Left Frontal Asymmetry Research Articles

The neural correlates of reinforcement sensitivity theory: A systematic review of the frontal asymmetry and spectral power literature.

The original Reinforcement Sensitivity Theory (oRST) proposes two systems of approach (BAS) and avoidance (BIS) motivation to underpin personality and behavior. The revised-RST (rRST) model separates avoidance motivation into passive (BIS; anxiety) and active (FFFS; fear) systems. Prior research has attempted to map RST onto lateralized frontal asymmetry to provide a neurophysiological marker of RST. The main aim is to examine the relationships of the o/rRST scales with trait (baseline) and state (manipulated through experimental paradigms) frontal asymmetry. A systematic review was conducted, resulting in 158 studies designated to neuroimaging research. In total, 54 studies were included in this review using either frontal asymmetry or spectral power. The results were split into three main categories: resting frontal alpha asymmetry (N = 23), emotional induction and state-related frontal alpha asymmetry (N = 20), and spectral analysis (N = 16). Findings indicated that BAS was associated with enhanced left frontal asymmetry at baseline and during state-related paradigms. Findings for BIS were more inconsistent, especially at rest, suggesting that BIS, in particular, may require active engagement with the environment. Only 9 of the 54 papers included used the revised RST model, highlighting the need for more rRST research.

Examining Conduct Problems in a Community Sample during Middle Childhood: The Role of Frontal EEG Asymmetry, Temperament, and Working Memory

Previous literature shows that aspects of temperament, executive functioning, and EEG frontal asymmetry are related to externalizing behaviors in children. We examined whether frontal EEG asymmetry measured at age 6 would moderate the impact of negative affectivity, attentional control, and working memory at age 6 on conduct problems at age 9. Behavioral tasks were given to assess children’s attentional control and working memory. Parents completed questionnaires about their children’s negative affectivity and conduct problems. Results showed that greater negative affectivity reported at age 6 predicted for more conduct problems reported at age 9, regardless of EEG frontal asymmetry. Lower levels of attentional control and working memory at age 6 predicted for more conduct problems reported at age 9 when children also exhibited greater left EEG frontal asymmetry, which has been linked to approach motivation. These findings illustrate the importance of assessing multiple intrinsic factors, both independent and interactive, that contribute to children’s conduct problems.

Frontal Alpha Asymmetry in Response to Stressor Moderates the Relation Between Parenting Hassles and Child Externalizing Problems.

Inequitable urban environments are associated with toxic stress and altered neural social stress processing that threatens the development of self-regulation. Some children in these environments struggle with early onset externalizing problems that are associated with a variety of negative long-term outcomes. While previous research has linked parenting daily hassles to child externalizing problems, the role of frontal alpha asymmetry (FAA) as a potential modifier of this relationship has scarcely been explored. The present study examined mother-child dyads, most of whom were living in low socioeconomic status households in an urban environment and self-identified as members of racial minority groups. Analyses focused on frustration task electroencephalography (EEG) data from 67 children (mean age = 59.0 months, SD = 2.6). Mothers reported the frequency of their daily parenting hassles and their child’s externalizing problems. Frustration task FAA moderated the relationship between parenting daily hassles and child externalizing problems, but resting FAA did not. More specifically, children with left frontal asymmetry had more externalizing problems as their mothers perceived more hassles in their parenting role, but parenting hassles and externalizing problems were not associated among children with right frontal asymmetry. These findings lend support to the motivational direction hypothesis and capability model of FAA. More generally, this study reveals how individual differences in lateralization of cortical activity in response to a stressor may confer differential susceptibility to child behavioral problems with approach motivation (i.e., left frontal asymmetry) predicting externalizing problems under conditions of parental stress.

Frontal Asymmetry as a Neural Correlate of Motivational Conflict

Motivational systems of approach, avoidance, and inhibition are fundamental to human behavior. While past research has linked approach motivation with greater relative left frontal asymmetry, many attempts to link avoidance motivation with greater relative right frontal asymmetry have been mixed. These mixed effects could be due to coactivation of the avoidance and behavioral inhibition system (BIS). Much recent evidence indicates that the behavioral inhibition system may be associated with greater relative right frontal activation. The current review examines evidence linking traits associated with the behavioral inhibition system with resting right frontal asymmetry. Other research links individual differences associated with the behavioral inhibition system with state changes in relative right frontal asymmetry. Moreover, activation of the behavioral inhibition system, but not activation of withdrawal motivation, increases greater relative right frontal asymmetry. Together, this work highlights the role of relative frontal asymmetry as a neural correlate in motivational conflict and helps to disentangle behavioral inhibition from avoidance motivation.

