Affective motivational direction drives asymmetric frontal hemisphere activation

Sleep apnea evokes right hemisphere dominance and psychological disorders: An exploratory study

BACKGROUND

Obstructive sleep apnea (OSA) is considered one of the major causes of sleep disorders and psychological disorders in individuals. Brain asymmetry (BA) demonstrates individual hemispheric activity and psychological disorders. This study aimed to explore the characteristics of BA and psychology in OSA.

METHODS

Enrolment of patients for sleep assessment at the Sleep Medicine Center. Clinical characteristics, handedness, and psychological scales were prospectively collected from subjects. Subsequently, EEG power in alpha, beta, and theta bilaterally was calculated for the rest and sleep phases.

RESULTS

A total of 152 OSA and 21 non-OSA subjects were included in the study. In the frontal, central and occipital regions, OSA exhibited increased interhemispheric asymmetry with increasing apnea-hypopnea index (AHI) during rest and sleep. Simultaneously, the results showed that greater activity in the right hemisphere was positively associated with anxiety and extraversion, while inversely with positive and lie scale. In addition, the results show that OSA contributes to abnormal BA fluctuations during sleep.

CONCLUSIONS

Our results suggest that sleep disorders associated with apnea-hypopnea and arousal may contribute to increased BA during sleep. Such changes may persist into wakefulness with psychological traits.

Fear is more right lateralized than happiness and anger: Evidence for the motivational hypothesis of emotional face perception?

Facial emotion processing (FEP) tends to be right hemisphere lateralized. This right-hemispheric bias (RHB) for FEP varies within and between individuals. The aim of the present research was to examine evidence pertaining to the prominent theories of FEP hemispheric bias as measured by a half-emotional half-neutral (no emotion) chimeric faces task. FEP hemispheric bias was indexed using laterality quotients (LQs) calculated from a Chimeric Faces Task completed by 427 adults recruited from the general population aged 18-67 years. Participants indicated which of two identical (but mirrored) emotional-neutral chimeric faces were more emotive. While all investigated emotions (fear, anger, and happiness) were right lateralized, fear was significantly more right lateralized than anger and happiness. These results provide evidence for both the right hemisphere hypothesis and the motivational hypothesis of emotion perception.

Related neural networks underlie suppression of emotion, memory, motor processes as identified by data-driven analysis

BACKGROUND

Goal-directed behavior benefits from self-regulation of cognitive and affective processes, such as emotional reactivity, memory retrieval, and prepotent motor response. Dysfunction in self-regulation is a common characteristic of many psychiatric disorders, such as PTSD and ADHD. This study sought to determine whether common intrinsic connectivity networks (ICNs; e.g. default mode network) are involved in the regulation of emotion, motor, and memory processes, and if a data-driven approach using independent component analysis (ICA) would successfully identify such ICNs that contribute to inhibitory regulation.

METHODS

Eighteen participants underwent neuroimaging while completing an emotion regulation (ER) task, a memory suppression (Think/No-Think; TNT) task, and a motor inhibition (Stop Signal; SS) task. ICA (CONN; MATLAB) was conducted on the neuroimaging data from each task and corresponding components were selected across tasks based on interrelated patterns of activation. Subsequently, ICNs were correlated with behavioral performance variables from each task.

RESULTS

ICA indicated a common medial prefrontal network, striatal network, and frontoparietal executive control network, as well as downregulation in task-specific ROIs.

CONCLUSIONS

These results illustrate that common ICNs were exhibited across three distinct inhibitory regulation tasks, as successfully identified through a data-driven approach (ICA).

Motivation in the metaverse: A dual-process approach to consumer choices in a virtual reality supermarket

Introduction

Consumer decision-making processes involve a complex interrelation between perception, emotion, and cognition. Despite a vast and diverse literature, little effort has been invested in investigating the neural mechanism behind such processes.

Methods

In the present work, our interest was to investigate whether asymmetrical activation of the frontal lobe of the brain could help to characterize consumer's choices. To obtain stronger experimental control, we devised an experiment in a virtual reality retail store, while simultaneously recording participant brain responses using electroencephalogram (EEG). During the virtual store test, participants completed two tasks; first, to choose items from a predefined shopping list, a phase we termed as "planned purchase". Second, subjects were instructed that they could also choose products that were not on the list, which we labeled as "unplanned purchase." We assumed that the planned purchases were associated with a stronger cognitive engagement, and the second task was more reliant on immediate emotional responses.

Results

By analyzing the EEG data based on frontal asymmetry measures, we find that frontal asymmetry in the gamma band reflected the distinction between planned and unplanned decisions, where unplanned purchases were accompanied by stronger asymmetry deflections (relative frontal left activity was higher). In addition, frontal asymmetry in the alpha, beta, and gamma ranges illustrate clear differences between choices and no-choices periods during the shopping tasks.

Discussion

These results are discussed in light of the distinction between planned and unplanned purchase in consumer situations, how this is reflected in the relative cognitive and emotional brain responses, and more generally how this can influence research in the emerging area of virtual and augmented shopping.

