Greater Relative Left Frontal Activity Research Articles

Frontal alpha asymmetry: A potential biomarker of approach-withdrawal motivation towards pain.

Pain-related catastrophising is a maladaptive coping strategy known to have a strong influence on clinical pain outcomes and treatment efficacy. Notwithstanding, little is known about its neurophysiological correlates. There is evidence to suggest catastrophising is associated with resting-state EEG frontal alpha asymmetry (FAA) patterns reflective of greater relative right frontal activity, which is known to be linked to withdrawal motivation and avoidance of aversive stimuli. The present study aims to investigate whether such a relationship occurs in the situational context of experimental pain. A placebo intervention was also included to evaluate effects of a potential pain-relieving intervention on FAA. 35 participants, including both chronic pain patients and healthy subjects, completed the Pain Catastrophising Scale (PCS) questionnaire followed by EEG recordings during cold pressor test (CPT)-induced tonic pain with or without prior application of placebo cream. There was a negative correlation between FAA and PCS-subscale helplessness scores, but not rumination or magnification, during the pre-placebo CPT condition. Moreover, FAA scores were shown to increase significantly in response to pain, indicative of greater relative left frontal activity that relates to approach-oriented behaviours. Placebo treatment elicited a decrease in FAA in low helplessness scorers, but no significant effects in individuals scoring above the mean on PCS-helplessness. These findings suggest that, during painful events, FAA may reflect the motivational drive to obtain reward of pain relief, which may be diminished in individuals who are prone to feel helpless about their pain. This study provides valuable insights into biomarkers of pain-related catastrophising and prospects of identifying promising targets of brain-based therapies for chronic pain management.

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.

Regulatory behavior and frontal activity: Considering the role of revised-BIS in relative right frontal asymmetry.

Essential to human behavior are three core personality systems: approach, avoidance, and a regulatory system governing the two motivational systems. Decades of research has linked approach motivation with greater relative left frontal-cortical asymmetry. Other research has linked avoidance motivation with greater relative right frontal-cortical asymmetry. However, past work linking withdrawal motivation with greater relative right frontal asymmetry has been mixed. The current article reviews evidence suggesting that activation of the regulatory system (revised Behavioral Inhibition System [r-BIS]) may be more strongly related to greater relative right frontal asymmetry than withdrawal motivation. Specifically, research suggests that greater activation of the r-BIS is associated with greater relative right frontal activity, and reduced r-BIS activation is associated with reduced right frontal activity (greater relative left frontal activity). We review evidence examining trait and state frontal activity using EEG, source localization, lesion studies, neuronal stimulation, and fMRI supporting the idea that r-BIS may be the core personality system related to greater relative right frontal activity. In addition, the current review seeks to disentangle avoidance motivation and r-BIS as substrates of relative right frontal asymmetry.

Regulatory control and impulsivity relate to resting frontal activity.

Gray’s Reinforcement Sensitivity Theory (RST) asserts three core personality systems: the behavioral approach system (BAS), the fight-flight-freeze system (FFFS) and the revised behavioral inhibition system (r-BIS). Past models of frontal activity link greater relative left frontal activity with Carver and White’s (1994) BAS scale and trait impulsivity and greater relative right frontal activity with Carver and White’s (1994) BIS scale. However, the original BIS scale assesses both FFFS and r-BIS. Past work linking the BIS scale and right frontal activity does not indicate which system is related to right frontal activity. The current study (n = 182) examined frontal asymmetric activity with personality traits associated with approach (BAS), withdrawal (FFFS-Fear), behavioral inhibition (BIS-Anxiety) and impulsivity (UPPS-P). Resting frontal cortical activity was recorded using electroencephalography (EEG), and the traditional alpha band was examined. Greater BIS-Anxiety related to greater relative right frontal activity. Impulsivity related to less relative right frontal activity. BAS and FFFS-Fear (approach and withdrawal motivation) did not relate to asymmetric frontal activity. Regulatory control processes associated with r-BIS and impulsivity, rather than withdrawal motivation associated with FFFS, may be more closely related to right frontal activity.

