Resting frontal brain asymmetry is linked to future depressive symptoms in women

Greater weekly physical activity linked to left resting frontal alpha asymmetry in women: A study on gender differences in highly active young adults

Physical activity, beneficial for physical and psychological health, may facilitate affective mechanisms of positive emotion and approach-motivation. Greater resting frontal alpha asymmetry (FAA), an index of greater relative left than right frontal cortical activity, is a neural correlate of affective mechanisms possibly associated with active lifestyles. This study sought to amplify limited literature on the relationship between physical (in)activity, FAA, and gender differences. College students (n = 70) self-reported physical activity (Total PA) and sedentary activity (Total Sitting) via the International Physical Activity Questionnaire-Short Form (IPAQ-SF), followed by a resting electroencephalography session to record FAA. A Total PA × gender interaction (β = 0.462, t = 3.163, p = 0.002) identified a positive relationship between Total PA and FAA in women (β = 0.434, t = 2.221, p = 0.030) and a negative relationship for men (β = -0.338, t = -2.300, p = 0.025). Total Sitting was positively linked to FAA (β = 0.288, t = 2.228, p = 0.029; no gender effect). Results suggest affective mechanisms reflected by FAA (e.g., positive emotion, approach-motivation) are associated with physical activity for women, indicating a possible mechanism of the psychological benefits linked with physically active lifestyles. A positive relationship between sedentary behavior and greater left FAA may also reflect motivated mechanisms of behavior that aid in minimizing energy expenditure, particularly within the context of our highly active sample.

Behavioral state-dependent associations between EEG temporal correlations and depressive symptoms

Previous studies have shown abnormal long-range temporal correlations in neuronal oscillations among individuals with Major Depressive Disorders, occurring during both resting states and transitions between resting and task states. However, the understanding of this effect in preclinical individuals with depression remains limited. This study investigated the association between temporal correlations of neuronal oscillations and depressive symptoms during resting and task states in preclinical individuals, specifically focusing on male action video gaming experts. Detrended fluctuation analysis (DFA), Lifetimes, and Waitingtimes were employed to explore temporal correlations across long-range and short-range scales. The results indicated widespread changes from the resting state to the task state across all frequency bands and temporal scales. Rest-task DFA changes in the alpha band exhibited a negative correlation with depressive scores at most electrodes. Significant positive correlations between DFA values and depressive scores were observed in the alpha band during the resting state but not in the task state. Similar patterns of results emerged concerning maladaptive negative emotion regulation strategies. Additionally, short-range temporal correlations in the alpha band echoed the DFA results. These findings underscore the state-dependent relationships between temporal correlations of neuronal oscillations and depressive symptoms, as well as maladaptive emotion regulation strategies, in preclinical individuals.

Frontal alpha asymmetry during emotion regulation in adults with lifetime major depression

Emotion regulation (ER) often is impaired in current or remitted major depression (MD), although the extent of the deficits is not fully understood. Recent studies suggest that frontal alpha asymmetry (FAA) could be a promising electrophysiological measure to investigate ER. The purpose of this study was to investigate ER differences between participants with lifetime major depression (lifetime MD) and healthy controls (HC) for the first time in an experimental task by using FAA. We compared lifetime MD (n = 34) and HC (n = 25) participants aged 18-24 years in (a) an active ER condition, in which participants were instructed to reappraise negative images and (b) a condition in which they attended to the images while an EEG was recorded. We also report FAA results from an independent sample of adolescents with current MD (n = 36) and HC adolescents (n = 38). In the main sample, both groups were able to decrease self-reported negative affect in response to negative images through ER, without significant group differences. We found no differences between groups or conditions in FAA, which was replicated within the independent adolescent sample. The lifetime MD group also reported less adaptive ER in daily life and higher difficulty of ER during the task. The lack of differences between in self-reported affect and FAA between lifetime MD and HC groups in the active ER task indicates that lifetime MD participants show no impairments when instructed to apply an adaptive ER strategy. Implications for interventional aspects are discussed.