Exercise Task Characteristics Influence Time Perception During Vigorous Exercise

The passage of time is observed subjectively, and changes rate based on attentional or physiological stimuli. Self-adjusted exercise typically leads to the experience that time is progressing more slowly than it really is, but only when intensity is sufficiently high. This study was designed to determine if high exercise intensity at a fixed work rate would lead to differences in subjective timing. Subjects (26 total; 17 men/ 9 women) completed a maximal exercise test on a Velotron cycle ergometer until volitional exhaustion. A time production task was completed at baseline prior to exercise, and during each 3-min stage. Heart rate (HR) was assessed continuously. Time perception ratio (actual time divided by perceived time) was compared at baseline, during light exercise (40 W), and during the first stage at which age-predicted HRmax was considered vigorous (76–90% HRmax), using a repeated-measures analysis of variance (ANOVA). The result of the ANOVA was significant, F1.63,39 = 6.19, p = 0.007, η2 = 0.21. Bonferroni-adjusted post-hoc comparisons showed that the time perception ratio was higher during vigorous exercise (1.21 ± 0.34) compared to baseline (1.06 ± 0.19; p = 0.028) and light (1.09 ± 0.27; p = 0.048) exercise. Unlike several similar studies finding that subjective time increases at higher exercise intensities, the results of this study indicate the opposite effect at a fixed vigorous-intensity work rate. The motivational nature of the task and unique attentional factors associated with it are likely explanations for the deviation from earlier reports.

A Review on the Role of Affective Stimuli in Event-Related Frontal Alpha Asymmetry

Frontal alpha asymmetry refers to the difference between the right and left alpha activity over the frontal brain region. Increased activity in the left hemisphere has been linked to approach motivation and increased activity in the right hemisphere has been linked to avoidance or withdrawal. However, research on alpha asymmetry is diverse and has shown mixed results, which may partly be explained by the potency of the used stimuli to emotionally and motivationally engage participants. This review gives an overview of the types of affective stimuli utilized with the aim to identify which stimuli elicit a strong approach-avoidance effect in an affective context. We hope this contributes to better understanding of what is reflected by alpha asymmetry, and in what circumstances it may be an informative marker of emotional state. We systematically searched the literature for studies exploring event-related frontal alpha asymmetry in affective contexts. The search resulted in 61 papers, which were categorized in five stimulus categories that were expected to differ in their potency to engage participants: images & sounds, videos, real cues, games and other tasks. Studies were viewed with respect to the potency of the stimuli to evoke significant approach-avoidance effects on their own and in interaction with participant characteristics or condition. As expected, passively perceived stimuli that are multimodal or realistic, seem more potent to elicit alpha asymmetry than unimodal stimuli. Games, and other stimuli with a strong task-based component were expected to be relatively engaging but approach-avoidance effects did not seem to be much clearer than the studies using perception of videos and real cues. While multiple factors besides stimulus characteristics determine alpha asymmetry, and we did not identify a type of affective stimulus that induces alpha asymmetry highly consistently, our results indicate that strongly engaging, salient and/or personally relevant stimuli are important to induce an approach-avoidance effect.

Minimum spanning tree based graph neural network for emotion classification using EEG

Emotion classification based on neurophysiology signals has been a challenging issue in the literature. Recent neuroscience findings suggest that brain network structure underlying the different emotions provides a window in understanding human affection. In this paper, we propose a novel method to capture the distinct minimum spanning tree (MST) topology underpinning the different emotions. Specifically, we propose a hierarchical aggregation-based graph neural network to investigate the MST structure in emotion recognition. Extensive experiments on the public available DEAP dataset demonstrate the superior performance of the model in emotion classification as compared to existing methods. In addition, the results show that the theta, lower beta and gamma frequency band network information are more sensitive to emotions, suggesting a multi-frequency interaction in emotion processing.

Spectral Characteristics of EEG during Active Emotional Musical Performance

The research on neural correlates of intentional emotion communication by the music performer is still limited. In this study, we attempted to evaluate EEG patterns recorded from musicians who were instructed to perform a simple piano score while manipulating their manner of play to express specific contrasting emotions and self-rate the emotion they reflected on the scales of arousal and valence. In the emotional playing task, participants were instructed to improvise variations in a manner by which the targeted emotion is communicated. In contrast, in the neutral playing task, participants were asked to play the same piece precisely as written to obtain data for control over general patterns of motor and sensory activation during playing. The spectral analysis of the signal was applied as an initial step to be able to connect findings to the wider field of music-emotion research. The experimental contrast of emotional playing vs. neutral playing was employed to probe brain activity patterns differentially involved in distinct emotional states. The tasks of emotional and neutral playing differed considerably with respect to the state of intended-to-transfer emotion arousal and valence levels. The EEG activity differences were observed between distressed/excited and neutral/depressed/relaxed playing.

Differential Hemispheric Lateralization of Emotions and Related Display Behaviors: Emotion-Type Hypothesis

There are two well-known hypotheses regarding hemispheric lateralization of emotions. The Right Hemisphere Hypothesis (RHH) postulates that emotions and associated display behaviors are a dominant and lateralized function of the right hemisphere. The Valence Hypothesis (VH) posits that negative emotions and related display behaviors are modulated by the right hemisphere and positive emotions and related display behaviors are modulated by the left hemisphere. Although both the RHH and VH are supported by extensive research data, they are mutually exclusive, suggesting that there may be a missing factor in play that may provide a more accurate description of how emotions are lateralization in the brain. Evidence will be presented that provides a much broader perspective of emotions by embracing the concept that emotions can be classified into primary and social types and that hemispheric lateralization is better explained by the Emotion-type Hypothesis (ETH). The ETH posits that primary emotions and related display behaviors are modulated by the right hemisphere and social emotions and related display behaviors are modulated by the left hemisphere.

Romantic love affects emotional processing of love-unrelated stimuli: An EEG/ERP study using a love induction task

The aim of the present study was to investigate (a) the neural correlates of a love induction task (LIT) including listening to love-related songs and thinking about the romantic relationship, and (b) the effects of romantic love on the emotional processing of love-unrelated stimuli during a passive viewing task. The EEG was recorded in two groups of university students: people in love (Love Group, LG, N = 22, 19 F) and people not in love (Control Group, CG, N = 20, 15 F). The LIT induced higher pleasantness and arousal in the LG than in the CG, as well as higher alpha activity in occipital-right electrodes, suggesting active mental imagery and internal focused attention. During the picture viewing task, the LG displayed larger N1 amplitudes than the CG in response to unpleasant pictures, and lower amplitudes of the late positive potential to both pleasant and unpleasant pictures at frontal sites. Overall, these results suggest an early attentional modulation of the neural responses to unpleasant, mood-incongruent cues, followed by an implicit emotional down-regulation of arousing stimuli, which might have important implications for everyday attitudes and behaviors.