Frontal asymmetry and alcohol cue reactivity: Influence of core personality systems.

Greater left frontal activation appears to be a measure of appetitive reactivity for desired stimuli, such as alcohol cues. However, inconsistencies in past research examining frontal asymmetry to appetitive stimuli suggest that individual differences strongly influence frontal asymmetry to appetitive stimuli. Because core personality systems of approach, avoidance, and supervisory control play a fundamental role in directing alcohol behavior, the current study sought to determine which core system would influence asymmetric frontal activation to alcohol cues. Results revealed that greater trait impulsivity (reduced functioning of the supervisory control system) is related to greater relative left frontal activation in response to alcohol cues. Approach motivation and avoidance motivation were unrelated to greater relative left frontal activation in response to alcohol cues. These results suggest that decreased activation of the supervisory control system (increased trait impulsivity) is responsible for appetitive reactivity to alcohol cues.

Neurophysiological markers of multiple facets of impulsivity

Human behavior is influenced by three core personality systems: approach, avoidance, and supervisory control. The supervisory control system is inversely related to impulsivity. Although past research has related some aspects of impulsivity to frontal hemispheric asymmetry, impulsivity as a multi-faceted construct has not been studied in relation with frontal asymmetry. In addition, past work has potentially confounded impulsivity with approach-motivation. In the current study, greater relative left frontal activity was related to multiple facets of impulsivity: negative urgency, lack of premeditation, lack of perseverance, and positive urgency. Regressing both positive and negative urgency on frontal asymmetry revealed that approach-related positive urgency related to greater left frontal activity, but withdrawal-related negative urgency marginally related to greater right frontal activity. These results suggest that impulsivity, independent of affective valence, relates to greater left frontal activity. When controlling for trait approach motivation, the relationship between impulsivity and left frontal activity is unchanged.

Emotional–motivational responses predicting choices: The role of asymmetrical frontal cortical activity

We examined (a) how emotional attachment to a choice option as indexed by state-related changes in electroencephalographic (EEG) asymmetry over the prefrontal cortex and electrodermal activity predicts choices and mediates the endowment effect and (b) the emotional–motivational responses to trade-off choices. Thirty-eight participants made choices between three 4-product packages, in which the frequency of each of the products varied. Greater relative left frontal activation and high peak skin conductance level (SCL) elicited by a previously selected choice option predicted a stronger endowment effect, suggesting that approach motivation and emotional attachment mediate the endowment effect. Not selecting a choice option with high emotional attachment elicited relatively greater right hemisphere activation, supporting also the role of loss aversion in the endowment effect. In addition, high trade-off difficulty was associated with increased withdrawal motivation (or less approach motivation) and negatively valenced arousal. We conclude with a discussion of practical implications of our findings.

Unilateral hand contractions produce motivational biases in social economic decision making.

Unilateral hand contractions have been shown to induce relative activation of the contralateral hemisphere, which is in turn associated with distinct motivational states. Specifically, right hand contraction increases relative left activation and promotes an approach state, and left hand contractions promote relative right activation and withdrawal states. Using the same hand clenching technique, the present study extends this research to examine the incidental role of motivational tendency on interactive economic decision making. A total of 75 right-handed participants were randomly assigned to 1 of 3 conditions, including withdrawal/left-hand contractions, approach/right-hand contractions, and control/no contraction. Participants completed 2 well-known economic tasks, namely the Ultimatum Game (UG), Dictator Game (DG). In the UG, we found that relative to individuals in the withdrawal condition, those in the approach (right-hand contraction) condition made higher monetary offers to human partners who could either accept or reject these offers. Moreover, those in the approach condition rejected significantly more unfair offers from human partners. This study provides the first evidence that hemispheric activation, using unilateral muscle contractions, may play a causal role in biasing social economic decision making. Overall, there results suggest that greater relative left frontal activation promotes reward-maximizing strategies, consistent with an approach motivation, and relative right frontal activation may decrease such strategic tendencies.