The relationship between habitual use and real-time emotion regulation strategies in adolescents: Evidence from frontal EEG asymmetry

Past research on emotion regulation has shown that cognitive reappraisal is a healthier and more effective emotion regulation strategy than expressive suppression. However, there are few studies in this field that combine real-time emotion regulation with the use of habitual emotion regulation strategies to observe the patterns of brain activity, and fewer studies focusing on adolescents. Frontal electroencephalography (EEG) asymmetry reflects the difference between brain activation in left and right frontal areas and is widely viewed as an effective biomarker of emotional reactivity and regulation. The present study investigated the asymmetry of the frontal EEG activity during adolescents' emotional regulation, and explored its relationship with adolescents’ habitual use of emotional regulation strategies. Habitual use of cognitive reappraisal and expressive suppression was measured with the emotion regulation questionnaire (ERQ). EEG was recorded from 54 adolescents (24 boys & 30 girls, Mage = 12.59), during the Reactivity and Regulation-Image Task. Results showed that adolescents who used cognitive reappraisal strategies more habitually exhibited greater left frontal asymmetry during real-time enhancement or reduction of negative emotions. In contrast, no significant correlation was found between habitual use of suppression and frontal alpha asymmetry. The results provide neurological evidence that, for adolescents, the use of habitual emotion regulation strategies may affect real-time emotion regulation, adolescents who use cognitive reappraisal more frequently are more capable or more prone to recruit appropriate brain regions in situations that need to regulate negative emotions. This reinforces the importance of the formation and use of correct emotion regulation habits for adolescents.

Shelf-based scarcity as a cue of luxuriousness: an application of psychophysiology

PurposeThe purpose of this paper is to examine the perception of luxuriousness as a novel underlying mechanism of the shelf-based scarcity effect by using both psychophysiological measures (Study 1) and self-reported measures (Study 2).Design/methodology/approachTwo within-subject experimental designs were conducted to examine the effects of low, medium and high stock depletion levels (i.e. shelf-based scarcity) on consumer responses. In Study 1, facial expression analysis was used to examine consumers’ liking, and left frontal asymmetry brainwaves were used to examine consumers’ approach motivation as a proxy for purchase intention. Study 2 extended the findings with self-reported measures.FindingsIn Study 1, perceived product luxuriousness was found to underlie the shelf-based scarcity effect on facial expressions and left frontal asymmetry brainwaves after controlling for other previously proposed mediators (i.e. product popularity and quality). The shelf-based scarcity effect is only observed between low vs high stock levels, whereas moderate stock level depletion does not evoke the shelf-based scarcity effect. Study 2 used self-reported measures to replicate the effect of shelf-based scarcity on product luxuriousness. However, the findings demonstrated the limitation of self-reported measures to identify a significant spill-over effect of perceived luxuriousness to attitude.Research limitations/implicationsExtending previous literature that relied heavily on self-reported measures, the current research used psychophysiological methods to uncover perceived luxuriousness as a novel underlying mechanism for the shelf-based scarcity effect. Thus, the findings are not only the first to provide psychophysiological evidence of the shelf-based scarcity effect but also to validate perceived luxuriousness as an underlying mechanism of the shelf-based scarcity effect.Practical implicationsThe current findings suggest that the shelf-based scarcity effect is only evoked by high (instead of moderate) levels of stock depletion. The study also shows that shelf-based scarcity does not necessarily signal product popularity, but instead it may serve as a cue of product luxuriousness. Adding to other manipulations of retail spaces that elicit luxury perception (e.g. artwork, sensory delight and themed store atmospherics), this implies that businesses are able to use shelf-based scarcity as a cue to enhance or complement the luxury image or the perception of the brand or product.Originality/valueThe current research is the first study to use psychophysiological techniques to examine perceived luxuriousness as an underlying mechanism of shelf-based scarcity. It also demonstrates that self-report measures are not sensitive to such an effect in comparison to psychophysiological techniques, explaining why perceived luxuriousness has not been previously found to be an underlying mechanism of shelf-based scarcity.

