When Neutral is Not Neutral: Neurophysiological Evidence for Reduced Discrimination between Aversive and Non-Aversive Information in Generalized Anxiety Disorder

Effects of attention bias modification for anxiety: Neurophysiological indices and moderation by symptom severity

OBJECTIVE

Attention bias modification (ABM) aims to decrease anxiety symptom severity through the reduction of threat-related attention bias (AB). Individual differences in treatment response and poor measurement reliability of AB have called its clinical promise into question. The current study examined whether individual differences in anxiety severity at baseline moderated treatment response, and employed both behavioral and neurophysiological metrics of AB.

METHODS

Participants (N = 99) were randomly assigned to four weeks of ABM or placebo control training (PT). Self-reported anxiety symptom severity, and AB metrics and ERPs generated during the dot probe task were collected at baseline (Time 1), one-week post-intervention (Time 5), and at a three-month follow-up (Time 6).

RESULTS

ABM, relative to PT, reduced ERPs indexing attention discrimination (N170) and increased ERPs indexing salience tracking (P3). Increases in P3 were associated with ABM-related reductions in anxiety. Anxiety severity was reduced following ABM, but only among those with higher baseline anxiety symptom severity.

CONCLUSIONS

ABM effectively reduced symptom severity among those with higher levels of anxiety, and modulated neurophysiological indices of AB.

SIGNIFICANCE

Results provide evidence for attention-relevant ERPs as outcomes of ABM treatment responsivity and suggest that ABM may be most beneficial for those with more severe anxiety symptoms.

Early Safety Discrimination Under Uncertainty in Trait Anxiety: An Event-Related Potential Study

Detection of safety-threat signals during uncertainty is an important mechanism of developmental anxiety disorder (AD). Although extensive research has focused on the detection of uncertain threat signals in anxious individuals, relatively little attention has been given to the identification of safety signals during uncertainty, which is an important way to relieve anxiety in individuals with AD. To investigate this phenomenon, 16 subjects with high trait anxiety (HTA) and 16 with low trait anxiety (LTA) completed a modified cue-target task in certain and uncertain stimulus blocks. In the uncertain block, the cue was followed by a threat picture or safety picture in 20% of trials, respectively; in the certain block, the cue could be followed by a threat picture or a safety picture on 100% of trials. Behavioral responses and event-related potentials (ERPs) were recorded. The ERP results demonstrated that LTA participants exhibited larger P2 amplitudes in the detection of safety cues than of threat cues during the uncertain block, whereas HTA participants showed significant P2 amplitudes between the safety and threat cues during the certain block, impairing the detection of safety stimuli during uncertainty. However, all participants exhibited greater N2 amplitudes following threat cues in certainty or uncertainty conditions. These findings pertaining to the P2 amplitude suggested distinctive attentional biases between HTA and LTA individuals, whereas the N2 amplitude showed association learning in uncertain conditions, compensating for safety-threat detection in HTA individuals.

Investigating the consistency of ERPs across threatening situations among children and adolescents

Threat sensitivity is thought to be a precursor for anxiety. Yet it remains unknown whether individuals have consistently high neural activation to different threatening situations. The current study (N = 161, M_age = 11.26, SD = 1.79) used three ERPs from different threat-related events: 1) the P3 to receiving negative feedback; 2) the ERN to making mistakes; 3) the N170 to viewing angry faces. Participants also completed self-report measures of threat sensitivity, impulsivity, and demographics. In a follow-up analysis, we also investigated whether the results replicate when using the difference score for each ERP. Youth with higher self-reported sensitivity to threats and lower self-reported impulsivity had consistently higher neural activation to threatening situations. Males also had consistently higher neural activation to threats compared with females. When using the difference score, we found that youth with higher self-reported threat sensitivity had consistently higher neural activation to threats than nonthreats. Although it is common for youth to have high neural activation during at least one threatening situation (e.g., making mistakes), only ~12% of youth have consistently high neural activation across a variety of different threats. Thus, detecting youth who are sensitive to a variety of different threats may be an important avenue to investigate to identify youth most at risk for the development of anxiety.

