion recognition and especially highlight different impacts of stimulation on implicit and explicit emotional processing.

Valence makes a stronger contribution than arousal to affective priming

BACKGROUND

Recent data suggest that both word valence and arousal modulate subsequent cognitive processing. However, whether valence or arousal makes a stronger contribution to cognitive processing is less understood.

METHODS

The present study performed three experiments that varied the valence (positive or negative) and arousal (high or low) of prime-target word pairs in a lexical decision-priming task. Affective priming was derived from pure valence (Experiment 1), pure arousal (Experiment 2), or a combination of valence and arousal (Experiment 3).

RESULTS

By comparing three types of priming effects, we found an effect of valence on affective priming was obvious regardless of whether the relationship of the prime-target varied with valence, arousal, or the combination of valence and arousal. In contrast, an effect of arousal on affective priming only appeared in the condition that based on the arousal relationship of the prime-target pair. Moreover, the valence-driven priming effect, arousal-driven priming effect, and emotional-driven priming effect were modulated by valence type but not by arousal level of word stimuli.

CONCLUSION

The present results revealed a pattern of valence and arousal in semantic networks, indicating that the valence information of emotional words tends to be more stable than arousal information within the semantic system, at least in the present lexical decision-priming task.

Deep Brain Stimulation of the Subthalamic Nucleus Selectively Modulates Emotion Recognition of Facial Stimuli in Parkinson's Patients

: Background: Diminished emotion recognition is a known symptom in Parkinson (PD) patients and subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to further deteriorate the processing of especially negative emotions. While emotion recognition generally refers to both, implicit and explicit processing, demonstrations of DBS-influences on implicit processing are sparse. In the present study, we assessed the impact of STN-DBS on explicit and implicit processing for emotional stimuli.

METHODS

Under STN-DBS ON and OFF, fourteen PD patients performed an implicit as well as an explicit emotional processing task. To assess implicit emotional processing, patients were tested with a lexical decision task (LTD) combined with an affective priming paradigm, which provides emotional content through the facial eye region. To assess explicit emotional processing, patients additionally explicitly rated the emotional status of eyes and words used in the implicit task.

RESULTS

DBS affected explicit emotional processing more than implicit processing with a more pronounced effect on error rates than on reaction speed. STN-DBS generally worsened implicit and explicit processing for disgust stimulus material but improved explicit processing of fear stimuli.

CONCLUSIONS

This is the first study demonstrating influences of STN-DBS on explicit and implicit emotion processing in PD patients. While STN stimulation impeded the processing of disgust stimuli, it improved explicit discrimination of fear stimuli.

Independent ERP predictors of affective priming underline the importance of depth of prime and target processing and implicit affect misattribution

We used event-related potentials (ERPs) to investigate the mental processes that contribute to affective priming (AP), a systematic shift of evaluative judgments about neutral targets toward the valence of preceding primes. 64 participants rated their liking of a priori neutral ideographs preceded by 800-ms emotional primewords, while 64-channel EEG was recorded. We observed a significant AP effect that was closely associated with prime valence dependent variations of the right central-to-parieto-occipital positive slow wave (PSW) amplitude in the target ERP, providing evidence for implicit affect misattribution as one source of the effect. While deeper target processing mirrored in valence unspecific central-to-parieto-occipital target PSW amplitude was negatively associated with AP, deeper prime processing indicated by valence unspecific central-to-parieto-occipital prime PSW amplitude was positively related to AP. These depth of processing effects underline the importance of strategic processes in AP. In a stepwise linear regression analysis, the prime valence effect on right central-to-parieto-occipital target PSW indicating affect misattribution and the two valence-unspecific ERP indices of processing depth (central-to-parieto-occipital prime- and target PSW) were independent predictors of the size of the AP effect. Together they accounted for 60% of the variance. Furthermore, an explorative analysis provided first evidence for the relevance of early discrimination of prime valence for AP.

