Trait anxiety impact on posterior activation asymmetries at rest and during evoked negative emotions: EEG investigation

Altered Functional Brain Network Structure between Patients with High and Low Generalized Anxiety Disorder

To investigate the differences in functional brain network structures between patients with a high level of generalized anxiety disorder (HGAD) and those with a low level of generalized anxiety disorder (LGAD), a resting-state electroencephalogram (EEG) was recorded in 30 LGAD patients and 21 HGAD patients. Functional connectivity between all pairs of brain regions was determined by the Phase Lag Index (PLI) to construct a functional brain network. Then, the characteristic path length, clustering coefficient, and small world were calculated to estimate functional brain network structures. The results showed that the PLI values of HGAD were significantly increased in alpha2, and significantly decreased in the theta and alpha1 rhythms, and the small-world attributes for both HGAD patients and LGAD patients were less than one for all the rhythms. Moreover, the small-world values of HGAD were significantly lower than those of LGAD in the theta and alpha2 rhythms, which indicated that the brain functional network structure would deteriorate with the increase in generalized anxiety disorder (GAD) severity. Our findings may play a role in the development and understanding of LGAD and HGAD to determine whether interventions that target these brain changes may be effective in treating GAD.

Difference analysis of multidimensional electroencephalogram characteristics between young and old patients with generalized anxiety disorder

Growing evidences indicate that age plays an important role in the development of mental disorders, but few studies focus on the neuro mechanisms of generalized anxiety disorder (GAD) in different age groups. Therefore, this study attempts to reveal the neurodynamics of Young_GAD (patients with GAD under the age of 50) and Old_GAD (patients with GAD over 50 years old) through statistical analysis of multidimensional electroencephalogram (EEG) features and machine learning models. In this study, 10-min resting-state EEG data were collected from 45 Old_GAD and 33 Young_GAD. And multidimensional EEG features were extracted, including absolute power (AP), fuzzy entropy (FE), and phase-lag-index (PLI), on which comparison and analyses were performed later. The results showed that Old_GAD exhibited higher power spectral density (PSD) value and FE value in beta rhythm compared to theta, alpha1, and alpha2 rhythms, and functional connectivity (FC) also demonstrated significant reorganization of brain function in beta rhythm. In addition, the accuracy of machine learning classification between Old_GAD and Young_GAD was 99.67%, further proving the feasibility of classifying GAD patients by age. The above findings provide an objective basis in the field of EEG for the age-specific diagnosis and treatment of GAD.

A Review of AI Cloud and Edge Sensors, Methods, and Applications for the Recognition of Emotional, Affective and Physiological States

Affective, emotional, and physiological states (AFFECT) detection and recognition by capturing human signals is a fast-growing area, which has been applied across numerous domains. The research aim is to review publications on how techniques that use brain and biometric sensors can be used for AFFECT recognition, consolidate the findings, provide a rationale for the current methods, compare the effectiveness of existing methods, and quantify how likely they are to address the issues/challenges in the field. In efforts to achieve the key goals of Society 5.0, Industry 5.0, and human-centered design better, the recognition of emotional, affective, and physiological states is progressively becoming an important matter and offers tremendous growth of knowledge and progress in these and other related fields. In this research, a review of AFFECT recognition brain and biometric sensors, methods, and applications was performed, based on Plutchik's wheel of emotions. Due to the immense variety of existing sensors and sensing systems, this study aimed to provide an analysis of the available sensors that can be used to define human AFFECT, and to classify them based on the type of sensing area and their efficiency in real implementations. Based on statistical and multiple criteria analysis across 169 nations, our outcomes introduce a connection between a nation's success, its number of Web of Science articles published, and its frequency of citation on AFFECT recognition. The principal conclusions present how this research contributes to the big picture in the field under analysis and explore forthcoming study trends.

A Combination of Green Tea, Rhodiola, Magnesium, and B Vitamins Increases Electroencephalogram Theta Activity During Attentional Task Performance Under Conditions of Induced Social Stress

Background

A combination of green tea, rhodiola and magnesium with B vitamins has previously been reported to significantly increase EEG resting state theta, attenuate subjective stress, anxiety and mood disturbance, and heighten subjective and autonomic arousal under acute psychosocial laboratory stress. Here we examine the capacity of green tea and rhodiola extract administered in combination or in isolation with magnesium and B vitamins to moderate spectral brain activity during attentional task performance under stress.