Affectionate Touch in the Context of Breastfeeding and Maternal Depression Influences Infant Neurodevelopmental and Temperamental Substrates

BACKGROUND

While numerous studies have demonstrated maternal depression's influence on infant brain development, few studies have examined the changes that occur as a consequence of co-occurring experiential factors that affect quality of mother and infant affectionate touch as well as infant temperament and neurophysiological systems. The aim of the study was to examine the interactive effects of maternal depression and breastfeeding on mother and infant affectionate touch and infant temperament and cortical maturation patterns across early development.

METHODS

113 mothers and their infants participated when infants were 1 and 3 months of age. Questionnaires to assess maternal depressive symptoms, feeding, and temperament were completed. Tonic EEG patterns (asymmetry and left and right activity) were collected and the dyads were video-recorded during feeding to assess mother and infant affectionate touch patterns.

RESULTS

Data analysis showed that EEG activity and mother-infant affectionate touch differed as a function of mood and feeding method. Notably, only infants of depressed mothers that bottle-fed showed right frontal EEG asymmetry and attenuated change in the left frontal region across 3 months. Breastfeeding positively impacted affectionate touch behaviors and was associated with increased left and decreased right frontal EEG activation even for depressed groups. Furthermore, a model incorporating physiology, maternal depression, touch, temperament, and feeding indicated significant prediction for infant affectionate touch (with breastfeeding and affectively positive temperament demonstrating the strongest prediction). Con-clusion: The findings suggest that breastfeeding and the infant's positive temperament influence mother-infant affectionate touch patterns and result in neuroprotective outcomes for infants, even those exposed to maternal depression within early development.

Frontal Asymmetry in an approach-avoidance conflict paradigm

The frontal cortex appears to be asymmetrically related to approach motivation, avoidance motivation, and motivational conflict. Much past work has investigated approach and avoidance motivation, but little work has investigated frontal asymmetry in the face of motivational conflict in part because of the inherent conflict between avoidance motivation and motivational conflict. The current study sought to disentangle the existing confound between avoidance motivation and motivational conflict. In the study, participants selected the likelihood of viewing negative (vs. positive) images for zero reward points (avoidance only condition), or negative (vs. positive) images for the chance to win reward points (approach-avoidance conflict conditions). Participants exhibited greater relative right frontal asymmetry while making percent likelihood selections in the approach-avoidance conflict conditions relative to the avoidance only conditions. Additionally, participants exhibited greater relative right frontal asymmetry while viewing disgust images during trials with the greatest approach-avoidance conflict relative to trials with the lowest approach-avoidance conflict. Together, these results suggest that motivational conflict, and not avoidance motivation, is associated with greater relative right frontal activity.

Revenge is sweet: Investigation of the effects of Approach-Motivated anger on the RewP in the motivated anger delay (MAD) paradigm

Past research has found that neural activity associated with feedback processing is enhanced by positive approach-motivated states. However, no past work has examined how reward processing changes in the context of revenge. Using a novel aggression paradigm, we sought to explore the influence of approach-motivated anger on neural responses to feedback indicating the opportunity to seek revenge against an offending opponent by examining the reward positivity (RewP), an event-related potential indexing performance feedback. In Experiment 1, after receiving insulting feedback from an opponent, participants played a reaction time game with three trial types: revenge trials, aggravation trials, and no-consequence trials. Results revealed that RewP amplitudes were larger to revenge trial win feedback than no-consequence trial win feedback or revenge trial loss feedback. RewP amplitudes were larger to both aggravation trial win and loss feedback than on no-consequence trials. Experiment 2 examined the influence of approach-motivated anger during the acquisition of rewards on the RewP without the possibility of retribution from the offending individual. Participants played a reaction time game similar to Experiment 1, except instead of giving or receiving noise blasts, participants could win money from the insulter (revenge trials) or a neutral-party (e.g., bank). Results indicated that revenge wins elicited larger RewP amplitudes than bank wins. These results suggest that anger enhances revenge-related RewP amplitudes to obtaining revenge opportunities and further aggravation wins or losses. Anger appears to enhance the pleasurable feelings of revenge.

A conceptual critique of brain lateralization models in emotional face perception: Toward a hemispheric functional-equivalence (HFE) model

The present review proposes a novel dynamic model of brain lateralization of emotional (happy, surprised, fearful, sad, angry, and disgusted) and neutral face perception. Evidence to date suggests that emotional face perception is lateralized in the brain. At least five prominent hypotheses of the lateralization of emotional face perception have been previously proposed; the right-hemisphere hypothesis; the valence-specific hypothesis; the modified valence-specific hypothesis; the motivational hypothesis; and behavioral activation/inhibition system hypothesis. However, a growing number of recent replication studies exploring those hypotheses frequently provide inconsistent or even contradictory results. The latest neuroimaging and behavioral studies strongly demonstrate the functional capacity of both hemispheres to process emotions relatively successfully. Moreover, the flexibility of emotional brain-networks in both hemispheres is functionally high even to the extent of a possible reversed asymmetry of the left and the right hemisphere performance under altered neurophysiological and psychological conditions. The present review aims to a) provide a critical conceptual analysis of prior and current hypotheses of brain lateralization of emotional and neutral face perception; b) propose an integrative introduction of a novel hemispheric functional-equivalence (HFE) model in emotional and neutral face perception based on the evaluation of theoretical considerations, behavioral and neuroimaging studies: the brain is initially right-biased in emotional and neutral face perception by default; however, altered psychophysiological conditions (e.g., acute stress, a demanding emotional task) activate a distributed brain-network of both hemispheres toward functional equivalence that results in relatively equalized behavioral performance in emotional and neutral face perception. The proposed novel model may provide a practical tool in further experimental investigation of brain lateralization of emotional face perception.