Does it matter if we approach or withdraw when reading? A comparison of fear-related words and anger-related words

The main aim of the present research was to explore the role of affective features beyond valence and arousal (i.e., the approach-withdrawal dimension) in visual word processing. For this purpose, fear-related words and anger-related words were compared in three tasks: a lexical decision task (LDT), a valence decision task (VDT) and an approach-distancing decision task (ADDT). Although these two types of words did not differ in the first two tasks, faster 'distancing' responses were given to anger-related words than to fear-related words in the ADDT. As long as these two types of words were matched in valence and arousal (among other variables), these results illustrate the need to consider other emotional dimensions (in this case, the approach-withdrawal dimension) beyond the two-dimensional perspective in order to account for the emotional effects in visual words processing and to describe how the affective space is organized. In addition, the results suggest a task-dependence effect: differential effects of fear and anger only emerged when participants were explicitly focused on the approach-withdrawal dimension. These findings are discussed in relation to motivationally-based mechanisms.

Effects of valence and arousal on affective priming vary with the degree of affective experience denoted by words

We investigated whether the effect of the valence and arousal of less or more affective experiential words on affective priming using event-related potentials (ERPs). The stimuli included less affective experiential (LE) words (Experiment 1) and more affective experiential (ME) words (Experiment 2) that were organized in an orthogonal design, with valence (positive and negative) and arousal (low and high) as factors in a lexical decision task. In Experiment 1, the results revealed no obvious effect of affective priming on response times (RTs) or ERPs for LE words. In Experiment 2, affective priming effects of ME words were influenced interactively by valence and arousal. Specifically, for positive ME words with high- and low-arousal, affectively incongruent trials were associated with longer RTs and enhanced late positive components (LPCs, 430-700 ms) compared with congruent trials (a positive effect). For negative ME words with low-arousal, no significant differences in RTs or LPC amplitudes were found between affectively congruent and incongruent trials (a null effect), whereas for negative ME words with high-arousal, the processing of congruent trials was associated with longer RTs and enhanced LPC amplitudes over that of incongruent trials (a reversal effect). On the one hand, our findings suggest that LE and ME words as primes produce different effects on the processing of subsequently presented targets. On the other hand, our findings further indicate that there seems to have a continuous transition from the spreading activation of ME words to an inhibition process in semantic memory along with their valence and arousal, which is involved in decision-making processes and memory-related stages.

"Passion" versus "patience": the effects of valence and arousal on constructive word recognition

Accumulating evidence suggests that emotional information is often recognised faster than neutral information. Several studies examined the effects of valence and arousal on word recognition, but yielded partially diverging results. Here, we used two alternative versions of a constructive recognition paradigm in which a target word is hidden by a visual mask that gradually disappears, to investigate whether the emotional properties of words influence their speed of recognition. Participants were instructed either to classify the incrementally appearing word as emotional or non-emotional (semantic categorisation task) or to decide whether the appearing letter string is an existing word or not (lexical decision task). Results from both tasks revealed faster recognition times for high- compared to low-arousing words, and for positive compared to negative or neutral words. These findings indicate a recognition advantage for emotionally positive and highly arousing stimuli that persists even when visual word recognition is hampered and participants are encouraged to make more active, semantic inferences to generate the meaning of the emerging word.

Neural Correlates of Emotion Processing in Word Detection Task

In our previous study, we have proposed a three-stage model of emotion processing; in the current study, we investigated whether the ERP component may be different when the emotional content of stimuli is task-irrelevant. In this study, a dual-target rapid serial visual presentation (RSVP) task was used to investigate how the emotional content of words modulates the time course of neural dynamics. Participants performed the task in which affectively positive, negative, and neutral adjectives were rapidly presented while event-related potentials (ERPs) were recorded from 18 undergraduates. The N170 component was enhanced for negative words relative to positive and neutral words. This indicates that automatic processing of negative information occurred at an early perceptual processing stage. In addition, later brain potentials such as the late positive potential (LPP) were only enhanced for positive words in the 480-580-ms post-stimulus window, while a relatively large amplitude signal was elicited by positive and negative words between 580 and 680 ms. These results indicate that different types of emotional content are processed distinctly at different time windows of the LPP, which is in contrast with the results of studies on task-relevant emotional processing. More generally, these findings suggest that a negativity bias to negative words remains to be found in emotion-irrelevant tasks, and that the LPP component reflects dynamic separation of emotion valence.