Frontal asymmetry: A novel biomarker for physical activity and sedentary behavior.

Past research has demonstrated that regular physical activity provides a myriad of physical, mental, and emotional benefits. The decision of whether to partake in physical activity (PA) or remain sedentary appears to be partially influenced by motivational and emotional systems. Research suggests left frontal alpha asymmetry is a neural marker of approach motivation. However, studies have not explored whether habitual levels of PA and sedentary behavior relate to this neurophysiological signal. Across two studies, individuals completed measures of habitual PA and sedentary behavior using the International Physical Activity Questionnaire-Short Form. Then, resting electroencephalography activity was recorded. Results of Study 1 (N=32, 72% women) indicated that more time spent sitting on both weekdays and weekend days were associated with less left frontal asymmetry (r = -.45, p = .027, and r = -.55, p = .005, respectively). Study 2 recruited a larger sample (N=96, 31% women) and investigated moderators. Greater levels of moderate (r = .27) and total (r = .29) PA were associated with greater left frontal asymmetry (ps < .05), and the relationship between sedentary behavior and less left frontal asymmetry was moderated by sex (weekday: β = .62, p = .011; weekend day: β = .41, p = .034). Our results suggest that left frontal asymmetry may be a novel neurophysiological marker for PA and sedentary behavior.

The effects of implicit evaluation of emotion regulation on electrical brain activity

Implicit evaluation of emotion regulation (IE-ER) refers to an implicit representation of individuals' attitudes about whether emotion should be regulated, and comprises positive (PIE-ER) and negative (NIE-ER) emotion regulation components. In this study we used the picture position decision task to investigate participants' electrical brain responses to both types of IE-ER. Electroencephalogram data were recorded simultaneously. Analysis of variance results show that the PIEER (vs. NIE-ER) group had significantly higher N1 amplitudes, shorter N1 latencies, and lower P1 amplitudes. The P1 amplitude in the left (vs. right) frontal brain region was significantly higher in both groups. In addition, as the PIE-ER (vs. NIE-ER) group had a greater ability to orient themselves to emotional stimuli, the cognitive resources they allocated to processing emotional stimuli decreased: Processing depth gradually became shallow, and emotion regulation elicited left frontal electrical asymmetry. Our findings provide a new understanding of unconscious emotion regulation, which may impact on physical and psychological intervention for the treatment of individuals' emotional problems and mental health, and well-being promotion.

O3. Genetic Variation in the Oxytocin System Impacts Infants’ Prefrontal Brain Asymmetry Responses to Emotional Faces

Experiencing and viewing emotional states has been linked to systematic changes in frontal brain asymmetry responses. In infants and adults, greater left frontal asymmetry indexes approach tendencies, whereas greater right frontal asymmetry reflects withdrawal tendencies. However, little is known about what factors contribute to individual variability in emotional brain processes, especially during infancy. Previous research has identified a single-nucleotide polymorphism on the CD38 gene (rs3796863) linked to autism spectrum disorder, differences in oxytocin release, and attention to emotional faces in young infants. We therefore examined whether CD38 impacts prefrontal brain asymmetry responses to emotional faces.

Shifts in frontal asymmetry underlying impulsive and controlled decision-making

The frontal cortices are asymmetrically activated in impulsive and inhibitory action. However, no past work has examined shifts in frontal asymmetric activation during active impulse control or risk-taking behavior. The current study examined impulsive and controlled behavior in a behavioral risk-taking task (Balloon Analogue Risk Task) under alcohol or neutral cue exposure while EEG was recorded. Results revealed activity shifted towards greater relative left frontal activation on alcohol trials with impulsive behavior (balloon explosion) driven by reduced activation of the right inferior frontal gyrus. In contrast, activity from the first half to the second half of alcohol trials with successful impulse control (cash out) localized to reduced activation of the left inferior frontal gyrus. These findings suggest that shifting of right or left frontal asymmetry in inhibitory or impulsive behaviors stem from activation of the inferior frontal gyrus and reveal the importance of examining shifts in neural activity during behavioral processes.