EEG Frontal Asymmetry and Theta Power in Unipolar and Bipolar Depression

BACKGROUND

Distinguishing between unipolar and bipolar depression is of high clinical relevance. However, there is sparse research directly comparing these groups in terms of EEG activity.

METHOD

We investigated 87 participants' left and right EEG frontal alpha-1, alpha-2, and theta activity related to happy and sad face stimuli in unipolar (UD, n=33) and bipolar (BD, n=22) depressed participants, and controls without depression (HC, n=32).

RESULTS

Post-hoc analysis of an observed hemisphere x group interaction (p< .037) showed significant differences in alpha-1 asymmetry only for the comparison of UD and HC (p< .006). Further analysis of a significant emotion x group interaction (p= .001) revealed a differential impact of stimulus valence on theta power between the groups (p< .001). The valence dependent theta power of the BD differed from that of the UD (p< .0002) and the HC (p< .004). Alpha-1 asymmetry classified HC and both depressed groups with an accuracy of .69. Valence-related theta classified BD from UD with an accuracy of .83. Leave-one-out cross validation resulted in slightly reduced accuracy.

LIMITATIONS

Important limitations were the small sample size and that subjects were not medication-free.

CONCLUSIONS

Our results demonstrate the value of simple, task related EEG activity for differentiating not only healthy individuals from those with depression, but also individuals with unipolar depression from those with bipolar depression.

Resting EEG Asymmetry Markers of Multiple Facets of the Behavioral Approach System: A LORETA Analysis

Previously published models of frontal activity linked high relative left frontal activity to the behavioral approach system (BAS) and impulsivity. Additionally, these models did not account for BAS facets encompassing the anticipation of reward, i.e., goal-driven persistence (BAS–GDP) and reward interest (BAS–RI), from those that deal with the actual hedonic experience of reward, i.e., reward reactivity (BAS–RR) and impulsivity (BAS–I). Using resting electroencephalographic (EEG) recordings, the source localization (LORETA) method allowed us to calculate the hemispheric asymmetry of the current density within the alpha band (7.5–13 Hz) in ten regions of interest. Compared to low BAS subtrait scorers, high BAS subtrait scorers (except for BAS–I) were correlated with greater relative left-sided activity in the superior frontal gyrus (BA10). Further, an isolated effective coherence (iCOH) analysis of the beta activity (21 Hz) disclosed that high impulsive scorers as compared to low impulsive ones had higher connectivity between the superior frontal gyrus and middle temporal gyrus, which was not compensated for by enhanced inhibitory alpha (11 Hz) connectivity between these regions. For the beta frequency, we also found in highly impulsive individuals that (i) both left and right middle temporal lobes directly influenced the activity of the left and right superior frontal lobes, and (ii) a clear decoupling between left and right superior frontal lobes. These findings could indicate reduced control by the supervisory system in more impulsive individuals.

Resting-state functional connectivity of neural circuits associated with primary and secondary rewards in patients with bipolar disorder

Objective

We used resting-state functional connectivity (rsFC) to evaluate the integrity of the neural circuits associated with primary and secondary rewards in bipolar disorder (BD) with different mood phases.

Methods

Sixty patients with BD [21 patients with depressive episode of BD (BDD) and 41 patients with maniac episode of BD (BDM)] and 42 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging. rsFC was assessed using region of interest-wise analyses.

Results

Attenuation of rsFC at the orbitofrontal cortex (OFC) and the left ventral striatum (LVS) was observed in the secondary reward circuit of patients with BD compared to that of HCs. Among BDD, BDM and HCs, the rsFC between OFC and LVS in BDM was intermediate, while the rsFC between OFC and right ventral striatum/right amygdala in BDM was the highest; the corresponding rsFC values in BDD were the lowest. Furthermore, a positive correlation was found between rsFC and Young Mania Rating Scale scores in BDM.

Conclusions

This study suggests that there may be an abnormal rsFC between OFC and LVS in the second reward of patients with BD and the discrepant patterns of rsFC may exist between different mood states in patients with BD.

Functional brain asymmetry for emotions: psychological stress-induced reversed hemispheric asymmetry in emotional face perception

Empirical evidence has demonstrated functional (mostly right-biased) brain asymmetry for emotion perception, whereas recent studies indicate that acute stress may modulate left and/or right hemisphere activation. However, it is still unknown whether emotion perception can be influenced by stress-induced hemispheric activation since behavioral studies report inconsistent or even contradictory results. We sought to reevaluate this gap. Eighty-eight healthy Caucasian university students participated in the study. In half of the randomly selected participants, acute psychological stress was induced by displaying a brief stressful movie clip (the stress condition), whereas the other half were shown a neutral movie clip (the non-stress condition). Prior to (the baseline) and following the movie clip display an emotion perception task was applied by presenting an emotional (happy, surprised, fearful, sad, angry, or disgusted) or neutral face to the left or right visual field. We found a more accurate perception of emotional and neutral faces presented to the LVF (the right hemisphere) in the baseline. However, we revealed that after watching a neutral movie clip, behavioral performance in emotional and neutral face perception accuracy became relatively equalized for both visual fields, whereas after watching a stressful movie clip, the RVF (the left hemisphere) even became dominant in emotional face perception. We propose a novel hemispheric functional-equivalence model: the brain is initially right-biased in emotional and neutral face perception by default; however, psychophysiological activation of a distributed brain-network due to watching neutral movie clips redistributes hemispheric performance toward relative equivalence. Moreover, even reversed hemispheric asymmetry may occur.