Materials and Methods

One-hundred moderately stressed adults received oral supplementation of (i) Mg + B vitamins + green tea + rhodiola; (ii) Mg + B vitamins + rhodiola; (iii) Mg + B vitamins + green tea; or (iv) placebo, in a double-blind, randomised, placebo-controlled, parallel-group design (Clinicaltrials.gov: NCT03262376; 25/0817). Participants completed an attention switching and emotionally threatening attentional bias task after stress induction (Trier Social Stress Test). Spectral alpha and theta brain activity and event related potentials (ERPs) were recorded during cognitive task performance by electroencephalogram (EEG; BioSemi ActiveTwo 64 channel).

Results

The combined treatment of Mg + B vitamins + green tea + rhodiola significantly increased frontal midline theta vs. placebo and rhodiola in isolation during the attention switching task, specifically in anticipation of a change in task performance parameter. The combined treatment also significantly increased contralateral theta activation in relation to viewing emotionally threatening images in the left (vs. placebo and rhodiola in isolation) and right parietal (vs. placebo) regions. Further, this treatment demonstrated significantly heightened ipsilateral left parietal theta activation in relation to viewing emotionally threatening images. The combined treatment attenuated a decrease in alpha power during the attentional bias task evident in comparator treatments, but this did not reach significance. No significant effects of treatments on behavioural performance or ERP were found.

Conclusion

The combination of Mg + B vitamins + green tea + rhodiola increased spectral theta brain activity during the execution of two attentional tasks suggestive of a potential to increase attentional capacity under conditions of stress. Further examination of these ingredients in relation to attentional performance under stress is warranted to ascertain if functional benefits suggested by theta activation can be shown behaviourally.

Transcranial Direct Current Stimulation Over the Left Dorsolateral Prefrontal Cortex Reduced Attention Bias Toward Negative Facial Expression: A Pilot Study in Healthy Subjects

Research in the cognitive neuroscience field has shown that individuals with a stronger attention bias for negative information had higher depression risk, which may be the underlying pathogenesis of depression. This dysfunction of affect-biased attention also represents a decline in emotion regulation ability. Clinical studies have suggested that transcranial direct current stimulation (tDCS) treatment can improve the symptoms of depression, yet the neural mechanism behind this improvement is still veiled. This study aims to investigate the effects of tDCS on affect-biased attention. A sample of healthy participants received 20 min active (n = 22) or sham tDCS (n = 19) over the left dorsolateral prefrontal cortex (DLPFC) for 7 consecutive days. Electroencephalographic (EEG) signals were recorded while performing the rest task and emotional oddball task. The oddball task required response to pictures of the target (positive or negative) emotional facial stimuli and neglecting distracter (negative or positive) or standard (neutral) stimuli. Welch power spectrum estimation algorithm was applied to calculate frontal alpha asymmetry (FAA) in the rest task, and the overlapping averaging method was used to extract event-related potentials (ERP) components in the oddball task. Compared to sham tDCS, active tDCS caused an obvious increment in FAA in connection with emotion regulation (p < 0.05). Also, participants in the active tDCS group show greater P3 amplitudes following positive targets (p < 0.05) and greater N2 amplitudes following negative distracters (p < 0.05), reflecting emotion-related attention biases. These results offer valuable insights into the relationship between affect-biased attention and the effects of tDCS, which may be of assistance in exploring the neuropathological mechanism of depression and anxiety and new treatment strategies for tDCS.

