Greater Relative Left Frontal EEG Research Articles

Right frontal brain activity at rest in the early 20s predicts threat-related bias ten years later among extremely low birth weight survivors

Exposure to early adversity is known to shape brain-behavior relations, which in turn can lead to hypersensitivity to threat and an increased risk of developing a range of psychopathologies. To date, much of the work in this area has considered exposure to negative post-natal events (e.g., maltreatment) in shaping these relations in humans. Here we examined the influence of prenatal adversity in the form of a suboptimal intra-uterine environment (i.e., being born at extremely low birth weight; [ELBW i.e., < 1000 g]). ELBW babies are the tiniest and most at-risk infants and are known to be at risk for internalizing problems (e.g., depression and anxiety) from childhood through early adulthood. However, we know relatively little about the mechanism(s) underlying this risk. Using the oldest known prospectively followed cohort of ELBW survivors, we examined associations among birth weight status, individual differences in frontal brain electrical activity (EEG) at rest (a marker of affective style) at age 22−26 years, and threat-related biases to angry faces (using the dot probe task) at 30−35 years of age. We found that among ELBW adults, those displaying greater relative right frontal EEG activity at rest exhibited greater vigilance to angry faces than those exhibiting greater relative left frontal EEG activity (n = 34, r = -0.40, p = .02). This pattern was not observed among normal birth weight (NBW) control participants (n = 47, r = .08, p > .05). As well, the relation between frontal EEG asymmetry and vigilance to angry faces was stronger for the ELBW group versus the NBW group (z = -2.21, p = .03). These findings suggest that exposure to significant prenatal adversity may have long-term programming effects on biological and cognitive systems associated with emotion regulatory processes in the fourth decade of life. We speculate that these vulnerabilities may contribute to making some ELBW survivors susceptible to psychopathology.

Frontal Brain Asymmetry and the Trajectory of Shyness Across the Early School Years.

Although resting right frontal electroencephalogram (EEG) asymmetry has been linked to avoidance and withdrawal-related behaviors such as shyness in previous cross-sectional studies, relatively little research has examined the influence of frontal brain electrical activity on the development of shyness in children using a prospective, longitudinal study design. Here, we tested whether resting frontal EEG asymmetry predicted the trajectory of children's shyness across five assessments. Children were enrolled in the study during the summer prior to grade 1 (N = 37; Mage = 6.39years, S.D. = 0.15years), at which time resting frontal EEG activity and maternal report of children's shyness were collected. Mothers then reported on their child's shyness over another four follow-up assessments, spanning 2years (winter of grade 1, summer prior to grade 2 entry, winter of grade 2, and summer prior to grade 3). Growth curve analysis revealed that children displaying greater relative right frontal EEG activity had lower levels of shyness relative to children exhibiting greater relative left frontal EEG activity at study enrollment (i.e., age 6), but displayed statistically significant linear increases in shyness across time, with the highest levels of shyness by the summer prior to grade 3 (i.e., age 8). There was, however, no relation between left frontal EEG asymmetry and change in shyness across time. These preliminary findings suggest that right frontal EEG asymmetry may reflect a biological diathesis for the growth of shyness during the early school years.

Asymmetrical frontal cortical activity associated with differential risk for mood and anxiety disorder symptoms: An RDoC perspective

The recently launched NIMH Research Domain Criteria (RDoC) initiative aims to examine the relationship between core biobehavioral dimensions and symptom profiles that either cut across traditional disorder categories or that are unique to specific clinical phenomenon. A biobehavioral construct that has received considerable attention and that is directly relevant to the Positive Valence Systems domain of the RDoC initiative is approach motivation. One way approach motivation is frequently operationalized is left versus right frontal electroencephalographic (EEG) activity, with greater relative left frontal EEG activity reflecting increased approach motivation and decreased relative left frontal EEG activity reflecting decreased approach motivation or increased withdrawal tendencies. The objective of the present review paper is to examine the relationship between relative left frontal EEG activity and mood and anxiety related symptoms from an RDoC perspective. We first provide an overview of the approach–withdrawal motivational model of frontal EEG asymmetry. Second, we review evidence that relative left frontal EEG activity is associated with a differential risk for unipolar depression versus bipolar disorder. Third, and in line with the mission statement of the RDoC, we move beyond considering mood and anxiety disorders as unitary constructs or homogenous disorders and instead propose that individual differences in relative left frontal EEG activity may be uniquely associated with specific symptom clusters of depression (i.e., anhedonia), hypomania/mania (i.e., symptoms characterized by excessive approach motivation), and anxiety (i.e., anxious apprehension versus anxious arousal). Identifying the relationship between relative left frontal EEG activity and specific mood and anxiety-related symptom clusters has important implications for clinical science, assessment, and treatment.