Affective motivational direction drives asymmetric frontal hemisphere activation

Decades of research have shown that the left- and right-frontal cortical regions are asymmetrically involved in affective processing. Specifically, this past work has demonstrated that greater left-frontal activation is related to positive-approach, and greater right-frontal activation is related to negative-withdrawal. However, much of this past work confounded motivation and affective valence. The current experiment sought to illuminate whether frontal asymmetry is related to motivation or affective valence by examining frontal-lateralized late positive potentials (f-LPPs) and frontal cortical alpha power activation to approach-positive, approach-negative, and withdrawal-negative affects in the same participants. Results revealed that f-LPPs to approach-positive and approach-negative pictures were larger in left- (vs. right-) frontal regions, whereas f-LPPs to withdrawal-negative pictures did not differ between frontal regions. In addition, midline LPPs to approach-positive and approach-negative pictures related to greater left-frontal cortical activation. Together, these results suggest that greater relative left-frontal activation is associated with positive and negative approach-motivated states in the same participants. More broadly, these results are consistent with conceptual models that asymmetric hemisphere activation is related to motivational direction, rather than affective valence.

Neural and behavioral associations of manipulated determination facial expressions

Past research associated relative left frontal cortical activity with positive affect and approach motivation, or the urge to move toward a stimulus. Less work has examined relative left frontal activity and positive emotions ranging from low to high approach motivation, to test whether positive affects that differ in approach motivational intensity influence relative left frontal cortical activity. Participants in the present experiment adopted determination (high approach positive), satisfaction (low approach positive), or neutral facial expressions while electroencephalographic (EEG) activity was recorded. Next, participants completed a task measuring motivational persistence behavior and then they completed self-report emotion questionnaires. Determination compared to satisfaction and neutral facial expressions caused greater relative left frontal activity relative to baseline EEG recordings. Facial expressions did not directly influence task persistence. However, relative left frontal activity correlated positively with persistence on insolvable tasks in the determination condition. These results extend embodiment theories and motivational interpretations of relative left frontal activity.

Asymmetric frontal brain activity and parental rejection predict altruistic behavior: Moderation of oxytocin effects

Asymmetric frontal brain activity has been widely implicated in reactions to emotional stimuli and is thought to reflect individual differences in approach–withdrawal motivation. Here, we investigate whether asymmetric frontal activity, as a measure of approach–withdrawal motivation, also predicts charitable donations after a charity’s (emotion-eliciting) promotional video showing a child in need is viewed, in a sample of 47 young adult women. In addition, we explore possibilities for mediation and moderation, by asymmetric frontal activity, of the effects of intranasally administered oxytocin and parental love withdrawal on charitable donations. Greater relative left frontal activity was related to larger donations. In addition, we found evidence of moderation: Low levels of parental love withdrawal predicted larger donations in the oxytocin condition for participants showing greater relative right frontal activity. We suggest that when approach motivation is high (reflected in greater relative left frontal activity), individuals are generally inclined to take action upon seeing someone in need and, thus, to donate money to actively help out. Only when approach motivation is low (reflected in less relative left/greater relative right activity) do empathic concerns affected by oxytocin and experiences of love withdrawal play an important part in deciding about donations.

Frontal EEG Activation Asymmetry Reflects Cognitive Biases in Anxiety: Evidence from an Emotional Face Stroop Task

Electroencephalography (EEG) has been extensively used in studies of the frontal asymmetry of emotion and motivation. This study investigated the midfrontal EEG activation, heart rate and skin conductance during an emotional face analog of the Stroop task, in anxious and non-anxious participants. In this task, the participants were asked to identify the expression of calm, fearful and happy faces that had either a congruent or incongruent emotion name written across them. Anxious participants displayed a cognitive bias characterized by facilitated attentional engagement with fearful faces. Fearful face trials induced greater relative right frontal activation, whereas happy face trials induced greater relative left frontal activation. Moreover, anxiety specifically modulated the magnitude of the right frontal activation to fearful faces, which also correlated with the cognitive bias. Therefore, these results show that frontal EEG activation asymmetry reflects the bias toward facilitated processing of fearful faces in anxiety.

Predicting affective responses to exercise using resting EEG frontal asymmetry: Does intensity matter?