Trajectories of frontal brain activity and socio-emotional development in children.

Asymmetric frontal brain activity is thought to reflect individual differences in approach- and avoidance-oriented motivation and emotional experience. Using a prospective longitudinal design, the authors investigated whether trajectories of frontal electroencephalogram (EEG) asymmetry in children (Mage = 6.39 years at enrollment) predicted subjective, behavioral, and autonomic indices of socioemotional processes. Resting frontal EEG activity was measured across four separate repeated assessments spanning approximately 2 years. Children's EEG asymmetry across assessments was best characterized by two trajectories: a stable right frontal asymmetry class (48.65%), and a stable left frontal asymmetry class (51.35%). At visit 4, children in the stable right frontal asymmetry displayed more avoidance-related tendencies and children in the stable left frontal asymmetry class exhibited more approach-related tendencies across social, emotional, and autonomic measures. These findings suggest that developmental patterns of resting frontal brain activity across the early school years may underlie approach- and avoidance-related motivation and predict socio-emotional processes in some children.

Social modeling of eating mediated by mirror neuron activity: A causal model moderated by frontal asymmetry and BMI

The social modeling of eating effect refers to the consistently demonstrated phenomenon that individuals tend to match their quantity of food intake to their eating companion. The current study sought to explore whether activity within the mirror neuron system (MNS) mediates the social modeling of eating effect as a function of EEG frontal asymmetry and body mass index (BMI). Under the guise of rating empathy, 93 female undergraduates viewed a female video confederate “incidentally” consume either a low or high intake of chips while electroencephalogram (EEG) activity was recorded. Subsequent ad libitum chip consumption was quantified. A first- and second-stage dual moderation model revealed that frontal asymmetry and BMI moderated an indirect effect of model consumption on participants’ food consumption as mediated by MNS activity at electrode site C3, a3b3=−0.718, SE=0.365, 95% CI [−1.632, −0.161]. Left frontal asymmetry was associated with greater mu activity and a positive association between model and participant chip consumption, while right frontal asymmetry was associated with less mu activity and a negative association between model and participant consumption. Across all levels of frontal asymmetry, the effect was only significant among those with a BMI at the 50th percentile or lower. Thus, among leaner individuals, the MNS was demonstrated to mediate social modeling of eating, as moderated by frontal asymmetry. These findings are integrated within the normative account of social modeling of eating. It is proposed that the normative framework may benefit from consideration of both conscious and unconscious operation of intake norms.

Frontal EEG asymmetry and later behavior vulnerability in infants with congenital visual impairment

ObjectiveYoung children with congenital visual impairment (VI) are at increased risk of behavioral vulnerabilities. Studies on ‘at risk’ populations suggest that frontal EEG asymmetry may be associated with behavioral risk. We investigated frontal asymmetry at 1year (Time 1), behavior at 2years (Time 2) and their longitudinal associations within a sample of infants with VI. Frontal asymmetry in the VI sample at 1year was also compared cross-sectionally to an age-matched typically sighted (TS) group. MethodsAt Time 1, 22 infants with VI and 10 TS infants underwent 128-channel EEG recording. Frontal asymmetry ratios were calculated from power spectral density values in the alpha frequency band. At Time 2, Achenbach Child Behavior Checklist data was obtained for the VI sample. Results63.6% of the VI sample and 50% of the TS sample showed left frontal asymmetry; no significant difference in frontal asymmetry was found between the two groups. 22.7% of the VI sample had subclinical to clinical range ‘internalizing’ behavior difficulties. Greater left frontal asymmetry at one year was significantly associated with greater emotionally reactive scores at two years within the VI sample (r=0.50, p=0.02). ConclusionsLeft frontal asymmetry correlates with later behavior risk within this vulnerable population. SignificanceThese findings make an important first contribution regarding the utility of frontal EEG asymmetry as a method to investigate risk in infants with VI.