Moved by words: Affective ratings for a set of 2,266 Spanish words in five discrete emotion categories

The two main theoretical accounts of the human affective space are the dimensional perspective and the discrete-emotion approach. In recent years, several affective norms have been developed from a dimensional perspective, including ratings for valence and arousal. In contrast, the number of published datasets relying on the discrete-emotion approach is much lower. There is a need to fill this gap, considering that discrete emotions have an effect on word processing above and beyond those of valence and arousal. In the present study, we present ratings from 1,380 participants for a set of 2,266 Spanish words in five discrete emotion categories: happiness, anger, fear, disgust, and sadness. This will be the largest dataset published to date containing ratings for discrete emotions. We also present, for the first time, a fine-grained analysis of the distribution of words into the five emotion categories. This analysis reveals that happiness words are the most consistently related to a single, discrete emotion category. In contrast, there is a tendency for many negative words to belong to more than one discrete emotion. The only exception is disgust words, which overlap least with the other negative emotions. Normative valence and arousal data already exist for all of the words included in this corpus. Thus, the present database will allow researchers to design studies to contrast the predictions of the two most influential theoretical perspectives in this field. These studies will undoubtedly contribute to a deeper understanding of the effects of emotion on word processing.

Effects of Valence on Hemispheric Specialization for Emotion Word Processing

The use of emotion in language is a key element of human interactions and a rich area for cognitive research. The present study examined reactions to words of five types: positive emotion (e.g., happiness), negative emotion (e.g., hatred), positive emotion-laden (e.g., blessing), negative emotion-laden (e.g., prison), and neutral (e.g., chance). Words and nonwords were intermixed in a lexical decision task using hemifield presentation. Results revealed a general left hemisphere advantage. Overall, reaction times for positive words were faster than for negative or neutral words and this effect varied by hemifield of presentation. These results support a valence hypothesis of specialized processing in the left hemisphere of the brain for positive emotions and the right hemisphere for negative emotions.

Vivid: How valence and arousal influence word processing under different task demands

In this study, we used event-related potentials to examine how different dimensions of emotion-valence and arousal-influence different stages of word processing under different task demands. In two experiments, two groups of participants viewed the same single emotional and neutral words while carrying out different tasks. In both experiments, valence (pleasant, unpleasant, and neutral) was fully crossed with arousal (high and low). We found that the task made a substantial contribution to how valence and arousal modulated the late positive complex (LPC), which is thought to reflect sustained evaluative processing (particularly of emotional stimuli). When participants performed a semantic categorization task in which emotion was not directly relevant to task performance, the LPC showed a larger amplitude for high-arousal than for low-arousal words, but no effect of valence. In contrast, when participants performed an overt valence categorization task, the LPC showed a large effect of valence (with unpleasant words eliciting the largest positivity), but no effect of arousal. These data show not only that valence and arousal act independently to influence word processing, but that their relative contributions to prolonged evaluative neural processes are strongly influenced by the situational demands (and by individual differences, as revealed in a subsequent analysis of subjective judgments).

Temporal orienting precedes intersensory attention and has opposing effects on early evoked brain activity

Intersensory attention (IA) describes the process of directing attention to a specific modality. Temporal orienting (TO) characterizes directing attention to a specific moment in time. Previously, studies indicated that these two processes could have opposite effects on early evoked brain activity. The exact time-course and processing stages of both processes are still unknown. In this human electroencephalography study, we investigated the effects of IA and TO on visuo-tactile stimulus processing within one paradigm. IA was manipulated by presenting auditory cues to indicate whether participants should detect visual or tactile targets in visuo-tactile stimuli. TO was manipulated by presenting stimuli block-wise at fixed or variable inter-stimulus intervals. We observed that TO affects evoked activity to visuo-tactile stimuli prior to IA. Moreover, we found that TO reduces the amplitude of early evoked brain activity, whereas IA enhances it. Using beamformer source-localization, we observed that IA increases neural responses in sensory areas of the attended modality whereas TO reduces brain activity in widespread cortical areas. Based on these findings we derive an updated working model for the effects of temporal and intersensory attention on early evoked brain activity.

