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As depression has been a major contributor to the global disease burden, objective and effective computer-aided diagnosis has become an urgent problem. This study aims to assess the frontal asymmetry variation of alpha electroencephalography (EEG) in different severity depression patients and to find promising biomarkers for future depression recognition. Three-channel EEG signals from 69 depression patients (divided into three groups according to illness severity) and 14 healthy subjects were collected. Except for cross-sample entropy (CSEn), two new asymmetry indexes (Asy_SEn and Asy_LZC) based on complexity measures were proposed to quantify the difference among the four groups. One-way ANOVA was used to test the difference among all four groups, followed by the group t-test to test the difference between each two groups. All indexes show significantly increased frontal alpha asymmetry in depressive groups compared with the healthy group, and the asymmetry keeps increasing as the depression deepens. The Asy_LZC value of the confirmed depression group (0.0015 ± 0.0008) is substantially higher than the other three groups (−0.0010 ± 0.0008, −0.0006 ± 0.0008, and −0.0007 ± 0.0006). And the Asy_SEn value of the healthy group (−0.0023 ± 0.0007) is significantly lower than the two depressive groups (0.0001 ± 0.0005 and 0.0007 ± 0.0007). All healthy CSEn between each two channels is considerably lower than depressive groups with p

Emotions play an important role in human interaction and decision-making processes. Frontal asymmetry in brain activity is a promising neurophysiological indicator of emotion. Emotions are psychologically explained by the valence-arousal model, but as yet, frontal asymmetry has not been fully explained by this model. In this study, we explored frontal asymmetry of emotions based on the valence-arousal model using the same auditory stimulus. Changes in emotional states using self-report questionnaires were investigated before and after the auditory stimulus. Spectral power and weighted phase lag index were calculated in the delta, theta, alpha, beta, and gamma bands. Phase-amplitude coupling was also measured to explore communication among different frequency bands associated with emotions. After the auditory stimulus, alpha power decreased in both left and right frontal regions and the delta-weighted phase lag index in the left-right regions was increased. However, no frontal asymmetry was identified after the auditory stimulus. Additionally, we explored the brain changes according to the valence-arousal model based on emotional states. After the auditory stimulus, frontal asymmetry of alpha power was clearly observed only for negative valence. This finding was possible because subjective emotions were considered despite listening to the same stimulus. Finally, phase-amplitude coupling identified left-hemisphere dominance after the auditory stimulus, regardless of subjective emotions. These results may help us understand frontal asymmetry associated with emotional mechanisms. In addition, these findings can be used directly in the brain-computer interface to improve emotion recognition performance for real-world practical applications.

Electroencephalogram (EEG) asymmetry has been widely studied across the lifespan, with multiple studies conducted in infancy. However, few have investigated frontal EEG asymmetry in the context of emotional-eliciting tasks, controlling for baseline to focus on an experimental episode response. The present study was designed to address this gap in research, predicting frontal EEG asymmetry response in the context of the Still Face procedure (SFP), examining mother–infant interaction quality and infant temperament attributes as potential contributors. Moderation by infant temperament was also considered. Results indicated that intensity and tone of parent–child interactions as well as Surgency/Positive Affectivity (and component scales of Approach and Activity Level) predicted frontal EEG asymmetry during SFP, controlling for baseline. Importantly, moderation was noted for Surgency/Positive Affectivity and its Approach component, reflected in significant interaction terms and follow-up simple slope tests. That is, the effect of intensity in mother–infant interactions was qualified by child overall surgency, and approach more specifically – infants demonstrating higher levels of Surgency/Positive Affectivity and Approach in particular were protected from the right frontal EEG response to SFP noted in the context of intense concurrent exchanges with mothers.

Relatively little work has examined potential interactions between child intrinsic factors and extrinsic environmental factors in the development of negative affect in early life. This work is important because high levels of early negative affectivity have been associated with difficulties in later childhood adjustment. We examined associations between infant frontal electroencephalogram (EEG), maternal parenting behaviors, and children’s negative affect across the first two years of life. Infant baseline frontal EEG asymmetry was measured at 5 months; maternal sensitivity and intrusiveness were observed during mother-child interaction at 5 and 24 months; and mothers provided reports of toddler negative affect at 24 months. Results indicated that maternal sensitive behaviors at 5 months were associated with less negative affect at 24 months, but only for infants with left frontal EEG asymmetry. Similarly, maternal sensitive behaviors at 24 months were associated with less toddler negative affect at 24 months, but only for infants with left frontal EEG asymmetry. In contrast, maternal intrusive behaviors at 5- and 24-months were associated with greater toddler negative affect, but only for infants with right frontal EEG asymmetry at 5-months. Findings suggest that levels of negative affect in toddlers may be at least partially a result of interactions between children’s own early neurophysiological functioning and maternal behavior during everyday interactions with children in the first two years of life.