The relation of hedonic hunger and restrained eating to lateralized frontal activation

Asymmetrical alpha activation in the prefrontal cortex (frontal asymmetry) in electroencephalography (EEG) has been related to eating behavior. Prior studies linked dietary restraint with right frontal asymmetry [1] and disinhibition with left frontal asymmetry [2]. The current study simultaneously assessed restrained eating and hedonic hunger (drive for food reward in the absence of hunger) in relation to frontal asymmetry. Resting-state EEG and measures of restrained eating (Revised Restraint Scale; RRS) and hedonic hunger (Power of Food Scale; PFS) were assessed in 61 non-obese adults. Individually, hedonic hunger predicted left asymmetry. However, PFS and RRS were correlated (r=0.48, p<0.05) and there was a significant interaction between PFS and RRS on frontal asymmetry, p<0.01. Results indicated that those high in hedonic hunger exhibited left asymmetry irrespective of RRS scores; among those low in PFS, only those high in RRS showed right asymmetry. Results were consistent with literature linking avoidant behaviors (restraint) with right-frontal asymmetry and approach behaviors (binge eating) with left-frontal asymmetry. It appears that a strong drive toward palatable foods predominates at a neural level even when restraint is high. Findings suggest that lateralized frontal activity is an indicator of motivation both to consume and to avoid consuming highly palatable foods.

Maternal Frontal EEG Asymmetry and Chronic Stressors Moderate the Link between Child Conduct Problems and Maternal Negativity.

Frontal EEG asymmetry is associated with individual differences in positive/negative emotionality and approach/avoidance tendencies. The current study examined the moderating role of maternal resting frontal EEG asymmetry on the link between child behavior problems and maternal harsh parenting, within the context of differing degrees of chronic family stressors (father unemployment, single parenthood, caring for multiple children, and household chaos). The sample included 121 mother-child pairs. Results showed that stressors and frontal EEG asymmetry together moderated the link. Child problem behaviors were moderately associated with greater maternal negativity for mothers with right frontal asymmetry, or mothers who experienced more stressors. However, no association existed between child behavior problems and maternal negativity for mothers with few stressors and left frontal asymmetry. The findings implicate transactions between household stress and a psychophysiological indicator of maternal emotional reactivity and mothers' approach/avoidance tendencies, in the etiology of parental negativity toward challenging child behaviors.

Are Orchids Left and Dandelions Right? Frontal Brain Activation Asymmetry and Its Sensitivity to Developmental Context

To clarify long-standing conceptual and empirical inconsistencies in models describing the relation between frontal brain asymmetry and emotion, we tested a theory of biological sensitivity to context. We examined whether asymmetry of alpha activation in frontal brain regions, as measured by resting electroencephalography, is sensitive to early developmental contexts. Specifically, we investigated whether frontal asymmetry moderates the association between birth weight and adult outcomes. Adults with left frontal asymmetry (LFA) who were born at extremely low birth weight exhibited high levels of attention problems and withdrawn behaviors in their 30s, whereas normal-birth-weight adults with LFA had low levels of these problem behaviors. Adults with right frontal asymmetry (RFA) displayed a relatively moderate amount of problem behavior regardless of birth weight. Our findings suggest that LFA is associated with sensitivity to developmental context and may help explain why LFA is associated with both positive and negative outcomes, whereas RFA seems to be associated with a more canalized process in some contexts.

Resting frontal EEG asymmetry in children: Meta‐analyses of the effects of psychosocial risk factors and associations with internalizing and externalizing behavior

Asymmetry of frontal cortical electroencephalogram (EEG) activity in children is influenced by the social environment and considered a marker of vulnerability to emotional and behavioral problems. To determine the reliability of these associations, we used meta-analysis to test whether variation in resting frontal EEG asymmetry is consistently associated with (a) having experienced psychosocial risk (e.g., parental depression or maltreatment) and (b) internalizing and externalizing behavior outcomes in children ranging from newborns to adolescents. Three meta-analyses including 38 studies (N = 2,523) and 50 pertinent effect sizes were carried out. The studies included in the analyses reported associations between frontal EEG asymmetry and psychosocial risk (k = 20; predominantly studies with maternal depression as the risk factor) as well as internalizing (k = 20) and externalizing (k = 10) behavior outcomes. Psychosocial risk was significantly associated with greater relative right frontal asymmetry, with an effect size of d = .36 (p < .01), the effects being stronger in girls. A non-significant relation was observed between right frontal asymmetry and internalizing symptoms (d = .19, p = .08), whereas no association between left frontal asymmetry and externalizing symptoms was observed (d = .04, p = .79). Greater relative right frontal asymmetry appears to be a fairly consistent marker of the presence of familial stressors in children but the power of frontal asymmetry to directly predict emotional and behavioral problems is modest.