Frontal EEG alpha asymmetry in youth with autism: Sex differences and social-emotional correlates

In youth broadly, EEG frontal alpha asymmetry (FAA) associates with affective style and vulnerability to psychopathology, with relatively stronger right activity predicting risk for internalizing and externalizing behaviors. In autistic youth, FAA has been related to ASD diagnostic features and to internalizing symptoms. Among our large, rigorously characterized, sex-balanced participant group, we attempted to replicate findings suggestive of altered FAA in youth with an ASD diagnosis, examining group differences and impact of sex assigned at birth. Second, we examined relations between FAA and behavioral variables (ASD features, internalizing, and externalizing) within autistic youth, examining effects by sex. Third, we explored whether the relation between FAA, autism features, and mental health was informed by maternal depression history. In our sample, FAA did not differ by diagnosis, age, or sex. However, youth with ASD had lower total frontal alpha power than youth without ASD. For autistic females, FAA and bilateral frontal alpha power correlated with social communication features, but not with internalizing or externalizing symptoms. For autistic males, EEG markers correlated with social communication features, and with externalizing behaviors. Exploratory analyses by sex revealed further associations between youth FAA, behavioral indices, and maternal depression history. In summary, findings suggest that individual differences in FAA may correspond to social-emotional and mental health behaviors, with different patterns of association for females and males with ASD. Longitudinal consideration of individual differences across levels of analysis (e.g., biomarkers, family factors, and environmental influences) will be essential to parsing out models of risk and resilience among autistic youth.

Resting-state electroencephalography of neural oscillation and functional connectivity patterns in late-life depression

BACKGROUND

The clinical manifestations of late-life depression (LLD) are highly heterogeneous. Currently, abnormal characteristics of resting-state electroencephalography (EEG) power and functional connectivity are considered trait markers of depressive symptoms in major depression. However, the relationship between EEG spectral features and functional connectivity in LLD remains unknown.

METHODS

Forty-one patients with LLD and 44 participants without depression underwent an eyes-closed resting-state EEG. EEG power spectra, alpha asymmetry, and functional connectivity were calculated and analyzed.

RESULTS

Although alpha frontal asymmetry and cortical functional connectivity between the two groups showed no significant differences, the LLD group exhibited abnormal neural oscillation patterns of higher beta frequency activity in the parietal, central, and occipital lobes while alpha activity was increased in the parietal central electrodes.

LIMITATIONS

The number of EEG electrodes used in this study was low, and the sample size was limited.

CONCLUSIONS

Increased alpha and beta frequency band powers were observed in patients with LLD. These abnormal patterns may be associated with a disturbed balance of cortical excitation, inhibition, and hyperactivity. In the future, a neurofeedback protocol based on the findings of neural oscillation patterns in certain types of LLD should be explored.

The novel frontal alpha asymmetry factor and its association with depression, anxiety, and personality traits

Frontal alpha asymmetry (FAA) is widely examined in EEG research, yet a procedural consensus on its assessment is lacking. In this study, we tested a latent factorial approach to measure FAA. We assessed resting-state FAA at broad, low, and high alpha bands (8-13; 8-10.5; and 11-13 Hz) using mastoids as reference electrodes and Current Source Density (CSD) transformation (N = 139 non-clinical participants). From mastoid-referenced data, we extracted a frontal alpha asymmetry factor (FAAf) and a parietal factor (PAAf) subjecting all asymmetry indices to a varimax-rotated, principal component analysis. We explored split-half reliability and discriminant validity of the mastoid factors and the mastoid and CSD raw asymmetry indices (F3/4, F7/8, P3/4, and P7/8). Both factor and raw scores reached an excellent split-half reliability (>.99), but only the FAAf reached the maximum discriminant validity from parietal scores. Next, we explored the correlations of latent factor and raw FAA scores with symptoms of depression, anxiety, and personality traits to determine which associations were driven by FAA after variance from parietal activity was removed. After correcting for false discovery rate, only FAAf at the low alpha band was negatively associated with depression symptoms (a latent CES-D factor) and significantly diverged from PAAf's association with depression symptoms. With respect to personality traits, only CSD-transformed F7/8 was positively correlated with Conscientiousness and significantly diverged from the correlations between Conscientiousness and P3/4 and P7/8. Overall, the latent factor approach shows promise for isolating functionally distinct resting-state EEG signatures, although further research is needed to examine construct validity.