Affective Priming by Eye Gaze Stimuli: Behavioral and Electrophysiological Evidence

The present study employed the affective priming paradigm and measurements of event-related potentials (ERPs) to investigate implicit affective reactions elicited by gaze stimuli. Participants categorized positive and negative words primed by direct gaze, averted gaze and closed eyes. The behavioral response time (RT) results indicated that direct gaze implicitly elicited more positive affective reactions than did closed eyes. Analyses of the ERP responses to the target words revealed a priming effect on the N170 and an interaction on late positive potential (LPP) responses, and congruently with the behavioral results, suggested that, compared to closed eyes, direct gaze was affectively more congruent with positive words and more incongruent with negative words. The priming effect on the N170 response indicated that gaze stimuli influenced the subsequent affective word processing at an early stage of information processing. In conclusion, the present behavioral and electrophysiological evidence suggests that direct gaze automatically activates more positive affective reactions than closed eyes.

Comparison of affective and semantic priming in different SOA

Researchers have been at odds on whether affective or semantic priming is faster or stronger. The present study selects a series of facial expression photos and words, which have definite emotional meaning or gender meaning, to set up experiment including both affective and semantic priming. The intensity of emotion and gender information in the prime as well as the strength of emotional or semantic (in gender) relationship between the prime and the target is matched. Three groups of participants are employed separately in our experiment varied with stimulus onset asynchrony (SOA) as 50, 250 or 500 ms. The results show that the difference between two types of priming effect is revealed when the SOA is at 50 ms, in which the affective priming effect is presented when the prime has negative emotion. It indicates that SOA can affect the comparison between the affective and semantic priming, and the former takes the priority in the automatic processing level.

Effects of valence and arousal on emotional word processing are modulated by concreteness: Behavioral and ERP evidence from a lexical decision task

We investigated whether the effects of valence and arousal on emotional word processing are modulated by concreteness using event-related potentials (ERPs). The stimuli included concrete words (Experiment 1) and abstract words (Experiment 2) that were organized in an orthogonal design, with valence (positive and negative) and arousal (low and high) as factors in a lexical decision task. In Experiment 1, the impact of emotion on the effects of concrete words mainly resulted from the contribution of valence. Positive concrete words were processed more quickly than negative words and elicited a reduction of N400 (300-410ms) and enhancement of late positive complex (LPC; 450-750ms), whereas no differences in response times or ERPs were found between high and low levels of arousal. In Experiment 2, the interaction between valence and arousal influenced the impact of emotion on the effects of abstract words. Low-arousal positive words were associated with shorter response times and a reduction of LPC amplitudes compared with high-arousal positive words. Low-arousal negative words were processed more slowly and elicited a reduction of N170 (140-200ms) compared with high-arousal negative words. The present study indicates that word concreteness modulates the contributions of valence and arousal to the effects of emotion, and this modulation occurs during the early perceptual processing stage (N170) and late elaborate processing stage (LPC) for emotional words and at the end of all cognitive processes (i.e., reflected by response times). These findings support an embodied theory of semantic representation and help clarify prior inconsistent findings regarding the ways in which valance and arousal influence different stages of word processing, at least in a lexical decision task.

Reduced frontal theta oscillations indicate altered crossmodal prediction error processing in schizophrenia

Our brain generates predictions about forthcoming stimuli and compares predicted with incoming input. Failures in predicting events might contribute to hallucinations and delusions in schizophrenia (SZ). When a stimulus violates prediction, neural activity that reflects prediction error (PE) processing is found. While PE processing deficits have been reported in unisensory paradigms, it is unknown whether SZ patients (SZP) show altered crossmodal PE processing. We measured high-density electroencephalography and applied source estimation approaches to investigate crossmodal PE processing generated by audiovisual speech. In SZP and healthy control participants (HC), we used an established paradigm in which high- and low-predictive visual syllables were paired with congruent or incongruent auditory syllables. We examined crossmodal PE processing in SZP and HC by comparing differences in event-related potentials and neural oscillations between incongruent and congruent high- and low-predictive audiovisual syllables. In both groups event-related potentials between 206 and 250 ms were larger in high- compared with low-predictive syllables, suggesting intact audiovisual incongruence detection in the auditory cortex of SZP. The analysis of oscillatory responses revealed theta-band (4-7 Hz) power enhancement in high- compared with low-predictive syllables between 230 and 370 ms in the frontal cortex of HC but not SZP. Thus aberrant frontal theta-band oscillations reflect crossmodal PE processing deficits in SZ. The present study suggests a top-down multisensory processing deficit and highlights the role of dysfunctional frontal oscillations for the SZ psychopathology.