Instrumental and vocal music effects on EEG and EKG in neonates of depressed and non-depressed mothers

Neonates (M age = 16 days) born to depressed and non-depressed mothers were randomly assigned to hear an audiotaped lullaby of instrumental music with vocals or without vocals. Neonatal EEG and EKG were recorded for 2 min (baseline) of silence and for 2 min of one or the other music presentation. Neonates of non-depressed mothers showed greater relative right frontal EEG asymmetry to both types of music, suggesting a withdrawal response. Neonates of depressed mothers on the other hand showed greater relative left frontal EEG asymmetry to the instrumental without vocal segment, suggesting an approach response, and greater relative right frontal EEG asymmetry to the instrumental with vocal segment, suggesting a withdrawal response. Heart rate decelerations occurred following the music onset for both groups of infants, however, compared to infants of non-depressed mothers, infants of depressed mothers showed a delayed heart rate deceleration, suggesting slower processing and/or delayed attention. These findings suggest that neonates of depressed and non-depressed mothers show different EKG and EEG responses to instrumental music with versus without vocals.

Withdrawn and intrusive maternal interaction style and infant frontal EEG asymmetry shifts in infants of depressed and non-depressed mothers

The effects of maternal interaction style (intrusive/withdrawn) on the development of brain electrical activity were studied in infants of depressed and non-depressed mothers shortly after birth and again at 3–6 months of age. Infants of depressed mothers exhibited significantly greater relative right frontal EEG activation than infants of non-depressed mothers. Infants of depressed withdrawn mothers exhibited greater relative right frontal EEG activation than infants of depressed intrusive mothers. Furthermore, while infants of depressed mothers with intrusive interaction styles showed a shift towards greater relative left frontal EEG activation from birth to 3–6 months, infants of depressed mothers with withdrawn interaction styles showed a shift towards greater relative right frontal EEG activation.

Individual differences in anterior EEG asymmetry between high and low defensive individuals during a rumination/distraction task

The current study examined how reactions to a negative mood manipulation and a rumination/distraction task differed between high defensive (HD) and low defensive (LD) individuals. At baseline, high defensive participants exhibited significantly greater relative left frontal EEG activity than low defensive participants. HD also exhibited greater relative left anterior activity during both the negative mood induction and during the rumination/distraction task, regardless of group assignment. Contrary to predictions, there were no differences in self-reported mood between HD and LD in either the rumination or distraction group. A significant interaction was found between gender and group, indicating that anterior alpha asymmetry patterns differed for men and women during the rumination/distraction task.

EEG during lavender and rosemary exposure in infants of depressed and non-depressed mothers

This study investigated whether exposure to lavender or rosemary would change electroencephalographic (EEG) activity and behavior in infants of depressed and non-depressed mothers. Twenty newborns were exposed to a 10% (v/v) concentration of rosemary oil or lavender oil. Their EEG and behavior (via a video camera) were simultaneously recorded for 2-min each at baseline and during odor exposure. Group inclusion (depressed versus non-depressed) was based on mothers’ CES-D scores. Although the groups did not differ at baseline and the two odors did not differentially affect the EEG, the infants of depressed mothers showed increased relative left frontal EEG asymmetry from baseline to the odor exposure phase. Infants of non-depressed mothers showed no change in frontal EEG asymmetry from baseline to the odor exposure phase. At least in adults, greater relative left frontal EEG asymmetry has been associated with an approaching pattern of behavior and response to positive stimuli, while greater relative right frontal EEG asymmetry has been associated with a withdrawing pattern of behavior and response to negative stimuli. Among the behaviors recorded; negative affect, head turns, lip licking, and nose wrinkling, the only differences were that the infants of depressed mothers showed increased head turning during the odor exposure. These results suggest that infants of depressed and non-depressed mothers respond differently to odors.