An electrophysiological investigation on the emotion regulatory mechanisms of brief open monitoring meditation in novice non-meditators

Despite a growing literature supporting the salutary effects of mindfulness meditation on emotion regulation, the underlying mechanisms linking neural and subjective changes occurring during the actual practice of meditation with emotion regulatory effects observed after meditation remains virtually unexplored. The current study sought to address this gap in knowledge by testing the hypothesis that adoption of internally-directed focused attention, indexed by increased alpha and theta spectral power, during brief open monitoring (OM) mindfulness meditation predicts reduced emotional reactivity, as measured by the late positive potential (LPP). Results revealed that the OM meditation did not produce demonstrable differences in alpha and theta power but did increase self-reported sleepiness relative to controls. Follow-up analyses showed that sleepiness uniquely moderated the effect of meditation on the LPP, such that less sleepiness during meditation, but not the control audio, corresponded to smaller LPPs to negative images. Change in theta, but not alpha power, between meditation and rest was positively correlated with the LPP even after controlling for sleepiness. Although the primary hypothesis was unsupported, the findings demonstrate that phenomenological and neural changes occurring during OM meditation may modulate its subsequent “off-the-cushion” effects on emotional reactivity.

Hemispheric Asymmetry of Functional Brain Networks under Different Emotions Using EEG Data

Despite many studies reporting hemispheric asymmetry in the representation and processing of emotions, the essence of the asymmetry remains controversial. Brain network analysis based on electroencephalography (EEG) is a useful biological method to study brain function. Here, EEG data were recorded while participants watched different emotional videos. According to the videos’ emotional categories, the data were divided into four categories: high arousal high valence (HAHV), low arousal high valence (LAHV), low arousal low valence (LALV) and high arousal low valence (HALV). The phase lag index as a connectivity index was calculated in theta (4–7 Hz), alpha (8–13 Hz), beta (14–30 Hz) and gamma (31–45 Hz) bands. Hemispheric networks were constructed for each trial, and graph theory was applied to quantify the hemispheric networks’ topological properties. Statistical analyses showed significant topological differences in the gamma band. The left hemispheric network showed significantly higher clustering coefficient (C_p), global efficiency (E_g) and local efficiency (E_loc) and lower characteristic path length (L_p) under HAHV emotion. The right hemispheric network showed significantly higher C_p and E_loc and lower L_p under HALV emotion. The results showed that the left hemisphere was dominant for HAHV emotion, while the right hemisphere was dominant for HALV emotion. The research revealed the relationship between emotion and hemispheric asymmetry from the perspective of brain networks.

Subjective ratings of fear are associated with frontal late positive potential asymmetry, but not with early brain activity over the occipital and centro-parietal cortices

The human frontal cortex is asymmetrically involved in motivational and affective processing. Several studies have shown that the left-frontal hemisphere is related to positive and approach-related affect, whereas the right-frontal hemisphere is related to negative and withdrawal-related affect. The present study aimed to investigate whether evolutionarily threatening stimuli modulate asymmetrical frontal activity. We examined hemispheric differences in frontal late positive potentials (f-LPP asymmetry) and frontal alpha power activation (frontal alpha asymmetry, FAA) in response to images depicting snakes, spiders, butterflies, and birds. Results showed that the late component of f-LPP asymmetry, but not FAA, was modulated by the category of stimuli. Specifically, threatening stimuli (snakes and spiders) evoked a relatively large late f-LPP over the right-frontal hemisphere than non-threatening stimuli (birds and butterflies). Moreover, this relatively great right-frontal activity was positively associated with the subjective ratings of fear. Importantly, the subjective ratings of fear were not associated with early brain activity over the occipital or centro-parietal cortices. These results suggest that late f-LPP asymmetry may reflect higher order affective processes, specifically the subjective appraisal of threatening stimuli and the subjective experience of fear, that are independent of the fast and automatic processing of evolutionarily significant and affectively arousing stimuli.

Here's looking at you, kid? Maternal depression and adolescent attention to self- or other-directed emotional faces

BACKGROUND

Maternal depression history represents a significant risk factor for developing psychopathology in children, altered emotional responding may represent a central risk pathway. However, additional research is needed on factors that affect the strength or direction of response alterations in relation to depression-risk in youth. In particular, facial orientation and gaze direction may alter personal relevance, with emotions directed towards an individual heightening motivational salience, compared to emotions directed away.

METHODS

Mother-daughter dyads (N = 56) were recruited based on presence or absence of maternal depression history and absence of youth depression. In line with theoretical perspectives suggesting diminished sensitivity to emotional context in relation to depression risk, we examined three Event-Related Potential (ERP) components in relation to forward versus averted emotional faces in a sample of girls with and without a maternal history of depression: the N200, N400, and Late Positive Potential (LPP).

RESULTS

Results showed a significant maternal depression history by face-orientation effect. Low-risk girls exhibited more negative N200 and N400 amplitudes for straight (M = -3.72, SE = 0.83; M = -3.57, SE = 0.86) versus averted (M = -2.15, SE = 0.76; M = -1.68, SE = 0.81) faces, while girls of mothers with histories of depression showed undifferentiated N200 or N400 responses in relation to face orientation. For LPP amplitudes, low-risk girls exhibited significantly more positive LPP amplitudes than high-risk girls, but only for averted faces (M = 0.69, SE = 0.59 and M = -2.63, SE = 0.74, respectively).