Mindfulness-Based Stress Reduction for Older Adults: Effects on Executive Function, Frontal Alpha Asymmetry and Immune Function

Background/Aims: Mindfulness-based stress reduction (MBSR) has enhanced cognition, positive emotion, and immunity in younger and middle-aged samples; its benefits are less well known for older persons. Here we report on a randomized controlled trial of MBSR for older adults and its effects on executive function, left frontal asymmetry of the EEG alpha band, and antibody response. Methods: Older adults (n = 201) were randomized to MBSR or waiting list control. The outcome measures were: the Trail Making Test part B/A (Trails B/A) ratio, a measure of executive function; changes in left frontal alpha asymmetry, an indicator of positive emotions or approach motivation; depression, mindfulness, and perceived stress scores, and the immunoglobulin G response to a protein antigen, a measure of adaptive immunity. Results: MBSR participants had a lower Trails B/A ratio immediately after intervention (p < 0.05); reduced shift to rightward frontal alpha activation after intervention (p = 0.03); higher baseline antibody levels after intervention (p < 0.01), but lower antibody responses 24 weeks after antigen challenge (p < 0.04), and improved mindfulness after intervention (p = 0.023) and at 21 weeks of follow-up (p = 0.006). Conclusions: MBSR produced small but significant changes in executive function, mindfulness, and sustained left frontal alpha asymmetry. The antibody findings at follow-up were unexpected. Further study of the effects of MBSR on immune function should assess changes in antibody responses in comparison to T-cell-mediated effector functions, which decline as a function of age.

The Effects of Sucrose Consumption on Left-Frontal Asymmetry and Anger in Persons with Fibromyalgia Syndrome

ABSTRACT.Objectives: Previous studies suggest that a carbohydrate-restricted diet ameliorates chronic and idiopathic post-prandial [PP] mood symptoms in persons with fibromyalgia syndrome [FMS]. These studies, however, shed no light on the PP effects of carbohydrate on mood and its electroencephalographic correlates. The present study measured the effects of sucrose on electroencephalogram [EEG] and mood self-report measures in persons with FMS and age-matched healthy normal controls [HNC].Methods: The present investigation sought to determine the relationships between reported mood, relative left-frontal EEG asymmetry [rLFA] in the alpha band, and blood glucose at baseline and four PP epochs following ingestion of pure sucrose in female participants with FMS [N = 8] and HNC [N = 10].Results: The FMS and HNC showed equivalent patterns of blood glucose throughout the study, but FMS patients showed elevated levels of depression, anger, and other indicators of distress at all time points. An interaction emer...

Stress-induced asymmetric frontal brain activity and aggression risk.

Impersonal stressors, not only interpersonal provocation, can instigate aggression through an associative network linking negative emotions to behavioral activation (L. Berkowitz, 1990). Research has not examined the brain mechanisms that are engaged by different types of stress and serve to promote hostility and aggression. The present study examined whether stress exposure elicits more left than right frontal brain activity implicated in behavioral approach motivation and whether this lateralized brain activity predicts stress-induced aggression and hostile/aggressive tendencies. Results showed that (a) participants in the impersonal (assigned to stress by a computer) and interpersonal (assigned to stress by a provoking confederate) stress conditions both showed more left than right frontal electroencephalogram activity after condition assignment and stress exposure and (b) the 2 stress groups exhibited subsequent increases in aggression relative to the no-stress group. Importantly, left frontal asymmetry in response to stress exposure predicted increases in subsequent aggressive behavior, a finding that did not emerge in the no-stress condition. Thus, both the interpersonal and impersonal stressors impacted state changes in brain activity related to behavioral approach, suggesting that stress reactivity involving approach activation represents risk for behavioral dysregulation.