ERP of Emotional Processing (Literature Research)

Some journals below can be found in this paper compilation https://www.researchrabbitapp.com/collection/public/360GQXW2ZG

Dissociable Effects of Valence and Arousal on Different Subtypes of Old/New Effect: Evidence from Event-Related

xu2015.pdf

The study investigated the effects of valence and arousal on different subtypes of old-new effect
ERPs (FN400 and LPC) were recorded during the memory retrieval task and focused on two subtypes of the old/new effect: the "recollection" effect and the "familiarity" effect.
Participants were presented with pictures of different valence (positive, negative, and neutral) and arousal (high and low) levels. They were then presented with a series of test pictures, some of which were old pictures from the study phase and some of which were new pictures. The participants were instructed to indicate whether each test picture was old or new and to rate their confidence in their response.
It was found that emotional valence and arousal had dissociable effects on the two old/new effect subtypes. Specifically, positive valence increased the familiarity effect, while negative valence increased the recollection effect. In addition, high arousal increased the recollection effect but had no effect on the familiarity effect.

Affective picture processing: An integrative review of ERP findings

oloffson2008.pdf

It's a long review of ERP studies in valence and arousal images to elicit emotional processing
Affective picture stimuli have been used to assess emotional reactions with ERP.
Early findings suggested that intensive emotional pictures elicit an increased P300 “irrespective of the pleasant or unpleasant nature of the emotion-induced.”
Stimuli used in these affective ERP studies: International Affective Picture System (IAPS). It's like OASIS, but these images are rated with respect to their valence category (unpleasant-to-pleasant) and arousal level (low-to-high) on a nine-point scale by both female and male young adults.

Conclusion:

The primary affective dimensions of valence and arousal influence ERP amplitudes at several processing stages that occur at separate and overlapping latencies.

Valence effects were mainly found at short latencies (100-300ms) indexed by P3b subcomponent, the rapid selective attention processes within the “negativity bias”.

ERP valence effects are less consistently obtained than arousal effects.

Arousal effects elicit a positive-going waveform from about 200 ms until stimulus offset, consistently obtained but varies with task relevance within the P300 range.

Motivational stimuli facilitate processing for subsequent memory storage at longer latencies

ERP arousal effects can be inhibited by emotional reappraisal and task instructions, especially at longer latencies.

The selective processing of briefly presented affective pictures: An ERP analysis

schupp2004.pdf

Previous findings:

Affective pictures draw attentional resources (Lang et al., 1997)
emotionally arousing (pleasant and unpleasant) pictures elicited enlarged late positive potentials (LPPs) compared to neutral images, which developed around 350–400 ms and lasted for several hundred milliseconds (Cuthbert et a;., 2000)
LPP reflect further processing related to the perceptual demands of the task after the initial stimulus identification is completed (e.g., Ritter & Ruchkin, 1992)
When we find something emotionally relevant, our brain pays more attention to it and continues to process it. This is called motivated attention because important things get our attention more easily, reflected by LPP.
Our brain reacts quickly to pictures, and emotional pictures create stronger reactions. This is reflected in patterns of brain activity called early posterior negativity (EPN), which appears 150 ms after seeing the picture and is stronger for more arousing pictures around 300 ms (over temporo-occipital). This shows that our brain selectively processes emotional pictures.
By looking at emotional pictures for a short time can activate our positive or negative motivation, particularly ‘‘affective pictures draw more heavily on attentional resources at encoding than do neutral pictures’’

Research Question / Hypothesis:

Can selective processing of emotional pictures be observed when pictures are presented briefly, and do early, and late selective modulations (the ERPs: EPN and LPP) vary with the emotional intensity of the pictures ( particularly for erotica and mutilations)?

Methods (research design, participants, procedures

Participants: 16 participants (14 women), between 19 and 27 years old, with a mean age of 21.2 years.
Participants viewed 60 pictures from the International Affective Picture System (IAPS) randomly presented in sequences of six exemplars.
The study measured ERPs with a dense sensor electrode array.
Pleasant picture contents included high-arousing images displaying heterosexual couples in erotic postures and low-arousing images of babies and family scenes.
Neutral images were either showing household objects or pictures of people posing neutral expressions.
Unpleasant images included images of mutilations and threats (animal and human threats).
Pictures were displayed for 120 ms and presented serially in sequences of six pictures.
Each picture was viewed four times in a total of 240 presentations.
An evaluation task was used to ensure that the participant was attending to the pictures.
The participant was asked to categorize each picture as pleasant, neutral, or unpleasant using a three-way response button.
Participants were asked to withhold the rating until a soft tone presented 1.5 s after picture onset signaled the beginning of the subjective rating period.