Affective responses to exercise may be important for improving adherence to regular programs of exercise. The present study sought to determine whether resting frontal EEG asymmetry, an individual difference measure of affective style, is predictive of affective responses to exercise performed at distinct intensities standardized relative to a metabolic landmark (i.e., the ventilatory threshold, VT). Resting EEG was collected from 30 participants and used to predict affective responses following treadmill running at three exercise intensities: below-VT, at-VT, and above-VT. Affect was assessed [via Activation–Deactivation Adjective Check List, yielding measures of Energetic Arousal (EA) and Tense Arousal (TA)] before, immediately following exercise, after 5min cool down, and 10 and 20min post-cool down. Resting mid-frontal asymmetry (F4–F3) significantly predicted EA immediately following below-VT exercise; resting lateral frontal asymmetry (F8–F7) predicted EA at 20min post-cool down. Resting mid-frontal asymmetry predicted in EA immediately following and following cool down in above-VT exercise. As a whole, frontal asymmetry was predictive of affective responses following exercise, namely greater relative left frontal activity predicting lower EA. This was opposite to the predictions of the valenced motivation model, but may provide some support for the motivation direction model. This is based on the fact that low EA could be indicative of approach motivation, especially at higher exercise intensities.

The Relationship Between Frontal Brain Asymmetry and Exercise Addiction

Previous research on the causes of exercise addiction has focused primarily on the relationships among personality traits, social influences, and disordered eating ( Bamber, Cockerill, & Carroll, 2000 ; Beals, 2004 ). Few studies, however, have examined the psychophysiological nature of exercise addiction. In a related area of research in which brain activity has been related to affect and mood, results show that frontal asymmetry, as measured by electroencephalogram (EEG), is associated with negative emotions. More specifically, greater activity at right frontal electrode sites is found among individuals suffering from negative affect and depression. Because a defining feature of exercise addiction is the use of exercise to control negative mood states, it is expected that those with exercise addiction exhibit different frontal activity. This study explores the hypothesized relationship between exercise addiction and the level of baseline frontal activity asymmetry, as measured by EEG. Regularly active women (n = 28, M age = 32.43, SD = 10.89) were recruited to participate in the study. Exercise addiction status was determined by the Exercise Addiction Inventory (EAI) ( Terry, Szabo, & Griffiths, 2004 ). After completing the EAI, each participant took part in an EEG session consisting of eight 1-min resting trials, four with eyes open, and four with eyes closed, presented in counterbalanced order. Electrodes were applied to the left and right frontal sites (F3 and F4). A regression analysis, predicting exercise addiction from frontal asymmetry, was significant, F(1, 27) = 6.4, p < .05, and indicated that greater relative left frontal activity with higher exercise addiction scores. There may be a link between frontal asymmetry, as an indicator of negative emotions, and exercise addiction in women.

Frontal EEG asymmetry and sensation seeking in young adults

Sensation seeking has been characterized as a desire to seek novel, intense sensations, and the willingness to take risks in pursuing them. In two separate studies of young adults, we examined the relation between measures of sensation seeking and the pattern of resting frontal EEG asymmetry, thought to reflect a biological predisposition to approach new experiences. As predicted, high sensation seeking was related to a greater relative left frontal activity at rest in both studies, which may be specific to men. How greater relative left frontal cortical activity at rest is related to a tendency to engage in sensation-seeking and risky behaviors is discussed.

The role of asymmetrical frontal cortical activity in aggression

Aggression correlates with relatively greater left than right frontal electroencephalographic activity (inverse of EEG alpha power). The present experiment extends this research by manipulating frontal asymmetry and examining its effect on aggression. Participants were assigned to increase left frontal activation or increase right frontal activation by contracting their contralateral hand. They then received insulting feedback and played a game in which they could aggress toward the person who insulted them. Right-hand contractions caused greater left than right central and frontal activation and aggression as compared to left-hand contractions. Within the right-hand contraction condition, greater relative left frontal activity was associated with greater aggression.