Dysregulated brain salience within a triple network model in high trait anxiety individuals: A pilot EEG functional connectivity study

Although previous studies have reported the association between large-scale brain networks alterations and pathological anxiety, abnormalities in the dynamic interaction among the triple network model in anxiety disorders and, especially, in trait anxiety is still poorly explored. Thus, the main aim of the current study was to investigate triple network functional dynamics in subjects with high trait anxiety during resting state (RS) through electroencephalography (EEG) connectivity. Twenty-three individuals with high-trait-anxiety (HTA) and forty-five participants with low-trait-anxiety (LTA) were enrolled. EEG analyses were conducted by means of the exact Low-Resolution Electromagnetic Tomography software (eLORETA). Compared to LTA participants, HTA subjects showed a decrease of alpha connectivity within the salience network (SN), between the dorsal anterior cingulate cortex (dACC) and both left and right anterior insula (AI). Furthermore, SN functional connectivity strength was negatively correlated with higher trait anxiety, even when controlling for potential confounding variables (e.g., depressive and obsessive-compulsive symptoms). Taken together, our results point out a specific functional connectivity pattern in HTA individuals, which consists in a dysfunctional communication within the SN, specifically in the AI-dACC pathway. This functional pattern could underline, at rest, saliency detection and brain correlates of altereted emotion regulation and cognitive control processes typically involved in anxiety.

Sleepiness, Exertion Fatigue, Arousal, and Vigilant Attention in Persons With Chronic Aphasia

Purpose Individuals in the acute and chronic stages of stroke recovery often report more daytime sleepiness (Sterr, Herron, Dijk, & Ellis, 2008) and fatigue that qualitatively differs from "normal" feelings of fatigue they experienced prestroke (De Doncker, Dantzer, Ormstad, & Kuppuswamy, 2018). Speech-language pathologists frequently observe signs of fatigue in their clients with aphasia and perceive that client fatigue impedes therapeutic interventions (Riley, 2017). The current study aimed to quantify daytime sleepiness, exertion fatigue, and physiologically measured arousal and vigilant attention in persons with aphasia. Method We measured sleepiness, exertion fatigue, arousal, and vigilant attention in 10 participants with aphasia and 10 neurologically healthy adults. Daytime sleepiness was measured using the Epworth Sleepiness Scale (Johns, 1991). Exertion fatigue was measured using the Visual Analog Fatigue Scale (B. Y. Tseng, Gajewski, & Kluding, 2010) before and after a 72-min computer-administered language task. Arousal was measured using heart rate and variability (Shaffer & Ginsberg, 2017). Vigilant attention was measured using electroencephalography and subsequently classified into 1 of 4 levels of vigilant attention using a classification algorithm (Berka et al., 2004). Results Persons with aphasia did not show significant differences from controls in reported amount of daytime sleepiness, exertion fatigue, or overall physiological arousal but demonstrated different patterns of electroencephalography-measured vigilant attention and error production as compared to controls. Conclusions Although overall sleepiness, exertion fatigue, and overall arousal did not differ between groups, physiological measures of vigilant attention may be more sensitive to differences and may explain feelings of fatigue that persons with chronic aphasia experience.

Antismoking Campaigns' Perception and Gender Differences: A Comparison among EEG Indices

Human factors' aim is to understand and evaluate the interactions between people and tasks, technologies, and environment. Among human factors, it is possible then to include the subjective reaction to external stimuli, due to individual's characteristics and states of mind. These processes are also involved in the perception of antismoking public service announcements (PSAs), the main tool for governments to contrast the first cause of preventable deaths in the world: tobacco addiction. In the light of that, in the present article, it has been investigated through the comparison of different electroencephalographic (EEG) indices a typical item known to be able of influencing PSA perception, that is gender. In order to investigate the neurophysiological underpinnings of such different perception, we tested two PSAs: one with a female character and one with a male character. Furthermore, the experimental sample was divided into men and women, as well as smokers and nonsmokers. The employed EEG indices were the mental engagement (ME: the ratio between beta activity and the sum of alpha and theta activity); the approach/withdrawal (AW: the frontal alpha asymmetry in the alpha band); and the frontal theta activity and the spectral asymmetry index (SASI: the ratio between beta minus theta and beta plus theta). Results suggested that the ME and the AW presented an opposite trend, with smokers showing higher ME and lower AW than nonsmokers. The ME and the frontal theta also evidenced a statistically significant interaction between the kind of the PSA and the gender of the observers; specifically, women showed higher ME and frontal theta activity for the male character PSA. This study then supports the usefulness of the ME and frontal theta for purposes of PSAs targeting on the basis of gender issues and of the ME and the AW and for purposes of PSAs targeting on the basis of smoking habits.