Affective Priming by Simple Geometric Shapes: Evidence from Event-related Brain Potentials

Previous work has demonstrated that simple geometric shapes may convey emotional meaning using various experimental paradigms. However, whether affective meaning of simple geometric shapes can be automatically activated and influence the evaluations of subsequent stimulus is still unclear. Thus the present study employed an affective priming paradigm to investigate whether and how two geometric shapes (circle vs. downward triangle) impact on the affective processing of subsequently presented faces (Experiment 1) and words (Experiment 2). At behavioral level, no significant effect of affective congruency was found. However, ERP results in Experiment 1 and 2 showed a typical effect of affective congruency. The LPP elicited by affectively incongruent trials was larger compared to congruent trials. Our results provide support for the notion that downward triangle is perceived as negative and circle as positive and their emotional meaning can be activated automatically and then exert an influence on the electrophysiological processing of subsequent stimuli. The lack of significant congruent effect in behavioral measures and the inversed N400 congruent effect might reveal that the affective meaning of geometric shapes is weak because they are just abstract threatening cues rather than real threat. In addition, because no male participants are included in the present study, our findings are limited to females.

From Memory to Attitude: The Neurocognitive Process beyond Euthanasia Acceptance

Numerous questionnaire studies on attitudes towards euthanasia produced conflicting results, precluding any general conclusion. This might be due to the fact that human behavior can be influenced by automatically triggered attitudes, which represent ingrained associations in memory and cannot be assessed by standard questionnaires, but require indirect measures such as reaction times (RT) or electroencephalographic recording (EEG). Event related potentials (ERPs) of the EEG and RT during an affective priming task were assessed to investigate the impact of automatically triggered attitudes and were compared to results of an explicit questionnaire. Explicit attitudes were ambivalent. Reaction time data showed neither positive nor negative associations towards euthanasia. ERP analyses revealed an N400 priming effect with lower mean amplitudes when euthanasia was associated with negative words. The euthanasia-related modulation of the N400 component shows an integration of the euthanasia object in negatively valenced associative neural networks. The integration of all measures suggests a bottom-up process of attitude activation, where automatically triggered negative euthanasia-relevant associations can become more ambiguous with increasing time in order to regulate the bias arising from automatic processes. These data suggest that implicit measures may make an important contribution to the understanding of euthanasia-related attitudes.

Emotional connotations of words related to authority and community

We present a database of 858 German words from the semantic fields of authority and community, which represent core dimensions of human sociality. The words were selected on the basis of co-occurrence profiles of representative keywords for these semantic fields. All words were rated along five dimensions, each measured by a bipolar semantic-differential scale: Besides the classic dimensions of affective meaning (valence, arousal, and potency), we collected ratings of authority and community with newly developed scales. The results from cluster, correlational, and multiple regression analyses on the rating data suggest a robust negativity bias for authority valuation among German raters recruited via university mailing lists, whereas community ratings appear to be rather unrelated to the well-established affective dimensions. Furthermore, our data involve a strong overall negative correlation-rather than the classical U-shaped distribution-between valence and arousal for socially relevant concepts. Our database provides a valuable resource for research questions at the intersection of cognitive neuroscience and social psychology. It can be downloaded as supplemental materials with this article.