Emotion and resilience: A multilevel investigation of hemispheric electroencephalogram asymmetry and emotion regulation in maltreated and nonmaltreated children

The current study was a multilevel investigation of resilience, emotion regulation, and hemispheric electroencephalogram (EEG) asymmetry in a sample of maltreated and nonmaltreated school age children. It was predicted that the positive emotionality and increased emotion regulatory ability associated with resilient functioning would be associated with relatively greater left frontal EEG activity. The study also investigated differences in pathways to resilience between maltreated and nonmaltreated children. The findings indicated that EEG asymmetry across central cortical regions distinguished between resilient and nonresilient children, with greater left hemisphere activity characterizing those who were resilient. In addition, nonmaltreated children showed greater left hemisphere EEG activity across parietal cortical regions. There was also a significant interaction between resilience, maltreatment status, and gender for asymmetry at anterior frontal electrodes, where nonmaltreated resilient females had greater relative left frontal activity compared to more right frontal activity exhibited by resilient maltreated females. An observational measure of emotion regulation significantly contributed to the prediction of resilience in the maltreated and nonmaltreated children, but EEG asymmetry in central cortical regions independently predicted resilience only in the maltreated group. The findings are discussed in terms of their meaning for the development of resilient functioning.

Regional brain activity and strenuous exercise: Predicting affective responses using EEG asymmetry

Previous research using the model proposed by Davidson has shown that resting frontal electroencephalographic (EEG) asymmetry can predict affective responses to aerobic exercise at moderate intensities. Specifically, greater relative left frontal activity has been shown to predict positive affect (i.e., energy) following exercise. The purpose of this study was to determine if resting frontal EEG asymmetry would predict affective responses following strenuous exercise. Thirty participants (13 women, 17 men) completed a maximal graded exercise test on a treadmill. EEG was recorded prior to exercise. Affect was measured by the Activation Deactivation Adjective Check List prior to the graded exercise test, immediately following, 10 and 20-min following exercise. Greater relative left frontal activity predicted tiredness and calmness during recovery from exercise, but not tension or energy. Tiredness and calmness following exercise covaried, suggesting that tiredness following exercise might not have been linked with displeasure. These findings offer further support for the link between EEG asymmetry and affective responses to exercise.

Anterior EEG asymmetries and opponent process theory

The opponent process theory of emotion [Solomon, R.L., and Corbit, J.D. (1974). An opponent-process theory of motivation: I. Temporal dynamics of affect. Psychological Review, 81, 119–143.] predicts a temporary reversal of emotional valence during the recovery from emotional stimulation. We hypothesized that this affective contrast would be apparent in asymmetrical activity patterns in the frontal lobes, and would be more apparent for left frontally active individuals. The present study tested this prediction by examining EEG asymmetries during and after blocked presentations of aversive pictures selected from the International Affective Picture System (IAPS). 12 neutral images, 12 aversive images, and 24 neutral images were presented in blocks. Participants who were right frontally active at baseline did not show changes in EEG asymmetry while viewing aversive slides or after cessation. Participants left frontally active at baseline, however, exhibited greater relative left frontal activity after aversive stimulation than before stimulation. Asymmetrical activity patterns in the frontal lobes may relate to affect regulatory processes, including contrasting opponent after-reactions to aversive stimuli.

Frontal EEG asymmetry and premenstrual dysphoric symptomatology.

Resting frontal electroencephalographic (EEG) asymmetry has been hypothesized to tap a diathesis toward depression or other emotion-related psychopathology. Frontal EEG asymmetry was assessed in college women who reported high (n = 12) or low (n = 11) levels of premenstrual negative affect. Participants were assessed during both the follicular and the late luteal phases of the menstrual cycle. Women reporting low premenstrual dysphoric symptomatology exhibited greater relative left frontal activity at rest than did women high in premenstrual dysphoric symptomatology, an effect that was not qualified by phase of cycle. Although women with extreme levels of symptomatology were assessed, the question of whether such symptoms qualified for premenstrual dysphoric disorder criteria was not assessed. These results are consistent with a diathesis-stress model for premenstrual dysphoric symptomatology.