Relative right versus left frontal EEG in neonates.

Although infants have been noted to have greater relative right or left frontal EEG as early as the neonatal period, other ways in which these newborns differ have not been reported. In this study, 48 newborns were divided on the basis of greater relative right versus greater relative left frontal EEG to determine whether these groups differed in other ways at the neonatal period including behavior, physiology, and biochemistry. We also were interested in whether these EEG patterns were related to any prenatal maternal variables including mood states (depression, anxiety, anger) and biochemistry as well as fetal activity. The greater relative right frontal EEG newborns had mothers with lower prenatal and postnatal serotonin and higher postnatal cortisol levels. The mothers of the greater relative right frontal EEG newborns also had greater relative right frontal EEG activation and lower vagal tone. The greater relative right frontal EEG newborns themselves had elevated cortisol levels, showed a greater number of state changes during sleep/wake behavior observations, and performed less optimally on the Brazelton Neonatal Behavior Assessment (T. B. Brazelton, 1973) including the habituation, motor, range of state, excitability, and depressive symptoms scales. These data suggest that greater relative right frontal EEG newborns may be at greater risk for developmental problems than those with greater relative left frontal EEG activation. In addition, a discriminant function analysis correctly classified 67% of the newborns' EEGs by prenatal maternal variables, suggesting that these might be used to target pregnant women for prenatal intervention.

EEG ASYMMETRY RESPONSES TO LAVENDER AND ROSEMARY AROMAS IN ADULTS AND INFANTS

Frontal EEG asymmetry shifting from baseline was examined in adults and infants exposed to lavender and rosemary by reanalyzing previously published data, using techniques different from those utilized in the original two studies. Results from Study 1 on 39 adults revealed significant EEG shifting in the lavender group, with greater relative left frontal EEG activation (associated with greater approach behavior and less depressed affect). The participants in the two aroma groups were further grouped by those with greater baseline, relative to left frontal EEG activation, versus those with a greater baseline, relative to right frontal activation. Collapsing across aroma groups, those with greater baseline, relative to right frontal activation, shifted left during the aroma. Those with greater baseline relative to left frontal activation did not change. In the rosemary group, those with greater baseline relative to right frontal EEG activation shifted left during the aroma, while those with greater baselines relative to left frontal EEG activation shifted right. In the lavender group, those with greater baselines relative to right frontal baseline EEG activation shifted left, but those with greater baselines relative to left baseline did not shift. Study 2 on 27 full-term newborns revealed no significant shifts in asymmetry in either aroma group. However, when the aroma groups were collapsed, the right frontal EEG group exhibited significant shifting relative to left frontal EEG activation. This finding was similar to the adult findings, suggesting that either lavender or rosemary may induce left frontal EEG shifting in adults and infants who show greater baselines relative to right frontal EEG activation.

Frontal brain electrical activity (EEG) distinguishes valence and intensity of musical emotions

Using recent regional brain activation/emotion models as a theoretical framework, we examined whether the pattern of regional EEG activity distinguished emotions induced by musical excerpts which were known to vary in affective valence (i.e., positive vs. negative) and intensity (i.e., intense vs. calm) in a group of undergraduates. We found that the pattern of asymmetrical frontal EEG activity distinguished valence of the musical excerpts. Subjects exhibited greater relative left frontal EEG activity to joy and happy musical excerpts and greater relative right frontal EEG activity to fear and sad musical excerpts. We also found that, although the pattern of frontal EEG asymmetry did not distinguish the intensity of the emotions, the pattern of overall frontal EEG activity did, with the amount of frontal activity decreasing from fear to joy to happy to sad excerpts. These data appear to be the first to distinguish valence and intensity of musical emotions on frontal electrocortical measures.