A comparison of nomothetic and individualized alpha frequency approaches to measuring frontal EEG alpha asymmetry

Frontal alpha asymmetry (FAA) is considered to be a reliable marker of affective processing and psychopathology. Traditionally, the magnitude of alpha is calculated by taking the average over a nomothetic fixed frequency window (e.g., 8 to 13 Hz). Alternatively, methods have been proposed to extract individualized alpha frequency (IAF) peaks and windows in hopes of improving the reliability and validity of signal detection. However, no study has compared the nomothetic to IAF approaches to examine the reliability and validity of resting FAA in a large well-characterized data set. In this study, we assessed the psychometric performance of the standard fixed window approach, a PZ-alpha based IAF approach and a global-alpha based IAF windows detection approach on a previously collected EEG data set (8 recordings per subject collected on four occasions across two weeks). Our results revealed that resting FAA calculated with these three different methods are highly correlated at all frontal regions (mean r = .98). The stability across the 8 recordings over the two weeks also showed no substantial difference between approaches as indicated by intraclass correlations. Moreover, internal-consistency reliability, validity with respect to measures of emotion and emotion-related psychopathology and state-trait Structure equation model (SEM) fitting were evaluated and yielded no significant differences across methods. Our results supported the overall reliability and validity of two different IAF approaches to assessing resting FAA but fail to find any incremental advantage over nomothetic approaches to defining alpha bands. Guidelines for methods selection for future research are provided.

Characteristics of single-channel electroencephalogram in depression during conversation with noise reduction technology

Background

Previous studies have attempted to characterize depression using electroencephalography (EEG), but results have been inconsistent. New noise reduction technology allows EEG acquisition during conversation.

Methods

We recorded EEG from 40 patients with depression as they engaged in conversation using a single-channel EEG device while conducting real-time noise reduction and compared them to those of 40 healthy subjects. Differences in EEG between patients and controls, as well as differences in patients’ depression severity, were examined using the ratio of the power spectrum at each frequency. In addition, the effects of medications were examined in a similar way.

Results

In comparing healthy controls and depression patients, significant power spectrum differences were observed at 3 Hz, 4 Hz, and 10 Hz and higher frequencies. In the patient group, differences in the power spectrum were observed between asymptomatic patients and healthy individuals, and between patients of each respective severity level and healthy individuals. In addition, significant differences were observed at multiple frequencies when comparing patients who did and did not take antidepressants, antipsychotics, and/or benzodiazepines. However, the power spectra still remained significantly different between non-medicated patients and healthy individuals.

Limitations

The small sample size may have caused Type II error. Patients’ demographic characteristics varied. Moreover, most patients were taking various medications, and cannot be compared to the non-medicated control group.

Conclusion

A study with a larger sample size should be conducted to gauge reproducibility, but the methods used in this study could be useful in clinical practice as a biomarker of depression.

The effectiveness of emotion cognitive reappraisal as measured by self-reported response and its link to EEG alpha asymmetry

Cognitive reappraisal is an important emotion regulation skill for psychological health and well-being, however, some people cannot use this strategy effectively. We investigated EEG alpha asymmetry by calculating lateral index (LI) when twenty-six healthy participants were instructed to complete the emotion cognitive reappraisal task of viewing neutral pictures, watching negative pictures and reappraising negative pictures. According to self-reported valence and arousal, the participants were divided into effective and ineffective groups. Habitual use of rumination was also assessed using the Cognitive Emotion Regulation Questionnaire (CERQ). EEG alpha asymmetry results demonstrated that, ineffective group showed greater relative right temporal activity than effective group in the early stage of reappraisal, indicating higher subjective arousal. Both groups showed greater relative left frontal alpha activity in the late stages of reappraisal compared with watching negative images, indicating the recruitment of corresponding functions in prefrontal regulatory circuitry during the effort of reappraisal. CERQ analysis results showed that, ineffective group got significantly higher score than effective group in habitual use of rumination. Partial correlation revealed that, in male participants, temporal LI change (negative-reappraisal minus negative-watch) was negatively correlated with self-reported arousal and habitual use of rumination. In addition, by using K-means cluster analysis, temporal LI combined with CERQ-rumination score achieved a classification accuracy of 84.6 %. These findings suggested that, EEG alpha asymmetry as well as the habitual use of rumination accounted for the reappraisal effectiveness.

Women with Major Depressive Disorder, Irrespective of Comorbid Anxiety Disorders, Show Blunted Bilateral Frontal Responses during Win and Loss Anticipation

BACKGROUND

Electroencephalography (EEG) studies suggest that major depressive disorder (MDD) is associated with lower left than right frontal brain activity (asymmetry), a pattern appearing stronger in women than men, and when elicited during emotionally-relevant paradigms versus an uncontrolled resting state. However, it is unclear whether this asymmetry pattern generalizes to the common presentation of MDD with co-occurring anxiety. Moreover, asymmetry may differ for anxiety subtypes, wherein anxious apprehension (AnxApp: worry characteristic of generalized anxiety disorder) appears left-lateralized, but anxious arousal (AnxAro: panic characteristic of social anxiety, posttraumatic stress, and panic disorders) may be right-lateralized.