Default mode network alterations in individuals with high-trait-anxiety: An EEG functional connectivity study

BACKGROUND

Although several researches investigated Default Mode Network (DMN) alterations in individuals with anxiety disorders, up to now no studies have investigated DMN functional connectivity in non-clinical individuals with high-trait-anxiety using quantitative electroencephalography (EEG). Here, the main aim was to extend previous findings investigating the association between trait anxiety and DMN EEG functional connectivity.

METHODS

Twenty-three individuals with high-trait-anxiety and twenty-four controls were enrolled. EEG was recorded during 5 min of resting state (RS). EEG analyses were conducted by means of the exact Low-Resolution Electromagnetic Tomography software (eLORETA).

RESULTS

Compared to controls, individuals with high-trait-anxiety showed a decrease of theta connectivity between right medial prefrontal cortex (mPFC) and right posterior cingulate/retrosplenial cortex. A decrease of beta connectivity was also observed between right mPFC and right anterior cingulate cortex. Furthermore, DMN functional connectivity strength was negatively related with STAI-T total score (i.e., lower connectivity was associated with higher trait anxiety), even when controlling for potential confounding variables (i.e., sex, age, and general psychopathology).

LIMITATIONS

Small sample size makes it difficult to draw definitive conclusions. Furthermore, we did not assess state variation of anxiety, which make our interpretation specific to trait anxiety.

CONCLUSIONS

Taken together, our results suggest that high-trait-anxiety individuals fail to synchronize DMN during RS, reflecting a possible top-down cognitive control deficit. These results may help in the understanding of the individual differences in functional brain networks associated with trait anxiety, a crucial aim in the prevention and in the early etiology understanding of clinical anxiety and related sequelae.

Effect of negative and positive emotions on EEG spectral asymmetry

The aim of the study was to evaluate the applicability of electroencephalogram (EEG) spectral asymmetry index (SASI) for discrimination of the effect of negative and positive emotions on human brain bioelectrical activity. SASI has been previously proposed as a method to detect depression based on the balance of EEG theta and beta frequency band powers. Emotions were evoked on 22 healthy subjects using emotional pictures portraying humans from International Affective Picture System (IAPS) and late response to stimuli was examined (1700-2200 ms). Electroencephalogram (EEG) was recorded in 30 channels divided into 10 brain regions: left frontal, right frontal, left temporal, right temporal, frontal, frontocentral, central, centroparietal, parietal and occipital. Negative stimuli, compared to neutral stimuli, significantly increased SASI in frontocentral, central, centroparietal, parietal and occipital areas. Positive stimuli, compared to neutral stimuli, significantly decreased SASI in left temporal, centroparietal, parietal and occipital areas. The results indicate that SASI provides a good discrimination between the effects of negative, neutral and positive emotions on human EEG.

Negative affectivity and EEG asymmetry interact to predict emotional interference on attention in early school-aged children

Negative affectivity (NA) is a broad construct that has been associated with the development of psychopathologies, such as anxiety, and with exaggerated attention to threatening stimuli. EEG asymmetry reflects biological individual differences in emotional reactivity that may underlie the association between NA and attention to threat. The present study included a sample of 31 five-seven year olds (M age in months=74.39, SD=6.57) to test the hypothesis that greater NA, combined with greater right anterior and posterior asymmetries, predicts increased attention interference following threat stimuli. Children completed an executive attention task which presented task-irrelevant threat (angry) and non-threat (neutral) faces prior to each trial. EEG asymmetry was measured at baseline for anterior, anterior-temporal and posterior scalp regions and child NA was measured via maternal report. As predicted, children showing greater NA and greater right anterior-temporal asymmetry showed more attention interference following angry faces. Additionally, two trend-level effects emerged: children showing greater NA and greater left anterior-temporal asymmetry showed less attention interference following angry faces, and children showing greater NA and greater left posterior asymmetry showed less attention interference, but only following neutral faces. Discussion focuses on the utility of using EEG asymmetry in the study of temperament, attentional biases, and the biological processes by which temperament confers risk for psychopathology.