Electrophysiological correlates of interference control in the modified emotional Stroop task with emotional stimuli differing in valence, arousal, and subjective significance

The role of emotional factors in maintaining cognitive control is one of the most intriguing issues in understanding emotion-cognition interactions. In the current experiment, we assessed the role of emotional factors (valence, arousal, and subjective significance) in perceptual and conceptual inhibition processes. We operationalised both processes with the classical cognitive paradigms, i.e., the flanker task and the emotional Stroop task merged into a single experimental procedure. The procedure was based on the presentation of emotional words displayed in four different font colours flanked by the same emotional word printed with the same or different font colour. We expected to find distinct effects of both types of interference: earlier for perceptual and later for emotional interference. We also predicted an increased arousal level to disturb inhibitory control effectiveness, while increasing the subjective significance level should improve this process. As we used orthogonal manipulations of emotional factors, our study allowed us for the first time to assess interactions within emotional factors and between types of interference. We found on the behavioural level the main effects of flanker congruency as well as effects of emotionality. On the electrophysiological level, we found effects for EPN, P2, and N450 components of ERPs. The exploratory analysis revealed that effects due to perceptual interference appeared earlier than the effects of emotional interference, but they lasted for an extended period of processing, causing perceptual and emotional interference to partially overlap. Finally, in terms of emotional interference, we showed the effect of subjective significance: the reduction of interference cost in N450 for highly subjective significant stimuli. This study is the first one allowing for the investigation of two different types of interference in a single experiment, and provides insight into the role of emotion in cognitive control.

EEG correlates of attentional control in anxiety disorders: A systematic review of error-related negativity and correct-response negativity findings

BACKGROUND

Anxiety disorders are highly prevalent and cause substantial personal, social and economic burden. Altered attentional control has been shown to be present across anxiety disorders and is associated with specific changes in brain activity which can be recorded by electroencephalogram (EEG). These include changes in the EEG markers of error-related negativity (ERN) and correct-response negativity (CRN), both believed to reflect response monitoring and attentional control pathophysiology in anxiety. The aim of this review was to systematically assess the research on ERN and CRN in attentional control in individuals with clinical anxiety and healthy controls, across emotional and non-emotional attentional control.

METHODS

A comprehensive literature search was conducted for studies published prior to October 22^nd, 2020. Details of the protocol for this systematic review were registered on PROSPERO (CRD42019144885).

RESULTS

66 studies had their data extracted. All 66 studies measured ERN, with 85% finding significantly increased ERN amplitudes associated with clinical anxiety. Only 44 of the extracted studies analysed CRN and only ~20% of these found significant changes in CRN amplitude associated with individuals with clinical anxiety.

LIMITATIONS

There were several anxiety disorders that had either limited literature (i.e. specific phobia, separation anxiety disorder or agoraphobia) or nil literature (i.e. selective mutism) available. No extracted studies included samples of older adults (i.e. aged 60+ years), and only six extracted studies included measures of emotional attentional control.

CONCLUSIONS

Findings indicate the promising utility of ERN of attentional control as a robust, transdiagnostic trait marker of clinical anxiety.

Startle to neutral, not negative stimuli: A neurophysiological correlate of behavioral inhibition in young children

A putative biomarker of anxiety risk, the startle response is typically enhanced by negative compared to neutral emotion modulation in adults, but remains understudied in children. To determine the extent to which neutral, negative, and positively valenced emotional conditions modulate startle response in early life, a child-friendly film paradigm was used to vary emotion across these conditions during startle induction in sixty-four 4- to 7-year-old children. Association of emotion-modulated startle with parent-reported anxiety symptom severity and child behavioral inhibition, a risk factor for anxiety problems, were assessed. Analyses revealed no difference in startle magnitude during negative compared to neutral film clips. By contrast, startle during both negative and neutral conditions was greater than startle during the positive condition. Larger startle magnitude during the neutral condition associated with higher levels of child behavioral inhibition (BI). These results are consistent with possible immaturity of startle response in young children, and suggest that startle amplitude in more emotionally ambiguous, neutral conditions could serve as an early biomarker for anxiety risk.

Absence Makes the Mind Grow Fonder: Reconceptualizing Studies of Safety Learning in Translational Research on Anxiety

Overgeneralized fear (OGF), or indiscriminate fear responses to signals of threat and nonthreat, is a well-studied cognitive mechanism in human anxiety. Anxiety-related OGF has been studied primarily through fear-learning paradigms and conceptualized as overly exaggerated learning of cues signaling imminent threat. However, the role of safety learning in OGF has not only received much less empirical attention but has been fundamentally conceptualized as learning about the absence of threat rather than the presence of safety. As a result, the relative contributions of exaggerated fear learning and weakened safety learning to anxiety-related OGF remain poorly understood, as do the potentially unique biological and behavioral underpinnings of safety learning. The present review outlines these gaps by, first, summarizing animal and human research on safety learning related to anxiety and OGF. Second, we outline innovations in methods to tease apart unique biological and behavioral contributions of safety learning to OGF. Lastly, we describe clinical and treatment implications of this framework for translational research relevant to human anxiety.