Time-shared performance asymmetry in right-handed subjects is attributed to left hemisphere lateralization of both speech and motor control of the contralateral right hand. The present study investigated patterns of time-shared motor performance and EEG asymmetry in mentally retarded individuals. Thirty-six institutionalized mentally retarded individuals served as subjects. All subjects had previously come to the laboratory for an EEG recording and were known to be cooperative. Analysis of variance of tapping scores showed that there were no significant differences between left- and right-handed subjects; hence, the data for all subjects are pooled in the analyses that follow. In conclusion, the assessment of baseline hemispheric EEG patterns is seen to correlate significantly with interference during time-shared motor performance in a sample of institutionalized mentally retarded individuals. It is possible that such assessments may prove helpful in prescribing sensorimotor remediation. .

It is widely accepted that physical exercises (PEs) not only are good for fitness but also contribute to mental health and well-being. The positive influence of PEs on emotion has become a topic of much excitement. However, a quantitative study is required to discuss the effect of short-term moderate-intensity PE on the emotional response by using electroencephalogram (EEG) asymmetry. The experiments, including 20-min moderate-intensity cycling and EEG data acquisition with picture-induced emotion assessment protocol, were designed in this paper. The experiment procedure consists of two emotion assessment sessions, each of which contains 24 pictures. About 80 participants were randomly allocated into the exercise group and the control group. Participants in the exercise group were instructed to have a 20-min moderate-intensity cycling after the first assessment session, then rested until their heart rates recovered to baselines and their emotional states were assessed again in the second session. The control group only had a 20-min break without the cycling exercise between the two sessions. It was observed that, in the control group, the EEG asymmetry had no significant difference in these two assessment sessions for both positive and negative stimulations. However, in the exercise group, the difference of the EEG asymmetry before and after PE was significant only in response to negative stimulations. Further, the in-depth analysis of EEG asymmetry index changes of individual participants shows that the short-term moderate-intensity PE has a positive impact in response to negative stimulations. The proposed experiments show that the negative emotional experience can be reduced by the moderate-intensity PE and support the hypothesis that the moderate-intensity PE is good at improving emotional response to negative stimulations. This study provides the evidence of positive effects of PE in the domain of emotion regulation with experimental data.

Resting frontal EEG alpha asymmetry has been extensively examined as a marker of motivational disposition. Recent research has examined how this trait-level marker of motivation influences an individual’s internal error monitoring (indexed by the error-related negativity; ERN), with mixed findings as to whether more negative ERNs are associated with greater left or right alpha power. Data from 339 children who completed an incentivized Go/No-Go task annually from Kindergarten through 2nd grade were examined for an association between ERN amplitude and EEG asymmetry, and for whether the association was developmentally stable. Results indicate an association between left-dominant activation and a more negative amplitude in Kindergarten, with an inversion of this association emerging by 2nd grade, such that a more negative ERNs were associated with right-dominant activation. We suggest that the association between EEG asymmetry and ERN amplitude is likely modulated by task condition (e.g., incentivization) and experience over time (e.g., habituation).

Introduction: Increase in right relative to left frontal electroencephalography (EEG) activity has been observed in patients with schizophrenia, both in cognitive tasks and during rest; and this la...

Heightened sensitivity to losses, known as loss aversion, is a putative avoidance behaviour, which commonly influences decision-making, particularly in economic scenarios where participants have a 50/50 chance of winning or losing money. Evidence from neuropsychology, EEG and TMS research suggests individual differences in loss aversion may be explained by neural differences in the lateralisation of the right hemisphere. 40 healthy participants underwent an EEG recording during resting state and subsequently performed a behavioural loss aversion task, in which they had an equal chance of winning or losing money. EEG asymmetry in the alpha band at central and posterior sites was associated with individual differences in behavioural loss aversion. This asymmetry was driven by a combination of increased activation in the right hemisphere and decreased activation in the left hemisphere and the site of this asymmetry differed for females and males. These findings are discussed in relation to behavioural avoidance.

Objective Young 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 1 year (Time 1), behavior at 2 years (Time 2) and their longitudinal associations within a sample of infants with VI. Frontal asymmetry in the VI sample at 1 year was also compared cross-sectionally to an age-matched typically sighted (TS) group. Methods At 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. Results 63.6% 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). Conclusions Left frontal asymmetry correlates with later behavior risk within this vulnerable population. Significance These findings make an important first contribution regarding the utility of frontal EEG asymmetry as a method to investigate risk in infants with VI.

Asymmetry in cortical activity was tested for short- and long-term stability during the first year of life. Infants (N = 129) completed a total of four laboratory visits: two visits occurred about 1 week apart when infants were 6 months old, and two visits occurred about 1 week apart when infants were 12 months of age. At each laboratory visit, EEG readings were taken during five 1-min, neutral baselines as well as during a negative and a positive emotion-eliciting task. The stability of hemispheric asymmetry was assessed at midfrontal (F3/4, F7/8) and parietal (P3/4) electrode sites. Asymmetry in baseline and fear-eliciting episodes showed moderate short-term stability. Long-term stability was apparent when assessments were composited at 6 months and 12 months. Frontal asymmetry was greater than parietal asymmetry for baseline recordings. There was minimal evidence for stability in asymmetry during positive emotion tasks. Results are discussed with regard to the collection and interpretation of alpha asymmetry measures during infancy.