EEG changes caused by spontaneous facial self-touch may represent emotion regulating processes and working memory maintenance

Spontaneous facial self-touch gestures (sFSTG) are performed manifold every day by every human being, primarily in stressful situations. These movements are not usually designed to communicate and are frequently accomplished with little or no awareness. The aim of the present study was to investigate whether sFSTG are associated with specific changes in the electrical brain activity that might indicate an involvement of regulatory emotional processes and working memory. Fourteen subjects performed a delayed memory task of complex haptic stimuli. The stimuli had to be explored and then remembered for a retention interval of 5min. The retention interval was interrupted by unpleasant sounds from The International Affective Digitized Sounds and short sound-free periods. During the experiment a video stream of behavior, 19-channel EEG, and EMG (of forearm muscles) were recorded. Comparisons of the behavioral data and spectral power of different EEG frequency bands (theta, alpha, beta, and gamma) were conducted. An increase of sFSTG during the application of unpleasant sounds was observed. A significant increase of spectral theta and beta power was observed after exploration of the stimuli as well as after sFSTG in centro-parietal electrodes. The spectral theta power extremely decreased just before sFSTG during the retention interval. Contrary to this, no significant changes were detected in any of the frequencies when the spectral power before and after instructed facial self-touch movements (b-iFSTG and a-iFSTG) were compared. The changes of spectral theta power in the intervals before and after sFSTG in centro-parietal electrodes imply that sFSTG are associated with cortical regulatory processes in the domains of working memory and emotions.

Resting-state oscillatory activity in autism spectrum disorders

Neural oscillatory anomalies in autism spectrum disorders (ASD) suggest an excitatory/inhibitory imbalance; however, the nature and clinical relevance of these anomalies are unclear. Whole-cortex magnetoencephalography data were collected while 50 children (27 with ASD, 23 controls) underwent an eyes-closed resting-state exam. A Fast Fourier Transform was applied and oscillatory activity examined from 1 to 120 Hz at 15 regional sources. Associations between oscillatory anomalies and symptom severity were probed. Children with ASD exhibited regionally specific elevations in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and high frequency (20-120 Hz) power, supporting an imbalance of neural excitation/inhibition as a neurobiological feature of ASD. Increased temporal and parietal alpha power was associated with greater symptom severity and thus is of particular interest.

Alpha activity in the insula accompanies the urge to neutralize in sub-clinical obsessive-compulsive participants

Background and aims The behavioural addiction model of obsessive-compulsive disorder (OCD) proposes that as compulsions successfully reduce obsession-provoked anxiety in the early stages of the disorder, their performance is rewarding and therefore potentially addictive. According to this theory, the urge to perform a compulsion or neutralization resembles craving in addiction, and ventral fronto-striatal reward circuitry is activated during compulsive or neutralizing behaviour, resembling substance addiction disorders. The current study used EEG source localisation to test this hypothesis by examining brain activity accompanying the urge to neutralize and covert neutralization. Methods Two groups of non-clinical participants (15 Low-OC, 15 High-OC) performed a task in which the urge to neutralize was induced by supplying participants with an obsessive-compulsive-like thought. Source localised EEG activity was compared between a negative condition with high urge to neutralize, and a positive condition with low urge to neutralize, and correlations between brain activity and self-reported urge to neutralize were examined. Results High-OC participants reported a significantly greater urge to neutralize than Low-OC participants, and the majority of participants reported performing covert neutralization during the experiment. Between-condition comparisons in the High-OC group revealed significantly greater alpha activity in the insula and vlPFC in the negative than the positive condition, which was significantly correlated with both urge to neutralize and later decrease in negative affect. Conclusions The current results support the proposal that the urge to neutralize in OCD is neurally similar to craving in substance addiction, in agreement with the behavioural addiction model of OCD.

Frontal brain electrical asymmetry and cardiac vagal tone predict biased attention to social threat

Individual differences in attention biases for motivationally significant stimuli have been reported in clinical and normative populations. Few studies, however, have attempted to examine potential biological mechanisms underlying differences in the cognitive processing of emotional stimuli. The present study examined the extent to which two well-validated psychophysiological vulnerability markers of affective style [i.e., frontal electroencephalogram (EEG) asymmetry and cardiac vagal tone] predicted biased attention toward rapid presentations (approximately 250 ms) of angry and happy facial expressions. We found that right frontal EEG asymmetry and low cardiac vagal tone, taken together, predicted approximately 37% of the variability in attentional vigilance for angry faces. Frontal EEG asymmetry and cardiac vagal tone did not predict attention for happy faces, independently of each other. Our results provide preliminary evidence that two well established psychophysiological indicators of affective style bias early processing of motivationally salient stimuli.