LIMITATIONS

Cross-sectional design and limited sample.

CONCLUSIONS

Results indicate that familial depression risk is associated with altered responsivity to face-orientation, these were interpreted as representing differential sensitivity to the personal-relevance of emotional stimuli.

Altered lateral geniculate nucleus functional connectivity in migraine without aura: a resting-state functional MRI study

OBJECTIVES

To investigate the structural and functional connectivity changes of lateral geniculate nucleus (LGN) and their relationships with clinical characteristics in patients without aura.

METHODS

Conventional MRI, 3D structure images and resting state functional MRI were performed in 30 migraine patients without aura (MwoA) and 22 healthy controls (HC). The lateral geniculate nucleus volumes and the functional connectivity (FC) of bilateral lateral geniculate nucleus were computed and compared between groups.

RESULTS

The lateral geniculate nucleus volumes in patient groups did not differ from the controls. The brain regions with increased FC of the left LGN mainly located in the left cerebellum and right lingual gyrus in MwoA compared with HC. The increased FC of right LGN located in left inferior frontal gyrus in MwoA compared with HC. The correlation analysis showed a positive correlation between VLSQ-8 score and the increased FC of left cerebellum and right lingual gyrus.

CONCLUSIONS

Photophobia in MwoA could be mediated by abnormal resting state functional connectivity in visual processing regions, the pain perception regulatory network and emotion regulation network. This result is valuable to further understanding about the clinical manifestation and pathogenesis of migraine.

No Evidence of Improved Emotion Perception Through Unilateral Hand Contraction

Previous studies have identified improved cognitive performance from unilateral hand contraction to effect contralateral hemisphere activation. As little is known of whether this activation can improve emotion perception, this study examined any differences in perception accuracy and reaction times of matching photographs of human facial expressions presented to the left or right visual fields after left versus right hemisphere activation triggered by unilateral hand contractions. We used photographs of happy, sad, and neutral facial expressions presented briefly and simultaneously (two photographs in each presentation) either unilaterally (intrahemisphere condition) or bilaterally (interhemisphere condition). We recruited 68 university student participants (aged 19–23 years) and randomly assigned half of them to squeeze a dynamometer with the right hand, while the other half squeezed with the left hand, prior to performing the Dimond face-matching task. Matching of happy faces was faster than matching of sad faces. In females (but not males), perception accuracy was higher when stimuli were presented in the right (vs. left) visual field. We found no difference in emotion perception of photographs in either unilateral (intrahemispheric) or bilateral (interhemispheric) stimuli presentations as a function of hand contractions.

Motivational intensity and visual word search: Layout matters

Motivational intensity has been previously linked to information processing. In particular, it has been argued that affects which are high in motivational intensity tend to narrow cognitive scope. A similar effect has been attributed to negative affect, which has been linked to narrowing of cognitive scope. In this paper, we investigated how these phenomena manifest themselves during visual word search. We conducted three studies in which participants were instructed to perform word category identification. We manipulated motivational intensity by controlling reward expectations and affect via reward outcomes. Importantly, we altered visual search paradigms, assessing the effects of affective manipulations as modulated by information arrangement. We recorded multiple physiological signals (EEG, EDA, ECG and eye tracking) to assess whether motivational states can be predicted by physiology. Across the three studies, we found that high motivational intensity narrowed visual attentional scope by altering visual search strategies, especially when information was displayed sparsely. Instead, when information was vertically listed, approach-directed motivational intensity appeared to improve memory encoding. We also observed that physiology, in particular eye tracking, may be used to detect biases induced by motivational intensity, especially when information is sparsely organised.

Evidence for a general factor of behavioral activation system sensitivity

Individual differences in one's propensity to engage the behavioral activation system (BAS) and behavioral inhibition system (BIS) have primarily been studied with Caver and White's (1994) BIS/BAS scale. Whereas, Carver and White identified the BIS as a unidimensional scale, they identified three separable BAS group factors - drive, fun seeking, and reward responsiveness -which Carver urged against combining into a BAS total score. Despite this, a BAS total score has been used extensively although researchers have yet to test whether a BAS general factor exists and, if so, whether a BAS total score can be interpreted as primarily being a measure of the general factor. The current study observed that the best fitting BAS factor model of those we tested was a hierarchical model with three group facets and a general factor. This model was largely invariant across both sex and race/ethnicity. We show, for the first time, that a general factor accounts for the majority of the variance in BAS total scores. Due to the superior fit of the hierarchical model and variance accounted for by the general factor, we conclude that researchers are psychometrically justified in using a BAS total score.

Individual EEG measures of attention, memory, and motivation predict population level TV viewership and Twitter engagement

Television (TV) programming attracts ever-growing audiences and dominates the cultural zeitgeist. Viewership and social media engagement have become standard indices of programming success. However, accurately predicting individual episode success or future show performance using traditional metrics remains a challenge. Here we examine whether TV viewership and Twitter activity can be predicted using electroencephalography (EEG) measures, which are less affected by reporting biases and which are commonly associated with different cognitive processes. 331 participants watched an hour-long episode from one of nine prime-time shows (~36 participants per episode). Three frequency-based measures were extracted: fronto-central alpha/beta asymmetry (indexing approach motivation), fronto-central alpha/theta power (indexing attention), and fronto-central theta/gamma power (indexing memory processing). All three EEG measures and the composite EEG score significantly correlated across episode segments with the two behavioral measures of TV viewership and Twitter volume. EEG measures explained more variance than either of the behavioral metrics and mediated the relationship between the two. Attentional focus was integral for both audience retention and Twitter activity, while emotional motivation was specifically linked with social engagement and program segments with high TV viewership. These findings highlight the viability of using EEG measures to predict success of TV programming and identify cognitive processes that contribute to audience engagement with television shows.