Microstructural integrity of affective neurocircuitry in patients with dissociative seizures is associated with emotional task performance, illness severity and trauma history

PURPOSE

To identify variations in white matter tract integrity related to behavioural control in response to emotional stimuli in patients with dissociative seizures (DS) and healthy controls (HC), and examine associations with illness characteristics and psychological trauma history.

METHODS

Twenty DS patients and 20 HC completed an emotional go/no-go task and questionnaires, and then underwent diffusion tensor imaging (DTI).

RESULTS

Patients had higher false alarm rates in response to negative emotional stimuli than HC. Task performance was correlated with self-reported difficulties in emotional awareness and regulation in everyday life. White matter analysis using tract-based spatial statistics revealed no between-group differences. In patients, fractional anisotropy (FA) in the right uncinate fasciculus, right and left fornix/stria terminalis, and corpus callosum were correlated with task performance. Similar results were found for radial diffusivity (RD), but not mean (MD) or axial diffusivity (AD). In HC, task performance was associated with AD and RD of fewer and smaller clusters in the corpus callosum and right fornix/stria terminalis, and none for FA or MD. Probabilistic tractography of thus identified tracts revealed that mean FA values were correlated with illness parameters (right fornix/stria terminalis with age at onset; posterior corpus callosum with seizure frequency), and psychological trauma history (traumatic experiences during adolescence with anterior corpus callosum).

CONCLUSIONS

Patients with DS show impaired behavioural control in response to emotional stimuli. Microstructural variations in task-related neurocircuitry show associations with illness parameters and psychological trauma history. Future studies using psychiatric controls should examine the specificity of these findings.

Progressive brain structural alterations assessed via causal analysis in patients with generalized anxiety disorder

Accumulating neuroimaging studies implicate widespread brain structural alterations in patients with generalized anxiety disorder (GAD), but little is known regarding the temporal information of these changes and their causal relationships. In this study, a morphometric analysis was performed on T1-weighted structural images, and the progressive changes in the gray matter volume (GMV) in GAD were simulated by dividing the patients into different groups from low illness duration to high illness duration. The duration was defined as the interval between the onset of GAD and the time for magnetic resonance imaging collection. Then, a causal structural covariance network analysis was conducted to describe the causal relationships of the brain structural alterations in GAD. With increased illness duration, the GMV reduction in GAD originated from the subgenual anterior cingulate cortex (sgACC) and propagated to the bilateral ventromedial prefrontal cortex, right dorsomedial prefrontal cortex, left inferior temporal gyrus, and right insula. Intriguingly, the sgACC and the right insula had positive causal effects on each other. Moreover, both sgACC and right insula exhibited positive causal effects on the parietal cortex and negative effects on the posterior cingulate cortex, dorsolateral prefrontal cortex, visual cortex, and temporal lobe. The opposite causal effects were noted on the somatosensory and the ventrolateral prefrontal cortices. In conclusion, patients with GAD show gradual GMV reduction with increasing ilness duration. Furthermore, the causal effects of the sgACC and the right insula GMV reduction with shifts of duration may provide an important new avenue for understanding the pathological anomalies in GAD.

Heterogeneity of the Anxiety-Related Attention Bias: A Review and Working Model for Future Research

The anxiety-related attention bias (AB) has been studied for several decades as a clinically-relevant output of the dynamic and complex threat detection-response system. Despite research enthusiasm for the construct of AB, current theories and measurement approaches cannot adequately account for the growing body of mixed, contradictory, and null findings. Drawing on clinical, neuroscience, and animal models, we argue that the apparent complexity and contradictions in the empirical literature can be attributed to the field's failure to clearly conceptualize AB heterogeneity and the dearth of studies in AB that consider additional cognitive mechanisms in anxiety, particularly disruptions in threat-safety discrimination and cognitive control. We review existing research and propose a working model of AB heterogeneity positing that AB may be best conceptualized as multiple subtypes of dysregulated processing of and attention to threat anchored in individual differences in threat-safety discrimination and cognitive control. We review evidence for this working model and discuss how it can be used to advance knowledge of AB mechanisms and inform personalized prevention and intervention approaches.