Tobacco smoking produces widespread dominant brain wave alpha frequency increases

The major pharmacological ingredient in tobacco smoke is nicotine, a mild stimulant known to alter brain electrical activity. The objective of this study was to determine if tobacco smoking in humans produces localized or widespread neocortical dominant alpha electroencephalographic (EEG) frequency increases consistent with nicotine stimulation of the brainstem activating system in animals. Twenty-two male volunteer non-deprived tobacco smokers were studied. They were asked not to smoke for at least 1h before the experiment in mid-morning as part of their usual smoking schedule. In the laboratory, they sham smoked and then smoked their favorite tobacco cigarette. Two experimental sessions (#1 and #2) were conducted, separated by a one to two month interval. In both sessions, there were minor statistically significant increases in the dominant alpha frequencies after sham smoking. In both sessions, after the subjects smoked a favorite tobacco cigarette there was a significant generalized increase in dominant alpha EEG frequencies in most scalp recording sites. This study demonstrates that tobacco smoking produces widespread bilateral neocortical increases in dominant alpha EEG frequencies consistent with the stimulant effects of nicotine on the brainstem reticular activating system.

A meta-analysis of reinforcement sensitivity theory: on performance parameters in reinforcement tasks

J. A. Gray's Reinforcement Sensitivity Theory (RST) has produced a wealth of quasi-experimental studies in more than 35 years of research on personality and reinforcement sensitivity. The present meta-analysis builds on this literature by investigating RST in conflict and nonconflict reinforcement tasks in humans. Based on random-effects meta-analysis, we confirmed RST predictions of performance parameters (e.g., number of responses, reaction time) in reinforcement tasks for impulsivity- and anxiety-related traits. In studies on anxiety-related traits, the effect size variance was smaller for conflict tasks than for nonconflict tasks. A larger mean effect size and a larger variability of effect sizes were found for conflict compared to nonconflict tasks in studies on impulsivity-related traits. Our results suggest that problems with RST confirmation in reinforcement tasks are at least partly caused by insufficient statistical power of primary studies, and thus, encourage future research on RST.

Cerebral blood flow in essential hypotension during emotional activation

Variations of blood flow velocity in the left and right middle cerebral arteries (MCA) were measured in 20 hypotensive women and 20 normotensive control subjects during emotional stimulation using functional transcranial Doppler sonography (fTDS). The emotional stimuli were composed of three series (neutral, pleasant, and unpleasant) of 20 pictures from the International Affective Picture System (IAPS). Both groups exhibited greater increases in right than left MCA blood flow during emotional stimulation. However hypotensive subjects showed smaller increases in blood flow than did normotensive controls. Furthermore hypotensives exhibited lower MCA blood flow velocity in both hemispheres at rest than did normotensives. Nevertheless the hypotensive group rated the emotional pictures as more arousing than did the control group. Results suggest a decreased blood flow, in addition to peripheral, in the central nervous system (CNS) of hypotensives, which was associated with normal emotional responses for both valence and hemispherical asymmetry, but also with a general increase of arousal levels. This dissociation might be related to an increase in anterior cerebral arteries (ACA) blood flow and/or to hypotension-mediated baroreceptors' up-regulation to the reticular system.

An electrophysiological link between the cerebellum, cognition and emotion: Frontal theta EEG activity to single-pulse cerebellar TMS

Early intracranial electrical stimulation studies in animals demonstrated cerebellar connectivity to brain structures involved in cognitive and emotive functions. Human electrophysiological data to support cerebellum involvement in the latter functions are however lacking. In the present study, electrophysiological responses were recorded to single-pulse transcranial magnetic stimulation (TMS) over the vermis in healthy human volunteers. Increased theta activity was observed after single-pulse vermis TMS as compared to sham and occipital TMS. Both animal and human research relate theta activity with the septo-hippocampal complex, an important brain structure involved in cognition and emotion. The present electrophysiological study supports the earlier intracranial electrical stimulation findings by demonstrating cerebellar involvement in the modulation of the core frequencies related to cognitive and emotive aspects of human behavior.