Asymmetric patterns of frontal brain electrical activity reflect approach and avoidance tendencies, with stability of relative right activation associated with withdrawal emotions/motivation and left hemisphere activation linked with approach and positive affect. However, considerable shifts in approach/avoidance-related lateralization have been reported for children not targeted because of extreme temperament. In this study, dynamic effects of frontal electroencephalogram (EEG) power within and across hemispheres were examined throughout early childhood. Specifically, EEG indicators at 5, 10, 24, 36, 48, and 72 months-of-age (n = 410) were analyzed via a hybrid of difference score and panel design models, with baseline measures and subsequent time-to-time differences modeled as potentially influencing all subsequent amounts of time-to-time change (i.e., predictively saturated). Infant sex was considered as a moderator of dynamic developmental effects, with temperament attributes measured at 5 months examined as predictors of EEG hemisphere development. Overall, change in left and right frontal EEG power predicted declining subsequent change in the same hemisphere, with effects on the opposing neurobehavioral system enhancing later growth. Infant sex moderated the pattern of within and across-hemisphere effects, wherein for girls more prominent left hemisphere influences on the right hemisphere EEG changes were noted and right hemisphere effects were more salient for boys. Largely similar patterns of temperament prediction were observed for the left and the right EEG power changes, with limited sex differences in links between temperament and growth parameters. Results were interpreted in the context of comparable analyses using parietal power values, which provided evidence for unique frontal effects.

Objective: Asymmetry is a subtle but pervasive aspect of the human brain, and it may be altered in several psychiatric conditions. MRI studies have shown subtle differences of brain anatomy between people with major depressive disorder and healthy control subjects, but few studies have specifically examined brain anatomical asymmetry in relation to this disorder, and results from those studies have remained inconclusive. At the functional level, some electroencephalography studies have indicated left fronto-cortical hypoactivity and right parietal hypoactivity in depressive disorders, so aspects of lateralized anatomy may also be affected. The authors used pooled individual-level data from data sets collected around the world to investigate differences in laterality in measures of cortical thickness, cortical surface area, and subcortical volume between individuals with major depression and healthy control subjects.Methods: The authors investigated differences in the laterality of thickness and surface area measures of 34 cerebral cortical regions in 2,256 individuals with major depression and 3,504 control subjects from 31 separate data sets, and they investigated volume asymmetries of eight subcortical structures in 2,540 individuals with major depression and 4,230 control subjects from 32 data sets. T-1-weighted MRI data were processedwith a single protocol using FreeSurfer and the Desikan-Killiany atlas. The large sample size provided 80% power to detect effects of the order of Cohen's d=0.1.Results: The largest effect size (Cohen's d) of major depression diagnosis was 0.085 for the thickness asymmetry of the superior temporal cortex, which was not significant after adjustment for multiple testing. Asymmetry measures were not significantly associated with medication use, acute compared with remitted status, first episode compared with recurrent status, or age at onset.Conclusions: Altered brain macro-anatomical asymmetry may be of little relevance to major depression etiology in most cases.

Asymmetry in frontal alpha activation (FAA) has been associated with specific behavior patterns. Greater activation in the left frontal cortex is related to "approach" motivation, while greater activation in the right cortex is associated with "withdrawal" motivation. Moreover, resting FAA is stable over time among adults. This stability has not been demonstrated among adolescents, and the correspondence between resting FAA and personality has been inconsistently observed. The present study examined stability of FAA and the association between resting FAA and behavioral activation among adolescents. At baseline and 4 months, 99 adolescents completed a resting electroencephalogram (EEG) and a pencil-and-paper measure of personality (BIS/BAS). FAA showed good stability over time (Intra-class correlation coefficient=0.65, p

Mindfulness is defined as nonjudgmental attention to experiences in the present moment. Frontal EEG asymmetry can be considered as a biological indicator of affective style. Up to date, most studies examined how mindfulness training influenced frontal EEG asymmetry at resting baseline; however, few studies investigated how mindfulness training influenced frontal EEG asymmetry during emotional challenge. The present study examined simultaneously how mindfulness training influenced frontal EEG asymmetries at resting baseline and during emotional challenge in non-clinical population. In order to test the effect of mindfulness training, the present study tested the mindfulness-based cognitive therapy (MBCT) group (n = 16) and the waitlist control (WC) group (n = 20) at baseline, 4 weeks, and 8 weeks. A testing phase (baseline, 4 weeks, and 8 weeks) × time point (the first sad film phase, relaxation phase, the second sad film phase, and the meditation intervention phase) × group (MBCT and WC), ANOVA was conducted for the tasking EEG data. The results showed that there was significant testing phase × group interactive effect for frontal EEG asymmetry during emotional challenge. Further analysis showed that frontal EEG asymmetry scores at 8 weeks were lower than at baseline and 4 weeks for the MBCT group but not significant differences for the WC group. However, mindfulness training did not influence frontal EEG asymmetry at resting baseline. Therefore, it is concluded that 8 weeks of mindfulness training can enhance left frontal EEG asymmetry during emotional challenge. These results indicated that frontal EEG asymmetry during emotional challenge may be an index of affective style.