METHODS

This analysis attempted to replicate frontal EEG asymmetry patterns using functional magnetic resonance imaging (fMRI). Participants completed clinical interviews and a monetary incentive delay (MID) task during fMRI recording. We compared five groups of right-handed women from the Tulsa 1000 study, MDD (n=40), MDD-AnxApp (n=26), MDD-AnxAro (n=34), MDD-Both (with AnxApp and AnxAro; n=26), and healthy controls (CTL; n=24), as a function of MID anticipation condition (no win/loss, win, loss) and hemisphere on frontal blood oxygen-level-dependent (BOLD) signal.

RESULTS

CTL exhibited higher bilateral superior, middle, and inferior middle frontal gyrus BOLD signal than the four MDD groups for high arousal (win and loss) conditions. However, frontal attenuations were unrelated to current depression/anxiety symptoms, suggestive of a trait as opposed to a state marker.

LIMITATIONS

This was a cross-sectional analysis restricted to women.

CONCLUSIONS

Reduced prefrontal cortex recruitment during processing of both positively and negatively valenced stimuli is consistent with the emotion context insensitivity theory of MDD.

Nervous and Endocrine System Dysfunction in Posttraumatic Stress Disorder: An Overview and Consideration of Sex as a Biological Variable

Decades of research into the biological mechanisms of posttraumatic stress disorder (PTSD) suggests that chronic activation of the stress response leads to long-lasting changes in the structure and function of the nervous and endocrine systems. While the prevalence of PTSD is twice as high in females as males, little is known about how sex differences in neuroendocrine systems may contribute to PTSD. In response to the paucity of research on sex-related mechanisms, the National Institutes of Health created a policy that asks researchers to consider sex as a biological variable. This review provides an overview of the current understanding of nervous and endocrine dysfunction in PTSD (e.g., neural circuitry, autonomic arousal, hormonal response), highlighting areas where the influence of sex has been characterized and where further research is needed. We also provide recommendations for using the sex-as-a-biological-variable policy to address specific gaps in PTSD neuroscience research.

Microstates-based resting frontal alpha asymmetry approach for understanding affect and approach/withdrawal behavior

The role of resting frontal alpha-asymmetry in explaining neural-mechanisms of affect and approach/withdrawal behavior is still debatable. The present study explores the ability of the quasi-stable resting EEG asymmetry information and the associated neurovascular synchronization/desynchronization in bringing more insight into the understanding of neural-mechanisms of affect and approach/withdrawal behavior. For this purpose, a novel frontal alpha-asymmetry based on microstates, that assess quasi-stable EEG scalp topography information, is proposed and compared against standard frontal-asymmetry. Both proposed and standard frontal alpha-asymmetries were estimated from thirty-nine healthy volunteers resting-EEG simultaneously acquired with resting-fMRI. Further, neurovascular mechanisms of these asymmetry measures were estimated through EEG-informed fMRI. Subsequently, the Hemodynamic Lateralization Index (HLI) of the neural-underpinnings of both asymmetry measures was assessed. Finally, the robust correlation of both asymmetry-measures and their HLI’s with PANAS, BIS/BAS was carried out. The standard resting frontal-asymmetry and its HLI yielded no significant correlation with any psychological-measures. However, the microstate resting frontal-asymmetry correlated significantly with negative affect and its neural underpinning’s HLI significantly correlated with Positive/Negative affect and BIS/BAS measures. Finally, alpha-BOLD desynchronization was observed in neural-underpinning whose HLI correlated significantly with negative affect and BIS. Hence, the proposed resting microstate-frontal asymmetry better assesses the neural-mechanisms of affect, approach/withdrawal behavior.

Neuroimaging predictors of onset and course of depression in childhood and adolescence: A systematic review of longitudinal studies

Major depressive disorder (MDD) often emerges during adolescence with detrimental effects on development as well as lifetime consequences. Identifying neurobiological markers that are associated with the onset or course of this disorder in childhood and adolescence is important for early recognition and intervention and, potentially, for the prevention of illness onset. In this systematic review, 68 longitudinal neuroimaging studies, from 34 unique samples, that examined the association of neuroimaging markers with onset or changes in paediatric depression published up to 1 February 2019 were examined. These studies employed different imaging modalities at baseline; structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), functional MRI (fMRI) or electroencephalography (EEG). Most consistent evidence across studies was found for blunted reward-related (striatal) activity (fMRI and EEG) as a potential biological marker for both MDD onset and course. With regard to structural brain measures, the results were highly inconsistent, likely caused by insufficient power to detect complex mediating effects of genetic and environmental factors in small sample sizes. Overall, there were a limited number of samples, and confounding factors such as sex and pubertal development were often not considered, whereas these factors are likely to be relevant especially in this age range.