Frontal EEG Asymmetry and Middle Line Power Difference in Discrete Emotions

A traditional model of emotion cannot explain the differences in brain activities between two discrete emotions that are similar in the valence-arousal coordinate space. The current study elicited two positive emotions (amusement and tenderness) and two negative emotions (anger and fear) that are similar in both valence and arousal dimensions to examine the differences in brain activities in these emotional states. Frontal electroencephalographic (EEG) asymmetry and midline power in three bands (theta, alpha and beta) were measured when participants watched affective film excerpts. Significant differences were detected between tenderness and amusement on FP1/FP2 theta asymmetry, F3/F4 theta and alpha asymmetry. Significant differences between anger and fear on FP1/FP2 theta asymmetry and F3/F4 alpha asymmetry were also observed. For midline power, midline theta power could distinguish two negative emotions, while midline alpha and beta power could effectively differentiate two positive emotions. Liking and dominance were also related to EEG features. Stepwise multiple linear regression results revealed that frontal alpha and theta asymmetry could predict the subjective feelings of two positive and two negative emotions in different patterns. The binary classification accuracy, which used EEG frontal asymmetry and midline power as features and support vector machine (SVM) as classifiers, was as high as 64.52% for tenderness and amusement and 78.79% for anger and fear. The classification accuracy was improved after adding these features to other features extracted across the scalp. These findings indicate that frontal EEG asymmetry and midline power might have the potential to recognize discrete emotions that are similar in the valence-arousal coordinate space.

Hemispheric asymmetries and emotions: Evidence from effective connectivity

The Right Hemisphere Hypothesis (RHH) posits that the right hemisphere is specialized in processing all emotions; the Valence Hypothesis (VH) suggests a left/right-hemispheric specialization for positive/negative emotions, respectively. Behavioural, neuroimaging and physiological investigations alternatively support either the RHH or the VH, but connectivity analyses have been hardly exploited in this field. In the present study, unilateral and bilateral presentations of positive (happy) and negative (angry) emotional faces were used during electroencephalographic (EEG) recordings, and estimation of effective connectivity was performed using the Directed Transfer Function, to estimate causal influences between brain regions (Granger causality approach). The results show a strong pattern of connectivity among different frontal areas (orbitofrontal and dorsolateral prefrontal cortex), attentional network (frontal eye field, intraparietal sulcus), visual occipital areas and temporal sites, mainly lateralized in the right hemisphere for all emotions, in accordance with the RHH. Moreover, a stronger pattern of connectivity is evident when stimuli are presented in accordance with the VH (positive/negative emotions to the left/right hemisphere, respectively). Finally, the results suggest a crucial role of the right dorsolateral prefrontal cortex in a top-down regulation toward different areas involved in emotional processing. We conclude that the RHH and the VH are not mutually exclusive, but they seem to coexist during affective perception.

Asymmetric hemisphere activation in tenderness: evidence from EEG signals

Emotions are processed asymmetrically by the human brain. Frontal alpha asymmetry (FAA) as measured by electroencephalographic (EEG) power in the alpha band (8–13 Hz), is a sensitive indicator of asymmetric brain activity in the frontal cortex. The current study aimed to analyze the frontal EEG asymmetries in terms of valence and motivational direction. We presented 37 participants with three film excerpts that were selected from the standard emotional film database to elicit three target emotions: tenderness, anger, and neutrality. Participants’ self-reports on their induced emotional responses and EEG signals were recorded and analyzed. The results showed that individuals displayed lower alpha power in the left hemisphere than the right hemisphere when they were watching a tender film, indicating that tenderness was positive and related to approach motivation. In contrast, when watching an angry movie, participants showed higher alpha power in the left hemisphere than the right hemisphere, suggesting that anger was negative and associated with withdrawal motivation. These findings help to link positive and approach-motivated tenderness with greater left hemispheric activation and state-anger with greater right hemispheric activation through the analysis of FAA.

Functional Hemispheric (A)symmetries in the Aged Brain-Relevance for Working Memory

Functional hemispheric asymmetries have been described in different cognitive processes, such as decision-making and motivation. Variations in the pattern of left/right activity have been associated with normal brain functioning, and with neuropsychiatric diseases. Such asymmetries in brain activity evolve throughout life and are thought to decrease with aging, but clear associations with cognitive function have never been established. Herein, we assessed functional laterality during a working memory task (N-Back) in a healthy aging cohort (over 50 years old) and associated these asymmetries with performance in the test. Activity of lobule VI of the cerebellar hemisphere and angular gyrus was found to be lateralized to the right hemisphere, while the precentral gyrus presented left > right activation during this task. Interestingly, 1-Back accuracy was positively correlated with left > right superior parietal lobule activation, which was mostly due to the influence of the left hemisphere. In conclusion, although regions were mostly symmetrically activated during the N-Back task, performance in working memory in aged individuals seems to benefit from lateralized involvement of the superior parietal lobule.