Alpha-Band Oscillations Reflect Altered Multisensory Processing of the McGurk Illusion in Schizophrenia

The formation of coherent multisensory percepts requires integration of stimuli across the multiple senses. Patients with schizophrenia (ScZ) often experience a loss of coherent perception and hence, they might also show dysfunctional multisensory processing. In this high-density electroencephalography study, we investigated the neural signatures of the McGurk illusion, as a phenomenon of speech-specific multisensory processing. In the McGurk illusion lip movements are paired with incongruent auditory syllables, which can induce a fused percept. In ScZ patients and healthy controls we compared neural oscillations and event-related potentials (ERPs) to congruent audiovisual speech stimuli and McGurk illusion trials, where a visual /ga/ and an auditory /pa/ was often perceived as /ka/. There were no significant group differences in illusion rates. The EEG data analysis revealed larger short latency ERPs to McGurk illusion compared with congruent trials in controls. The reversed effect pattern was found in ScZ patients, indicating an early audiovisual processing deficit. Moreover, we observed stronger suppression of medio-central alpha-band power (8-10 Hz, 550-700 ms) in response to McGurk illusion compared with control trials in the control group. Again, the reversed pattern was found in SCZ patients. Moreover, within groups, alpha-band suppression was negatively correlated with the McGurk illusion rate in ScZ patients, while the correlation tended to be positive in controls. The topography of alpha-band effects indicated an involvement of auditory and/or frontal structures. Our study suggests that short latency ERPs and long latency alpha-band oscillations reflect abnormal multisensory processing of the McGurk illusion in ScZ.

When Feelings Arise with Meanings: How Emotion and Meaning of a Native Language Affect Second Language Processing in Adult Learners

To determine when and how L2 learners start to process L2 words affectively and semantically, we conducted a longitudinal study on their interaction in adult L2 learners. In four test sessions, spanning half a year of L2 learning, we monitored behavioral and ERP learning-related changes for one and the same set of words by means of a primed lexical-decision paradigm with L1 primes and L2 targets. Sensitivity rates, accuracy rates, RTs, and N400 amplitude to L2 words and pseudowords improved significantly across sessions. A semantic priming effect (e.g, prime "driver"facilitating response to target "street") was found in accuracy rates and RTs when collapsing Sessions 1 to 4, while this effect modulated ERP amplitudes within the first 300 ms of L2 target processing. An overall affective priming effect (e.g., "sweet" facilitating"taste") was also found in RTs and ERPs (posterior P1). Importantly, the ERPs showed an L2 valence effect across sessions (e.g., positive words were easier to process than neutral words), indicating that L2 learners were sensitive to L2 affective meaning. Semantic and affective priming interacted in the N400 time-window only in Session 4, implying that they affected meaning integration during L2 immersion together. The results suggest that L1 and L2 are initially processed semantically and affectively via relatively separate channels that are more and more linked contingent on L2 exposure.

Processing of emotion words by patients with autism spectrum disorders: evidence from reaction times and EEG

This study investigated processing of emotion words in autism spectrum disorders (ASD) using reaction times and event-related potentials (ERP). Adults with (n = 21) and without (n = 20) ASD performed a lexical decision task on emotion and neutral words while their brain activity was recorded. Both groups showed faster responses to emotion words compared to neutral, suggesting intact early processing of emotion in ASD. In the ERPs, the control group showed a typical late positive component (LPC) at 400-600 ms for emotion words compared to neutral, while the ASD group showed no LPC. The between-group difference in LPC amplitude was significant, suggesting that emotion words were processed differently by individuals with ASD, although their behavioral performance was similar to that of typical individuals.

Processing emotional words in two languages with one brain: ERP and fMRI evidence from Chinese-English bilinguals

Emotional words in a bilingual's second language (L2) seem to have less emotional impact compared to emotional words in the first language (L1). The present study examined the neural mechanisms of emotional word processing in Chinese-English bilinguals' two languages by using both event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI). Behavioral results show a robust positive word processing advantage in L1 such that responses to positive words were faster and more accurate compared to responses to neutral words and negative words. In L2, emotional words only received higher accuracies than neutral words. In ERPs, positive words elicited a larger early posterior negativity and a smaller late positive component than neutral words in L1, while a trend of reduced N400 component was found for positive words compared to neutral words in L2. In fMRI, reduced activation was found for L1 emotional words in both the left middle occipital gyrus and the left cerebellum whereas increased activation in the left cerebellum was found for L2 emotional words. Altogether, these results suggest that emotional word processing advantage in L1 relies on rapid and automatic attention capture while facilitated semantic retrieval might help processing emotional words in L2.