Does frontal brain activity mediate the effect of depression prevention in adolescents? A pilot study

We investigated whether (a) depression prevention was associated with depressive symptoms and medial-frontal alpha asymmetry in adolescents; (b) alpha asymmetry mediated the association between participation in a prevention program and depressive symptoms; and (c) gender affects these associations. In our randomised control group study, we compared a universal prevention program (n = 40 adolescents, 14 females) with a non-intervention control condition (n = 39 adolescents, 20 females) in German secondary school students (mean age: 13.53 years, SD = 0.53). We collected data at baseline, post-intervention, 6-month, and 12-month follow-up using the Self-Rating Questionnaire for Depressive Disorders (SBB-DES) and resting medial-frontal alpha activity on F3 and F4. We found that girls benefitted from participating in the prevention program in regards to their depressive symptoms at 12-month follow-up but not alpha asymmetry. In boys, participation in the prevention program was associated with their alpha asymmetry at 6-month follow-up but not their depressive symptoms. Alpha asymmetry did not mediate the effects of the prevention program on depressive symptoms in either gender. Although participation in the prevention program was associated with both depressive symptoms and alpha asymmetry, those associations seem independent from each other. Possible explanations for this result pattern are discussed.

The Electrical Aftermath: Brain Signals of Posttraumatic Stress Disorder Filtered Through a Clinical Lens

This review aims to identify patterns of electrical signals identified using electroencephalography (EEG) linked to posttraumatic stress disorder (PTSD) diagnosis and symptom dimensions. We filter EEG findings through a clinical lens, evaluating nuances in findings according to study criteria and participant characteristics. Within the EEG frequency domain, greater right than left parietal asymmetry in alpha band power is the most promising marker of PTSD symptoms and is linked to exaggerated physiological arousal that may impair filtering of environmental distractors. The most consistent findings within the EEG time domain focused on event related potentials (ERPs) include: 1) exaggerated frontocentral responses (contingent negative variation, mismatch negativity, and P3a amplitudes) to task-irrelevant distractors, and 2) attenuated parietal responses (P3b amplitudes) to task-relevant target stimuli. These findings suggest that some individuals with PTSD suffer from attention dysregulation, which could contribute to problems concentrating on daily tasks and goals in lieu of threatening distractors. Future research investigating the utility of alpha asymmetry and frontoparietal ERPs as diagnostic and predictive biomarkers or intervention targets are recommended.

Altered Gamma-Band Activity as a Potential Biomarker for the Recurrence of Major Depressive Disorder

Background: The neurophysiological mechanisms of cognitive reactivity, the primary vulnerability factor of major depressive disorder (MDD) recurrence, remain unclear in individuals with recovered MDD (rMDD). Because gamma-band responses (GBRs) can be used to measure cognitive processing, they may also be useful for elucidating the mechanisms underlying cognitive reactivity. Identifying these mechanisms may permit the development of an index for predicting and preempting MDD recurrence. Here, to identify the neurophysiological mechanisms of cognitive reactivity, we examined the characteristics of the GBRs evoked/induced by emotional words in participants with and without rMDD after inducing a negative mood. Methods: Thirty-three healthy control participants and 18 participants with rMDD completed a lexical emotion identification task during electroencephalography along with assessments of cognitive reactivity after negative mood induction. Results: No between-group differences were identified for the task reaction times; however, the rMDD group had significantly higher cognitive reactivity scores than did the control group. Furthermore, the power of late GBRs to positive words was significantly greater in the rMDD group, with the greater power of late GBRs being related to higher cognitive reactivity. Limitations: Considering the population studied, our findings cannot be completely generalized to populations other than adolescents, people with rMDD, and those without a history of co-morbid disorders and early life stress. Conclusions: Our findings indicate that the dysfunction of neural circuits related to higher-order processes like memory and attention might underlie cognitive reactivity. Altered late GBRs to positive information may be persistent biomarkers of the depression recurrence risk.