Cerebral hemispheres, although similar, are neither completely symmetrical in structure nor equivalent in function. EEG asymmetry studies have been directed more to frequency than to amplitude analysis. Objective Better definition of normal amplitude asymmetry values on the classical EEG frequency bands. Results EEG amplitude asymmetry index (AAI) is physiologically low in normal adults, differences usually lesser than 7%. Conclusion Persistent or intermittent amplitude asymmetry regional differences higher than 7% may be suggestive of pathology after adequate correlation with clinical data and EEG classical visual analysis. RESUMO Os hemisférios cerebrais não são simétricos em morfologia ou funções. Tradicionalmente, os estudos de assimetria do EEG focaram mais na análise de frequências do que na de amplitudes. Objetivo Contribuir para melhor definição dos valores normais de assimetria de amplitudes nas faixas de frequência clássicas do EEG. Resultados O índice de assimetria de amplitudes é fisiologicamente baixo em adultos, usualmente menor do que 7%. Conclusão Se adequadamente correlacionadas aos dados clínicos e à análise visual do EEG, assimetrias persistentes ou intermitentes de amplitude acima de 7% podem ser sugestivas de patologia.

The present study examined the differences in frontal EEG asymmetry during emotion regulation between participants who had different levels of trait mindfulness. EEG recordings were taken from 23 high mindfulness adolescents (Mage = 12.34) and 22 low mindfulness adolescents (Mage = 12.53) during the Reactivity and Regulation-Image Task. The results showed that (1) high mindfulness adolescents had greater left (relative to right) asymmetry than low mindfulness adolescents in down-regulation and up-regulation conditions; however, there was no significant difference in the non-regulation condition; (2) In the up-regulating condition, adolescents showed greater right (relative to left) asymmetry for negative stimuli compared to neutral stimuli; however, there was no significant difference in down-regulation and non-regulation conditions. The results provide neurological evidence that trait mindfulness was highly related to the regulation of emotions and affects how emotions are processed.

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 = 6.39 years, S.D. = 0.15 years), 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 2 years (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.

Major depression is characterized by abnormal reward processing and reinforcement learning (RL). This impairment might stem from deficient motivation processes, in addition to reduced reward sensitivity. In this study, we recorded 64-channel EEG in a large cohort of major depressive disorder (MDD) patients and matched healthy controls (HC) while they performed a standard RL task. Participants were asked to discover, by trial and error, several hidden stimulus-response associations having different reward probabilities, as enforced using evaluative feedback. We extracted induced fronto-midline Theta (FMT) power time-locked to the response and feedback as neurophysiological index of RL. Furthermore, we assessed approach-related motivation by measuring frontal alpha asymmetry concurrently. At the behavioral level, MDD patients and HCs showed comparable RL. At the EEG level, FMT power systematically varied as a function of reward probability, with opposing effects found at the response and feedback levels. Although this global pattern was spared in MDD, at the feedback level these patients showed however a steep FMT power decrease across trials when reward probability was low. Moreover, they showed impaired approach-related motivation during task execution, as reflected by frontal Alpha asymmetry. These results suggest a dissociation between (globally spared) RL and (impaired) approach motivation in MDD.

Introduction: Electroencephalographically-measured frontal alpha asymmetry is shown to reflect changes in mood. Negative mood changes are purported to limit exercise capacity in some groups, thereby contributing to the current epidemic of overweight, obesity and related diseases. Aim: This study tests the hypothesis that the mood changes associated with aerobic exercise are correlated with changes in frontal EEG asymmetry. Materials and Methods: Healthy young adult African-American (AA) men (n=8) and women (n=8) were subjected to quantitative EEG brain mapping of delta, theta, alpha and beta bandwidths after a period of rest or a period of aerobic exercise at a fixed energy expenditure. Brain mapping was performed within 30 min after rest or exercise, immediately before completing a questionnaire which included a total mood disturbance score (tMDS) and specific mood subcategory scores consisting of vigor, fatigue, anger, confusion tension, depression. Prefrontal and inferior frontal asymmetry were evaluated. Significance of differences between rest and exercise prefrontal and inferior frontal asymmetry was evaluated by one-way ANOVA. Results: Exercise-related decrements in asymmetry were significant for prefrontal delta (p≤0.05) and marginally significant for prefrontal alpha and theta (p=0.07) in the male subjects. There were significant decrements in tension and tMDS for the males and females and a decrement in depression score for the females between the post-control rest and the post-exercise conditions. Significant negative correlation between the tMDS and prefrontal beta asymmetry was found, across post-rest and post-exercise (r= -0.38, p≤0.05, 30 df). There were also significant correlations between confusion and prefrontal beta asymmetry during rest (r= 0.48, p≤0.05, 14 df), between vigor and inferior frontal beta asymmetry, between vigor and both inferior frontal theta asymmetry and inferior frontal delta asymmetry during exercise (r= 0.46, -0.54, p≤0.05, 14 df), and between vigor, confusion, tension and inferior frontal delta asymmetry post-exercise (r= -0.49, -0.45, -0.49, p≤0.05, 14 df). Conclusion: The high prefrontal beta asymmetry associated with depressed mood in AA males and females, the lessening of prefrontal delta, theta and alpha asymmetry in the males and the lower depression scores after aerobic exercise in the females seem to support the hypothesis that decreased asymmetry with increased activation of the right prefrontal and frontal cortices may accompany the mood changes associated with aerobic exercise.