Neural correlates of an early attentional capture by positive distractor words

Exogenous or automatic attention to emotional distractors has been observed for emotional scenes and faces. In the language domain, however, automatic attention capture by emotional words has been scarcely investigated. In the current event-related potentials study we explored distractor effects elicited by positive, negative and neutral words in a concurrent but distinct target distractor paradigm. Specifically, participants performed a digit categorization task in which task-irrelevant words were flanked by numbers. The results of both temporo-spatial principal component and source location analyses revealed the existence of early distractor effects that were specifically triggered by positive words. At the scalp level, task-irrelevant positive compared to neutral and negative words elicited larger amplitudes in an anterior negative component that peaked around 120 ms. Also, at the voxel level, positive distractor words increased activity in orbitofrontal regions compared to negative words. These results suggest that positive distractor words quickly and automatically capture attentional resources diverting them from the task where attention was voluntarily directed.

Hemispheric asymmetry of emotion words in a non-native mind: a divided visual field study

This study investigates hemispheric specialization for emotional words among proficient non-native speakers of English by means of the divided visual field paradigm. The motivation behind the study is to extend the monolingual hemifield research to the non-native context and see how emotion words are processed in a non-native mind. Sixty eight females participated in the study, all highly proficient in English. The stimuli comprised 12 positive nouns, 12 negative nouns, 12 non-emotional nouns and 36 pseudo-words. To examine the lateralization of emotion, stimuli were presented unilaterally in a random fashion for 180 ms in a go/no-go lexical decision task. The perceptual data showed a right hemispheric advantage for processing speed of negative words and a complementary role of the two hemispheres in the recognition accuracy of experimental stimuli. The data indicate that processing of emotion words in non-native language may require greater interhemispheric communication, but at the same time demonstrates a specific role of the right hemisphere in the processing of negative relative to positive valence. The results of the study are discussed in light of the methodological inconsistencies in the hemifield research as well as the non-native context in which the study was conducted.

Seeing emotions in the eyes - inverse priming effects induced by eyes expressing mental states

Objective: Automatic emotional processing of faces and facial expressions gain more and more of relevance in terms of social communication. Among a variety of different primes, targets and tasks, whole face images and facial expressions have been used to affectively prime emotional responses. This study investigates whether emotional information provided solely in eye regions that display mental states can also trigger affective priming.

Methods: Sixteen subjects answered a lexical decision task (LDT) coupled with an affective priming paradigm. Emotion-associated eye regions were extracted from photographs of faces and acted as primes, whereas targets were either words or pseudo-words. Participants had to decide whether the targets were real German words or generated pseudo-words. Primes and targets belonged to the emotional categories “fear,” “disgust,” “happiness,” and “neutral.”

Results: A general valence effect for positive words was observed: responses in the LDT were faster for target words of the emotional category happiness when compared to other categories. Importantly, pictures of emotional eye regions preceding the target words affected their subsequent classification. While we show a classical priming effect for neutral target words – with shorter RT for congruent compared to incongruent prime-target pairs- , we observed an inverse priming effect for fearful and happy target words – with shorter RT for incongruent compared to congruent prime-target pairs. These inverse priming effects were driven exclusively by specific prime-target pairs.

Conclusion: Reduced facial emotional information is sufficient to induce automatic implicit emotional processing. The emotional-associated eye regions were processed with respect to their emotional valence and affected the performance on the LDT.

Friendly drug-dealers and terrifying puppies: affective primacy can attenuate the N400 effect in emotional discourse contexts

Words that are semantically congruous with their preceding discourse context are easier to process than words that are semantically incongruous with their context. This facilitation of semantic processing is reflected by an attenuation of the N400 event-related potential (ERP). We asked whether this was true of emotional words in emotional contexts where discourse congruity was conferred through emotional valence. ERPs were measured as 24 participants read two-sentence scenarios with critical words that varied by emotion (pleasant, unpleasant, or neutral) and congruity (congruous or incongruous). Semantic predictability, constraint, and plausibility were comparable across the neutral and emotional scenarios. As expected, the N400 was smaller to neutral words that were semantically congruous (vs. incongruous) with their neutral discourse context. No such N400 congruity effect was observed on emotional words following emotional discourse contexts. Rather, the amplitude of the N400 was small to all emotional words (pleasant and unpleasant), regardless of whether their emotional valence was congruous with the valence of their emotional discourse context. However, consistent with previous studies, the emotional words produced a larger late positivity than did the neutral words. These data suggest that comprehenders bypassed deep semantic processing of valence-incongruous emotional words within the N400 time window, moving rapidly on to evaluate the words' motivational significance.