Current Findings:

Briefly presented affective pictures engage appetitive and aversive motivational systems, as indexed by specific changes in facial EMG activity, startle reflex modulation, and autonomic changes.
Selective processing of briefly presented pictures is similar to those found for longer presentations and consistent with the hypothesis that affective pictures draw attentional resources.
Selective processing of affective cues varied with the emotional intensity of the pictures.
The early selective processing of emotional cues is observed as a pronounced relative negative shift in the ERP waveform over temporo-occipital leads that started around 150 ms after picture onset and reached its peak around 300 ms.
Late selective processing effects were indicated by enlarged LPP amplitudes to emotional compared to neutral images over centro-parietal sensors.
The selective processing of affective cues is a default mechanism, which can be observed while subjects pursue other explicit cognitive goals.
The selective processing of emotional cues does not depend on the explicit categorization of the pictures but might depend on the availability of processing resources

Affective ERP Processing in a Visual Oddball Task: Arousal, Valence, and Gender.

nihms77171.pdf

Previous findings:

ERPs are used to assess both dimensions, with valence effects typically observed for early components (100-250 ms) and arousal effects for later components (250-850 ms)
Affective ERP modulations can be obtained from passive viewing, active discrimination tasks, and oddball paradigms
Negative affective valence produces stronger ERP modulation than positive affective valence pictures
Affective processing can occur automatically without conscious awareness if emotional stimuli are passively encountered
Affective ERP effects can also be obtained when a performance task is used to elicit a behavioral response to affective stimuli, although the relative strength and stability of valence and arousal effects are unclear
Valence category influences early selective attention capture, especially for negative valence items that generate a negativity-bias
Stimulus arousal level governs emotional picture processing by modulating attentional resource allocation, such that P3 amplitude is larger for high arousal affective pictures
Affective picture stimuli elicit selective attention and influence the motivational system via arousal and resource allocation mechanisms
Females react more to unpleasant valence pictures, whereas males react more to arousing pleasant pictures, implying that genders may differentially process affective stimuli

Research Question / Hypothesis / Objective: The study aimed to investigate how valence and arousal levels of images affect brain responses, using an oddball paradigm with both male and female participants. The hypothesis was that valence would affect early ERP components, arousal would affect later ERP components, and gender would influence the magnitude of these effects.

Methods:

Participants: 32 right-handed (16F, 16M)
Stimuli: IAPS images with varying valence and arousal levels; negative valence and high arousal images were selected as target stimuli for an oddball task with a 0.40 probability; a standard image with a 0.60 probability was used
Procedure: Participants sat 75 cm from the computer screen and responded with a mouse-click when a target picture stimulus was presented and refrained from responding when the standard stimulus was presented; task conditions were presented twice with a random order to yield 32 target presentation trials for each stimulus category; error rate and response time were recorded
Recording conditions: EEG activity was recorded from 21 electrode sites including Fz, Cz, Pz, Fp1/2, F3/4, F7/8, C3/4, T7/8, P3/4, P7/8, O1/2, balanced reference electrodes, and EOG

Main findings / conclusion:

High-arousal stimuli produce larger ERP amplitudes compared to low-arousal stimuli, starting from the N2 component and becoming stronger for the P3 and early and late slow wave components.
Gender differences were not robust or consistent across the components, with the strongest gender-related finding found for N1 amplitude within two interactions.
Affective ERP amplitude effects were elicited automatically, and the target task processing attenuated early ERP valence effects but facilitated resource allocation to produce arousal effects for the later ERPs.
Arousal effects begin just before the P3 potential occurs and continue through the early and late slow wave components, while valence effects are detectable in both the early and later components.
The increased ERP amplitudes for high-arousal stimuli could reflect the task-driven engagement of attention and subsequent memory operations, consistent with similar increased P3 and slow wave amplitudes for correctly remembered non-affect items.
Physical picture attributes such as color, complexity, and featural composition contribute to affective ERP processing, with early perceptual effects reflecting emotional content and later ERP modulations indexing fundamental motivational relevance.

The effect of arousal on regulation of negative emotions using cognitive reappraisal: An ERP study

langeslag2017.pdf

Background / Previous Findings:

Emotion regulation is the use of strategies to control emotions.
Distraction and cognitive reappraisal are multiple regulation strategies.
Reappraisal is a common strategy studied in down-regulating negative emotions. Some studies have focused on up-regulating negative and positive emotions.
Emotion regulation instructions modulate the late positive potential (LPP) according to the regulatory goal and can be used as an index of regulation success.
Some previous studies did not observe the typical LPP reduction by down-regulation, possibly due to floor or ceiling effects.
Floor effect refers to down-regulating weak emotions, and the ceiling effect refers to up-regulating intense emotions.
Reappraisal may not be effective for down-regulating intense emotions when high background arousal is present.

Research Question / Hypothesis / Objective: The purpose of this study was to investigate how stimulus arousal affects the success of cognitive reappraisal, a popular emotion regulation strategy, by analyzing self-reported valence and Late Positive Potential (LPP) amplitude.