Previous studies have documented the serotonin transporter linked polymorphic region (5-HTTLPR) as a genetic susceptibility variant that contributes to variability in outcomes related to affective psychopathology, with the short allele associated with negative affectivity and the long allele associated with positive affectivity. In a separate but related line of research, extensive evidence suggests that frontal electroencephalography (EEG) hemispheric asymmetry in the alpha band is also associated with risk for affective psychopathologies, with leftward asymmetry associated with approach-related behavior patterns and rightward frontal EEG asymmetry associated with withdrawn behavioral tendencies. We examined frontal EEG hemispheric asymmetries in relation to 5-HTTLPR genotyping in 70 children between 4 and 6 years of age. Analyses revealed that frontal EEG lateralization interacted with genotype such that children homozygous for the short allele exhibited rightward frontal EEG asymmetries, children who were homozygous for the long allele consistently exhibited a positive pattern of leftward asymmetry, and heterozygotes exhibited equivalent left and right frontal activity. These findings suggest that the 5-HTTLPR short allele may provide a degree of susceptibility for later affective psychopathology in adolescence and adulthood, through mediation of frontal brain activity that is associated with cognitive–behavioral withdrawal tendencies and negative affectivity.

Background Frontal EEG asymmetry is a widely studied correlate of emotion processing and psychopathology. Recent research suggests that frontal EEG asymmetry during resting state is related to approach/withdrawal motivation and is also found in affective disorders such as major depressive disorder. Patients with borderline personality disorder (BPD) show aberrant behavior in relation to both approach and withdrawal motivation, which may arguably be associated with their difficulties in emotion processing. The occurrence and significance of frontal EEG asymmetry in BPD, however, has received little attention. Results Thirty-seven BPD patients and 39 controls underwent resting EEG and completed several psychometric questionnaires. While there were no between-group differences in frontal EEG asymmetry, in BPD frontal EEG asymmetry scores correlated significantly with alexithymia. That is, higher alexithymia scores were associated with relatively lower right-frontal activity. A subsequent analysis corroborated the significant interaction between frontal EEG asymmetry and alexithymia, which was moderated by group. Conclusions Our findings reveal that lower right frontal EEG asymmetry is associated with alexithymia in patients with BPD. This finding is in accordance with neurophysiological models of alexithymia that implicate a right hemisphere impairment in emotion processing, and could suggest frontal EEG asymmetry as a potential biomarker of relevant psychopathology in these patients.

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.

More right-sided frontal brain resting activity has been postulated to be a correlate of major depression in adults. In children and adolescents, more right-sided activity (as indicated by more left-sided alpha activity) seems to be associated with psychosocial risk factors. However, an association of frontal asymmetry and manifest unipolar depression has not been shown in adolescents so far. We analyzed frontal asymmetry in 20 adolescents (12-17 years) with unipolar depression (12 with first episode, 8 with recurrent depression) and 31 healthy age-matched controls. We found significantly less left-sided alpha power over frontal Regions of Interest in patients, while controls exhibited no asymmetry. In the control group, more left-sided frontal alpha correlated with higher depression scores, which was not observed in the patient group. Our results suggest developmental effects on frontal asymmetry, and prompt further investigations in adolescents to clarify the role of frontal asymmetry in adolescent major depression.

a b s t r a c t Two hundred and thirty-three 5-month-old infants and their mothers participated in a study designed to examine the influence of maternal sensitivity and infant neurophysiology, as well as interactions between these, on infants' regulatory behavior and reactivity to emotional challenge. Maternal sensitivity was measured during two mother-child free- play episodes prior to the challenge task. Infant neurophysiology was derived from a measure of resting EEG asymmetry collected during a baseline episode. Infant regula- tory behaviors (mother orienting and distraction) and reactivity to challenge (negative affect) were assessed during an arm restraint procedure. Maternal sensitivity predicted mother-orienting behavior for all infants, regardless of baseline EEG asymmetry. Mater- nal sensitivity also predicted more distraction behaviors for infants with left frontal EEG asymmetry at baseline. In contrast, maternal sensitivity predicted more negative affect for infants with right frontal EEG asymmetry at baseline. These findings lend support for the hypothesis that maternal sensitivity and infant neurophysiological functioning interact to predict regulatory behavior and reactivity and are discussed in terms of the significance for understanding infant regulatory development in the first year of life.

Mid-frontal and mid-lateral (F3/F4 and F7/F8) EEG asymmetry has been associated with motivation and affect. We examined alpha EEG asymmetry in depressed and healthy participants before and after Behavioral Activation treatment for depression; examined the association between alpha EEG asymmetry and motivational systems and affect; and evaluated the utility of alpha EEG asymmetry in predicting remission.Depressed (n=37) and healthy participants (n=35) were assessed before and after treatment using a clinical interview, a task to measure baseline EEG, and questionnaires of behavioral activation and inhibition, avoidance, and affect.Alpha EEG asymmetry was significantly higher in depressed than healthy participants at pre-treatment, positively correlated with negative affect and behavioral inhibition, and inversely correlated with lower behavioral activation sensitivity.Heightened alpha EEG asymmetry in depressed participants was significantly associated with increased behavioral inhibition and negative emotion and was independent of clinical remission.