Very early processing of emotional words revealed in temporoparietal junctions of both hemispheres by EEG and TMS

We investigate the contribution of both hemispheres in a lateralised lexical decision paradigm with emotional and neutral words in healthy volunteers. In a first experiment, high-density EEG analysis using source imaging methods revealed early specific participation of the temporoparietal junctions (TPJ) in both hemispheres for the detection of words. Then, in an event-related transcranial magnetic stimulation experiment with the same task, the disruption of left or right TPJ compared with a control stimulation over the vertex showed a slowing that is more pronounced when words are emotional and presented in the left visual field (LVF). This indicates that interference with both left and right TPJ results in impaired processing of words that were presented to the LVF. In addition, these results point to a specific cooperative contribution of the right hemisphere in the processing of words with emotional content compared with neutral words at very early stages. Results from the two experiments can be integrated in a brain-based spatiotemporal model of the early detection of written words.

Core disgust and moral disgust are related to distinct spatiotemporal patterns of neural processing: an event-related potential study

Core disgust is thought to rely more on sensory and perceptual processes, whereas moral disgust is thought to rely more on social evaluation processes. However, little is known about the neurocognitive mechanisms underlying these two types of disgust. We recorded event-related potentials (ERPs) from participants while they performed a lexical decision task in which core- and moral-disgust words were intermixed with neutral words and pseudowords. Lexical judgment was faster for coredisgust words and slower for moral-disgust words, relative to the neutral words. Core-disgust words, relative to neutral words, elicited a larger early posterior negative (EPN), a larger N320, a smaller N400, and a larger late positive component (LPC), whereas moral disgust words elicited a smaller N320 and a larger N400 than neutral words. These results suggest that the N320 and N400 components are particularly sensitive to the neurocognitive processes that overlap in processing both core and moral disgust, whereas the EPN and LPC may reflect process that are particularly sensitive to core disgust.

Caffeine improves left hemisphere processing of positive words

A positivity advantage is known in emotional word recognition in that positive words are consistently processed faster and with fewer errors compared to emotionally neutral words. A similar advantage is not evident for negative words. Results of divided visual field studies, where stimuli are presented in either the left or right visual field and are initially processed by the contra-lateral brain hemisphere, point to a specificity of the language-dominant left hemisphere. The present study examined this effect by showing that the intake of caffeine further enhanced the recognition performance of positive, but not negative or neutral stimuli compared to a placebo control group. Because this effect was only present in the right visual field/left hemisphere condition, and based on the close link between caffeine intake and dopaminergic transmission, this result points to a dopaminergic explanation of the positivity advantage in emotional word recognition.

Emotion, Etmnooi, or Emitoon?--Faster lexical access to emotional than to neutral words during reading

Cortical processing of emotional words differs from that of neutral words. Using EEG event-related potentials (ERPs), the present study examines the functional stage(s) of this differentiation. Positive, negative, and neutral nouns were randomly mixed with pseudowords and letter strings derived from words within each valence and presented for reading while participants' EEG was recorded. Results indicated emotion effects in the N1 (110-140 ms), early posterior negativity (EPN, 216-320) and late positive potential (LPP, 432-500 ms) time windows. Across valence, orthographic word-form effects occurred from about 180 ms after stimulus presentation. Crucially, in emotional words, lexicality effects (real words versus pseudowords) were identified from 216 ms, words being more negative over posterior cortex, coinciding with EPN effects, whereas neutral words differed from pseudowords only after 320 ms. Emotional content affects word processing at pre-lexical, lexical and post-lexical levels, but remarkably lexical access to emotional words is faster than access to neutral words.