Methods:

31 participants (Mean age = 24.8 years, range = 19-39 years, and 19 women)
Stimuli: 30 neutral, 90 low arousings, and 90 high arousing unpleasant pictures from the International Affective Picture System (IAPS).
Each picture is presented only once to avoid confounding by ERP old/new effects.
The 90 low and 90 high arousing unpleasant pictures were divided into three sets of 30 pictures each, assigned to one of the regulation conditions.
Participants completed three practice trials in which they passively viewed neutral pictures.
Seven task blocks: 1 - Participants passively viewed neutral pictures. 2 - Participants passively viewed low arousing unpleasant pictures. 3 - Participants passively viewed high arousing unpleasant pictures. 4- Participants up-regulated their responses to low arousing unpleasant pictures. 5 - Participants down-regulated their responses to low arousing unpleasant pictures. 6 - Participants up-regulated their responses to high arousing unpleasant pictures. 7 - Participants down-regulated their responses to high arousing unpleasant pictures.
Block order counterbalanced between participants.
Participants were instructed to increase or decrease the intensity of the emotion they felt in response to the picture by reinterpreting the situation.

Main findings/conclusion:

Passive viewing of unpleasant pictures (low and high arousing) elicited more negative and arousing feelings than neutral pictures
ERP more positive for low and high arousing unpleasant pictures than neutral pictures at parietal electrodes (400-1000 ms)
LPP larger for high-arousing unpleasant pictures than low-arousing unpleasant pictures
Using LPP amplitude during passive viewing as arousal variable could be useful for testing effect of arousal on reappraisal success
Up-regulation caused more negative feelings, while down-regulation caused less negative feelings
Emotion regulation did not change subjective arousal
LPP between 400-1000 ms not significantly affected by up/down-regulation of responses to low arousing pictures, but enhanced by down-regulation of responses to high arousing pictures
Enhanced LPP with down-regulation may reflect strategy selection or task design
LPP enhanced by up-regulation of responses to high arousing pictures (400-1000 ms), with small to medium effect almost reaching significance threshold
LPP regulation effects occurred at central electrodes, in line with centro-parietal topography of LPP
Direction of LPP amplitude effects on emotion regulation cannot be attributed to floor and ceiling effects
Self-focused reappraisal more popular than situation-focused reappraisal to up-regulate negative emotions, but both equally popular to down-regulate negative emotions
Some participants reported thinking unrelated thoughts, a popular strategy to down-regulate negative emotions
Limitation: Arousal and LPP differences between low and high arousing unpleasant pictures during passive viewing did not reach significance
Limitation: Stimulus duration of one second was relatively short; future studies may explore effects of arousal on regulation effects on LPP amplitude after stimulus offset

Event-Related Potentials, Emotion, and Emotion Regulation: An Integrative Review

87565640903526504.pdf

Review Highlights:

Emotional stimuli elicit a sustained increase in attention and processing resources, which can be indexed by modulation of positivities in the stimulus-locked ERP, including the P300 and the late positive potential (LPP).
The LPP might reflect the neuromodulatory activity of the locus coeruleus norepinephrine system.
Top-down strategies involving cognitive control can also affect measures of emotional processing.
The LPP is sensitive to various emotion regulation instructions, including meaning change, task relevance, spatial attention, and cognitive load.
The duration of the LPP can be prolonged following instructions to imagine recently viewed pictures, which might be an important metric for indexing emotion regulation.
The P300 component of the ERP, which is a broad positivity observed between 300-500 msec following stimulus presentation.
The P300 reflects the allocation of limited cognitive resources towards motivationally salient stimuli.
Emotional stimuli capture attention automatically and elicit larger ERP components within 200-300 msec following stimulus onset. This early processing of emotional information is termed "motivated attention" and might make emotional stimuli natural targets.
Several studies have reported increased P300 amplitudes following the presentation of emotional compared to neutral stimuli.
The increased LPP for emotional stimuli does not habituate over repeated presentations of stimuli, unlike other measures such as skin conductance, heart rate, facial EMG, and amygdala activation.
The LPP requires conscious recognition and is related to the emotional intensity of stimuli, driven by motivational salience, and not simply stimulus novelty or low-level perceptual differences.
Emotional modulation of the LPP can extend for seconds and is linked to memory encoding and storage.
Differentiating experimental effects on the P300 versus the LPP can be problematic, especially in the 300 to 1,000 msec time range, and the longer duration of the LPP suggests some distinction from the classic P300.
Emotional modulation of the P300 is evident predominantly at occipital-parietal sites around 350 msec following picture onset, whereas emotional modulation of the LPP appears evident at occipital to central recording sites with peaks about 850 and 1,600 msec following picture presentation.
Evaluating the P300/LPP in multiple windows following stimulus presentation, and examining more frontal/central activity later in the recording epoch, is suggested.

CIMH-Clinical-Psychology / EMO_REACT