Evidence suggests that asymmetry in frontal electrical activity predicts responses to aversive experiences, such that higher left-sided activity might dampen responses to trauma reminders. We measured frontal asymmetry at rest and during viewing of a trauma film, and assessed startle responses to film-reminder images. To explore potential moderators, we compared two films (Study 1; N = 64) and modulated reappraisal (Study 2; N = 72). As expected, left frontal activation during film viewing predicted dampened responses in individuals who viewed a staged road accident. However, this effect tended to be reversed when a genocide documentary was used. In Study 2, all participants viewed the genocide film. Left frontal activity at rest again predicted higher startle responses, while reappraisal did not moderate the effects. Thus, the type of trauma film plays a crucial role in the effects of frontal asymmetry, which warrants further critical investigation. Descriptors: Eye-blink startle, Frontal alpha asymmetry, Trauma film, Aversive memories, Post-traumatic stress disorder

Background: This purpose of this study was to determine the relationship between resting frontal electroencephalogram (EEG) brain activity and the interaction with the horse in young children with autism spectrum disorder (ASD).Methods: Resting frontal EEG alpha asymmetry was recorded from two young children with ASD and two young typical children matched for age and gender during a baseline and an interaction conditions with the horse.Results: Young children with ASD exhibited higher left frontal dominance during the baseline condition. While grooming the horse, young children with ASD exhibited the right frontal dominance.Conclusions: This change may be attributed to the interaction with the horse. It changed the attentional focus of young children with ASD. In addition, the calmness of the horse might be transformed to young children with ASD. Future studies with larger sample sizes and behavioural measures of social functioning may help explain the horse related benefits in children with ASD.

The present study explores both resting cortical EEG asymmetry and vagally-mediated heart rate variability (HRV), as an index for vagal tone, as physiological correlates of self-reported attentional control in a sample of 53 healthy young adults. Regression analyses indicate that higher vagally-mediated HRV and lower right-sided parietal activity in the β 2 frequency range (20–30 Hz) are significant predictors of larger attentional control. Results are in line with some of the basic features of the neurovisceral integration model and stress the role of parietal areas in attentional control capabilities, thus aiming to consider attentional control as a trait-like disposition.

Associations between brain oscillations and depressive disorders have been studied for many years, leading to the development of prominent theories (e.g., the frontal EEG asymmetry). The brain, however, is a complex nonlinear system, and tools from the Nonlinear Dynamic Systems (NDS) theory are increasingly used to better understand its complex rhythms. This scientific review aimed at gathering relevant evidence on the use of nonlinear measures (those derived from the NDS) to identify biomarkers hidden under the brain oscillations of depressive patients. Thus, electroencephalographic (EEG) and magnetoencephalographic (MEG) studies which aimed either to compare depressives and healthy controls’ oscillations (diagnostic studies) or to examine the efficacy of interventions to ameliorate depressive symptomatology (intervention studies) on those oscillations were selected. As a result, 12 diagnostic studies and nine intervention studies were reviewed. Diagnostic studies essentially examined the brain oscillations in the broad frequency band and reported larger complexity or irregularity in depressives, as shown by the fractal dimension measures and informational measures.

Frontal EEG asymmetry has been recognized as a useful method in determining emotional states and psychophysiological conditions. For the current research, resting prefrontal EEG was measured before, during and after listening to sad music video. Data were recorded and analyzed using a wireless EEG module with digital results sent via Bluetooth to a remote computer for further analysis. The relative alpha power was utilized to determine EEG asymmetry indexes. The results indicated that even if a person had a stronger right hemisphere in the initial phase a significant shift first occurred during audio-video stimulation and was followed by a further inclination to left EEG asymmetry as measured after the stimulation. Furthermore the current research was able to use prefrontal EEG to produce results that were mostly measured at the frontal lobe. It was also able to provide significant changes in results using audio and video stimulation as to previous experiments that made use of audio stimulation. In the future, more experiments can be conducted to obtain a better understanding of a person’s appreciation or dislike toward a certain video, commercial or other multimedia contents through the aid of convenient EEG module.

The rate and timing of spontaneous eye blinking (SB) may be used to explore mechanisms of cognitive activity in infancy. In particular, SB rate is believed to reflect some dimensions of dopamine function; therefore, we hypothesized that SB rate would relate to working memory performance and to frontal electroencephalogram (EEG) asymmetry. Forty, 10-mo-old infants completed an A-not-B task while SB and EEG were measured throughout. We found that SB rate varied across phases of the task, variability in SB rate was positively related to working memory performance, and frontal EEG asymmetry was related to individual differences in the rate of SB. Results provide indirect, but convergent support for the hypothesis that SB rate reflects dopamine function early in human development. As such, these results have implications for understanding the tonic and phasic effects of dopamine on cognitive activity early in human development.