Depression symptom dimensions and asymmetrical frontal cortical activity while anticipating reward

Unipolar depression has been characterized as involving diminished approach motivation and reward sensitivity. A psychophysiological indicator of approach motivation involves an asymmetry in frontal EEG activity, such that greater left relative to right frontal cortical activity indicates increased approach motivation. Consistent with the perspective of reduced approach motivation tendencies, depression has been associated with decreased relative left frontal cortical activity. To date, supporting research has primarily relied on categorical diagnoses or composite symptom counts. However, given the heterogeneity in depression, it is unclear what specific symptom dimensions relate to decreased relative left frontal cortical activity. The present study examined the association between multiple depression symptom dimensions and asymmetrical frontal cortical activity while anticipating reward in separate undergraduate (n = 75) and clinical samples (current major depressive disorder [n = 68] and never depressed controls [n = 67]). All participants completed the Inventory of Depression and Anxiety Symptoms, a self-report measure of factor-analytically derived symptom dimensions. Frontal cortical activity was assessed during a computerized slot machine task while participants anticipated potential monetary reward or no incentive. In undergraduates with low depression symptoms and never depressed controls, reward trials relative to no-incentive trials elicited greater relative left frontal cortical activity. Furthermore, in both samples across all participants, increased dysphoria and lassitude symptoms were associated with decreased relative left frontal cortical activity while anticipating reward. The present study suggests that depression symptoms consistent with motivational disengagement are associated with decreased relative left frontal cortical activity.

The influence of frontal alpha-asymmetry on the processing of approach- and withdrawal-related stimuli-A multichannel psychophysiology study

The approach-withdrawal model of hemispheric activation suggests that left frontal cortical areas mediate approach, while right frontal cortical areas mediate withdrawal motivation. Within this framework, the present study investigates the association of frontal cortical asymmetry with attentional and emotional responses toward approach- and withdrawal-related emotional stimuli. Resting frontal asymmetry was measured from 43 students before they passively viewed negative, neutral, and positive emotional pictures. The startle reflex, skin conductance response, and subjective ratings of valence and arousal were assessed to quantify emotional responding, while attention was assessed with ERPs. We also assessed frontal asymmetry in response to the pictures. Results indicated that relatively stronger right frontal cortical activation was associated with increased N1 amplitudes and more negative subjective emotional evaluation of all stimuli. Furthermore, enhanced right frontal asymmetry (state and trait) was associated with diminished emotional modulation of the late positive potential. In contrast, no association of frontal asymmetry with defensive reflex physiology or activation of sympathetic nervous system activity was found. The current data suggest dissociable influence of resting frontal brain asymmetry on attentional and physiological processing of withdrawal- and approach-related stimuli. That is, asymmetrical frontal cortical brain activation might not modulate approach-/withdrawal-related motor responses and sympathetic arousal directly, but instead enhances allocation of attentional resources to subjectively significant stimuli. The results are discussed in terms of their potential importance for emotion perception in anxiety disorders and their contribution to the understanding of frontal asymmetry.

Understanding approach and avoidance in verbal descriptions of everyday actions: An ERP study

Understanding verbal descriptions of everyday actions could involve the neural representation of action direction (avoidance and approach) toward persons and things. We recorded the electrophysiological activity of participants while they were reading approach/avoidance action sentences that were directed toward a target: a thing/a person (i.e., "Petra accepted/rejected Ramón in her group"/ "Petra accepted/rejected the receipt of the bank"). We measured brain potentials time locked to the target word. In the case of things, we found a N400-like component with right frontal distribution modulated by approach/avoidance action. This component was more negative in avoidance than in approach sentences. In the case of persons, a later negative event-related potential (545-750 ms) with left frontal distribution was sensitive to verb direction, showing more negative amplitude for approach than avoidance actions. In addition, more negativity in approach-person sentences was associated with fear avoidance trait, whereas less negativity in avoidance-person sentences was associated with a greater approach trait. Our results support that verbal descriptions of approach/avoidance actions are encoded differently depending on whether the target is a thing or a person. Implications of these results for a social, emotional and motivational understanding of action language are discussed.

Spontaneous emotion regulation: differential effects on evoked brain potentials and facial muscle activity

Late positive potentials (LPPs) were found to be decreased during down-regulation and increased during up-regulation of positive and negative emotions. However, previous studies lack ecological validity, since they explicitly instructed their participants to use certain regulation strategies. The goal of our study was to test an ecologically more valid paradigm of emotion regulation. We therefore investigated the effects of freely chosen emotion regulation strategies on LPPs and additionally assessed facial EMG responses and valence and arousal ratings as control variables. Responses to positive IAPS pictures were marked by pleasant valence ratings and high activations of M. zygomaticus major, negative pictures elicited unpleasant valence ratings and high activations of M. corrugator supercilii, and both, positive and negative pictures, went along with increased arousal ratings and LPPs. Importantly, ratings and EMG activity were intensified through up-regulation and attenuated through down-regulation of emotions, while LPPs were increased through both up-and down-regulation. We conclude that LPPs in paradigms with free choice of emotion regulation strategies might be a marker of attentional resources required for the selection of adequate emotion up- and down-regulation strategies, while LPP effects following emotion regulation with specific, instructed strategies reflect modulated arousal processes.

Supervisory control system and frontal asymmetry: neurophysiological traits of emotion-based impulsivity

Approach, avoidance and the supervisory control system are fundamental to human behavior. Much past research has examined the neurophysiological models relating trait approach and avoidance. Using measures of electroencephalographic (EEG) frontal asymmetry, trait approach has been associated with greater left-frontal activity and trait avoidance has been associated with greater right-frontal activity. However, traits related to the supervisory control system have not been previously associated with frontal asymmetry. The current study sought to test whether trait positive urgency, measuring the tendency towards rash action in response to extreme positive emotional states, would relate to frontal alpha asymmetry. One hundred twenty-six individuals completed a measure of positive urgency and resting EEG recordings. Greater positive urgency was associated with greater relative left-frontal EEG activity. Source localization revealed that this relationship appeared to originate from reduced right-frontal activity in the inferior frontal gyrus. These results clarify that the link between frontal asymmetry and positive urgency is related to reduced right-frontal activity. Reduced right-frontal activity may be a potential neurobiological trait related to the supervisory control system.