Frontal brain electrical activity (EEG) distinguishes valence and intensity of musical emotions

Using recent regional brain activation/emotion models as a theoretical framework, we examined whether the pattern of regional EEG activity distinguished emotions induced by musical excerpts which were known to vary in affective valence (i.e., positive vs. negative) and intensity (i.e., intense vs. calm) in a group of undergraduates. We found that the pattern of asymmetrical frontal EEG activity distinguished valence of the musical excerpts. Subjects exhibited greater relative left frontal EEG activity to joy and happy musical excerpts and greater relative right frontal EEG activity to fear and sad musical excerpts. We also found that, although the pattern of frontal EEG asymmetry did not distinguish the intensity of the emotions, the pattern of overall frontal EEG activity did, with the amount of frontal activity decreasing from fear to joy to happy to sad excerpts. These data appear to be the first to distinguish valence and intensity of musical emotions on frontal electrocortical measures.

Frontal Brain Electrical Activity in Shyness and Sociability

A number of studies have shown that shyness and sociability may be two independent personality traits that are distinguishable across a variety of measures and cultures. Utilizing recent frontal activation–emotion models as a theoretical framework, this study examined the pattern of resting frontal electroencephalographic (EEG) activity in undergraduates who self-reported high and low shyness and sociability. Analyses revealed that shyness was associated with greater relative right frontal EEG activity, whereas sociability was associated with greater relative left frontal EEG activity. Also, different combinations of shyness and sociability were distinguishable on the basis of resting frontal EEG power. Although high-shy/high-social and high-shy/low-social subjects both exhibited greater relative right frontal EEG activity, they differed significantly on EEG power in the left, but not right, frontal lead. High-shy/high-social subjects exhibited significantly less EEG power (i.e., more activity) in the left frontal lead compared with the high-shy/low-social subjects. These findings suggest that in distinguishing individual differences in personality and personality subtypes, it is important to consider not only frontal EEG asymmetry measures, but also the pattern of absolute EEG power in each frontal hemisphere.

Infants of intrusive and withdrawn mothers

Two styles of mother-infant interactions have been observed in depressed mothers, including an intrusive style (overstimulating behavior) and a withdrawn style (understimulating behavior). To examine how these styles affect infants, we assessed 87 infants and their mothers, who had been assigned to “intrusive” or “withdrawn” profiles, based on their face-to-face interactive behaviors with their 3-month-old infants. Behavioral assessments were made at 3, 6, and 12 months. The results indicated that infants of withdrawn mothers showed less optimal interactive behavior, greater relative right frontal EEG asymmetry (due to decreased left frontal EEG activation and increased right frontal EEG activation), and lower Bayley Mental Scale scores at 1 year. Infants of intrusive mothers had higher catecholamine and dopamine levels, and their EEG patterns showed greater relative left frontal EEG asymmetry (due to increased left frontal EEG activation and decreased right frontal EEG activation).

The role of frontal activation in the regulation and dysregulation of social behavior during the preschool years

AbstractWe examined whether the interaction of resting frontal electroencephalogram (EEG) asymmetry and social behavior during peer play was related to the occurrence of maladaptive behavior in preschoolers. Two independent cohorts of children were observed interacting in same-age and -gender play quartets at 4 years of age. Each child was also seen individually for a psychophysiology session during which time measures of EEG activity were recorded. We found that highly sociable children who exhibited greater relative right frontal EEG asymmetry were more likely to exhibit externalizing problems than sociable children who exhibited greater relative left frontal EEG asymmetry. We also found that shy children who exhibited greater relative right frontal EEG asymmetry were more likely to exhibit internalizing problems than shy children who exhibited left frontal EEG asymmetry. These findings suggest that the pattern of frontal EEG asymmetry in combination with social behavioral style is a significant predictor of maladaptive behavior problems during the preschool period.