The main objective of this research was to investigate the association between electroencephalogram (EEG) and semantic memory recall in human participant. A sample of 20 healthy participants was recruited and exposed to 10 minutes animated learning contents. After 30 minutes of the learning session, they performed a memory recall task; the correct and incorrect responses in recall task were recorded for computing the memory performance. EEG amplitude asymmetry was computed for six frequency band (delta, theta, alpha, beta, high beta, and gamma) and the correlation was checked with the memory recall. It was found that the EEG delta asymmetry correlated negatively (r=0.44−0.68; p-value

Several behavioral and physiological adaptations have been developed in evolution of Pinnipeds allowing them to sleep both on land and in water. To date sleep has been examined in detail in eared and true seals (the families of Otariidae and Phocidae). The aim of this study was to examine sleep in another semiaquatic mammal – the walrus, which is the only extant representative of the family Odobenidae. Slow wave and paradoxical sleep (SWS and PS) in the examined walrus (2 year old female, weight 130 kg) averaged 19.4 ± 2.0 and 6.9 ± 1.1% of 24-h when on land, and 20.5 ± 0.8% of 24-h and 1.1 ± 0.6% when in water, respectively. The average duration of PS episode was 6.4 ± 0.6 min (maximum 23 min) when on land and 1.8 ± 0.1 min (maximum 3.3 min) when in water. In water, sleep occurred predominantly while the walrus submerged and lay on the bottom of the pool (89% of total sleep time). The walrus usually woke up while emerging to the surface for breathing. Most often EEG slow waves developed synchronously in both cortical hemispheres (90% of SWS time when on land and 97% when in water). Short episodes of interhemispheric EEG asymmetry usually coincided with brief opening of one eye. The pattern of sleep in the walrus was similar to the pattern of sleep in the Otariidae seals while on land (predominantly bilateral SWS, accompanied by regular breathing) and to the pattern of sleep in the Phocidae while in water (sleep during apneas both in depth and at the surface, interrupted by brief arousal when emerging for breathing).

The effect of color hue saturation on the emotional state (ES) of humans has been investigated. Frontal EEG asymmetry was used to determine the subject’s ES. The emotionogenic stimuli caused converse dynamics of frontal EEG asymmetry. Negative stimuli elicited a decrease in the value of frontal EEG asymmetry, and positive stimuli increased the value of frontal EEG asymmetry in the anterofrontal and posterofrontal leads. These dynamics of frontal EEG asymmetry indicates the formation of an ES corresponding to the presented stimuli. Blue and red color balance modification of stimuli leads to changes in the dynamics of frontal EEG asymmetry during the scanning of emotionally positive and negative stimuli. None of the subjects noticed the color modification of the video stimuli used. This leads us to the conclusion that the change in the frontal asymmetry in response to modified stimuli resulted from an unconscious perception of the modification of the color characteristics of the stimuli. The results show the possibility of the effect of unconscious perception of color characteristics of video stimuli on the ES of humans.

The present research intended first to confirm psychophysiological and cortical responses to valence- and arousal-manipulated stimuli and second to show how the BIS and BAS (Behavioural Inhibition and Activation System) personality characteristics correlated with these psychophysiological and cortical responses. Multiple measures were recorded, such as psychophysiological (skin conductance response, heart rate, and electromyography) and ERPs (event-related potentials) responses, during viewing IAPS figures, that varied in terms of pleasantness (appetitive vs. aversive) and arousing power (high vs. low intensity). Autonomic variables and two ERP positive deflections (P3 and LPP ERP effects) were found to be modulated by valence and arousal rating, with an increased response for high arousing and negative or positive stimuli in comparison with low arousing and neutral stimuli. Moreover, high BAS subjects were more responsive to positive than negative emotions, whereas high BIS subjects responded in greater measure to negative and arousing emotions. Findings were discussed in light of biphasic model of emotion comprehension.

Although previous studies have shown that socially anxious individuals exhibit greater relative right frontal electroencephalogram (EEG) activity at rest, no studies have investigated whether improvements in symptoms as a result of treatment are associated with concomitant changes in resting brain activity. Regional EEG activity was measured at rest in 23 patients with social anxiety disorder (SAD) before and after cognitive behavioral therapy (CBT). Results indicated that patients shifted significantly from greater relative right to greater relative left resting frontal brain activity from pre- to posttreatment. Greater left frontal EEG activity at pretreatment predicted greater reduction in social anxiety from pre- to posttreatment and lower posttreatment social anxiety after accounting for pretreatment symptoms. These relations were specific to the frontal alpha EEG asymmetry metric. These preliminary findings suggest that resting frontal EEG asymmetry may be a predictor of symptom change and endstate functioning in SAD patients who undergo efficacious psychological treatment.

We conducted a pilot study to examine the relations among the patterns of resting regional electroencephalogram (EEG) alpha activity, trait shyness and sociability, and positive and negative symptoms scores in 20 adults with schizophrenia, attending a community-based treatment and rehabilitation center. As predicted, patients' positive symptoms were related to greater relative resting left frontal EEG activity, replicating earlier work. When only adults with low to no positive symptoms were considered, trait shyness was related to greater relative resting right frontal EEG activity, whereas trait sociability was related to greater relative resting left frontal EEG activity. This finding is similar to what is consistently noted in healthy adults. These pilot data suggest that positive symptoms in patients with schizophrenia may obscure the relations between personality and frontal EEG asymmetry measures observed in healthy adults.

Fur seals (pinnipeds of the family Otariidae) display two fundamentally different patterns of sleep: bilaterally symmetrical slow-wave sleep (BSWS) as seen in terrestrial mammals and slow-wave sleep (SWS) with a striking interhemispheric EEG asymmetry (asymmetrical SWS or ASWS) as observed in cetaceans. We examined the effect of preventing fur seals from sleeping in BSWS on their pattern of sleep. Four northern fur seals (Callorhinus ursinus) kept on land were sleep deprived (SD) of BSWS for 3 consecutive days, followed by 1 recovery day. EEG asymmetry was evaluated both visually and by EEG spectral analysis. SD significantly reduced the percentage of high-voltage BSWS (on average to 14% of baseline) and REM sleep (to 60% of baseline) whereas the percentage of low-voltage BSWS was not affected. During the SD period, all seals repeatedly tried to enter BSWS (109–411 attempts per day). SD significantly increased the amount of ASWS in each seal when scored visually (to 116–235% of baseline) and the difference in the EEG slow-wave activity (spectral power in the range of 1.2–4.0 Hz) between the two hemispheres (117–197%) as measured by the asymmetry index. High-voltage BSWS and the amount of SWS in each hemisphere were significantly elevated during the first 4 h of recovery. These data indicate that fur seals display a homeostatic response to the loss of SWS and that alternating SWS in the two hemispheres does not adequately compensate for the absence of BSWS.

Although the pattern of resting frontal brain electrical activity (EEG) has been suggested as a “trait-like” correlate of individual differences in affective style in adults and children, there appear to be no studies that have examined the short-term stability of resting frontal EEG asymmetry measures in typically developing infants. A new approach was examined to study the short-term stability of resting frontal EEG asymmetry measures. Second-by-second frontal EEG asymmetry scores (right power minus left power) were computed across a 90 s baseline condition in a group of 52 typically developing 9-month-old human infants. Using the distribution characteristics (i.e., mean and variance) of the individual frontal EEG asymmetry scores, each infant was assigned to one of three asymmetry groups: Stable Right, Stable Left, and Variable. As predicted, infants in the Stable Right frontal asymmetry group exhibited a significantly higher baseline heart rate and were rated higher on maternal perception of fear at age 9 months compared with infants in the other two groups, replicating earlier work. These findings provide evidence of short-term stability (i.e., trait-like features) in frontal EEG asymmetry measures that index individual differences in infant temperament. Findings are discussed in terms of the utility of second-by-second frontal asymmetry scores to address developmental and maturational questions of individual differences in temperament.

Depressive disorders shows an alpha EEG asymmetry with higher activation in the left anterior brain. This phenomenon might be associated with the strengthened negative activities in the right side of the brain, especially the information related to self-concept. However, it is absent of direct evidence to support the relationship between the alpha EEG asymmetry and self-concept, and it is not clear what the variation of the correlation between the two factors in depressive disorders. To investigate the issues, we collected the resting EEG data with eye-closed and the self-consciousness level data to compare the relationship between alpha EEG asymmetry and self-concept in depression patients and healthy controls. Results show that both the two groups have strong correlations between the self-consciousness and alpha asymmetry in the brain, but differed in the correlation patterns. Depressions show that self-consciousness is correlated with the more anterior alpha EEG asymmetry in the brain, while the healthy group correlate with the more posterior alpha asymmetry. These results indicate that the impairment of the correlation between self-concept and alpha asymmetry in depressive disorders might be a biomarker of the disease to be considered in future study.

The aim of the current study was to investigate the effect of a naturalistic stressor, examination stress, on frontal EEG asymmetry, psychological stress, hormonal stress, and negative health. Forty-nine subjects were tested during periods of low and high examination stress. During the high examination stress period, subjects reported higher levels of stress on the Spielberger State Anxiety Inventory and Cohen's Perceived Stress Scale. However, no change in cortisol was detected across the two sessions. Furthermore, a shift from relatively greater left frontal activity during the low examination session to relatively greater right frontal activity during the high examination session was also found. Moreover, the increasing right frontal activity asymmetry associated with the high exam session compared to the low exam session correlated with increasing reports of negative health. No evidence was found for the prediction that cortisol mediated either the relationship between examination stressor and right frontal asymmetry or between right frontal asymmetry and negative health. In conclusion, while the findings from this study are compelling, the mechanism mediating increases in psychological stress, relatively greater right frontal activity, and increases in negative health from naturally occurring stressors is in need of further investigation.

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.

[Purpose] The purpose of this preliminary study was to investigate the effect of manual lymph drainage (MLD) of the neck on frontal electroencephalogram (EEG) asymmetry in subjects with psychological stress. [Subjects] Thirteen subjects with psychological stress participated in the study. [Methods] Subjects received MLD of the neck for 15 min. [Results] Analysis of the frontal asymmetry index showed that the energy shift in the alpha frequency band from the left hemisphere to the right hemisphere after MLD resulted in greater left-side activation (positive asymmetry values), which could be related to the positive emotional state observed particularly in the F7–F8 area. [Conclusion] These preliminary findings suggest that frontal EEG asymmetry was significantly attenuated after MLD.

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.