Neural correlates of the emotional Stroop task in panic disorder patients: an event-related fMRI study

The Effectiveness of a Digital App for Reduction of Clinical Symptoms in Individuals With Panic Disorder: Randomized Controlled Trial

BACKGROUND

Panic disorder is a common and important disease in clinical practice that decreases individual productivity and increases health care use. Treatments comprise medication and cognitive behavioral therapy. However, adverse medication effects and poor treatment compliance mean new therapeutic models are needed.

OBJECTIVE

We hypothesized that digital therapy for panic disorder may improve panic disorder symptoms and that treatment response would be associated with brain activity changes assessed with functional near-infrared spectroscopy (fNIRS).

METHODS

Individuals (n=50) with a history of panic attacks were recruited. Symptoms were assessed before and after the use of an app for panic disorder, which in this study was a smartphone-based app for treating the clinical symptoms of panic disorder, panic symptoms, depressive symptoms, and anxiety. The hemodynamics in the frontal cortex during the resting state were measured via fNIRS. The app had 4 parts: diary, education, quest, and serious games. The study trial was approved by the institutional review board of Chung-Ang University Hospital (1041078-202112-HR-349-01) and written informed consent was obtained from all participants.

RESULTS

The number of participants with improved panic symptoms in the app use group (20/25, 80%) was greater than that in the control group (6/21, 29%; χ21=12.3; P=.005). During treatment, the improvement in the Panic Disorder Severity Scale (PDSS) score in the app use group was greater than that in the control group (F1,44=7.03; P=.01). In the app use group, the total PDSS score declined by 42.5% (mean score 14.3, SD 6.5 at baseline and mean score 7.2, SD 3.6 after the intervention), whereas the PDSS score declined by 14.6% in the control group (mean score 12.4, SD 5.2 at baseline and mean score 9.8, SD 7.9 after the intervention). There were no significant differences in accumulated oxygenated hemoglobin (accHbO2) at baseline between the app use and control groups. During treatment, the reduction in accHbO2 in the right ventrolateral prefrontal cortex (VLPFC; F1,44=8.22; P=.006) and the right orbitofrontal cortex (OFC; F1,44=8.88; P=.005) was greater in the app use than the control group.

CONCLUSIONS

Apps for panic disorder should effectively reduce symptoms and VLPFC and OFC brain activity in patients with panic disorder. The improvement of panic disorder symptoms was positively correlated with decreased VLPFC and OFC brain activity in the resting state.

TRIAL REGISTRATION

Clinical Research Information Service KCT0007280; https://cris.nih.go.kr/cris/search/detailSearch.do?seq=21448.

The impact of pandemic-related stress on attentional bias and anxiety in alexithymia during the COVID-19 pandemic

The COVID-19 pandemic had negative consequences for mental health, yet it is unknown how and to what extent the psychological outcomes of this stressful event are moderated by individual traits. Alexithymia is a risk factor for psychopathology, and thus likely predicted individual differences in resilience or vulnerability to stressful events during the pandemic. This study explored the moderating role of alexithymia in the relationships of pandemic-related stress with anxiety levels and attentional bias. The participants were 103 Taiwanese individuals who completed a survey during the outbreak of the Omicron wave. Additionally, an emotional Stroop task including pandemic-related or neutral stimuli was used to measure attentional bias. Our results demonstrate that pandemic-related stress had a lesser impact on anxiety in individuals with a higher level of alexithymia. Moreover, we found that in individuals with higher exposure to pandemic-related stressors, a higher level of alexithymia indicated less attentional bias toward COVID-19-related information. Thus, it is plausible that individuals with alexithymia tended to avoid pandemic-related information, which could temporarily relieve stressors during the pandemic.

Attentional Processing of Unpleasant Stimuli in Alexithymia

Alexithymia is a multi-faceted personality trait defined by difficulties in identifying and describing emotions and is considered a risk factor for multiple psychiatric disorders. Current alexithymia research debates the type of attention bias involved in the processing of negative emotional information, especially in anxiety-evoking situations that are frequently associated with stress states. Relatedly, this study aims to examine the role of emotional influence on the attentional processing of Taiwanese alexithymic individuals. Using the Chinese version of the Toronto Alexithymia Scale-20 (TAS-20), individuals with high alexithymia (HA: TAS > 60, n = 26; Mage = 23.36) and individuals with low alexithymia (LA: TAS < 39, n = 26; Mage = 25.76) were recruited. Participants performed an emotional counting Stroop task preceded by anxiety-evoking (threatening and aversive pictures) or neutral pictures. Reaction times (RTs) of the emotional Stroop task were compared between HA and LA groups. Our results demonstrate that compared to individuals with LA, individuals with HA show early avoidance tendency (i.e., allocate less attentional resources to anxiety-evoking stimuli), and that negative affect therefore does not interfere with subsequent attention processing during the Stroop task, resulting in faster RT for unpleasant stimuli (Mthreatening = 683.87, Maversive = 685.87) than neutral stimuli (Mneutral = 695.64) (ps < .05). In addition, the attentional bias toward specific types of negative emotion was not differentiated in individuals with HA (p < .05), suggesting that alexithymic individuals' emotion schemas may be underdeveloped in terms of ability to specify exact emotions. This study provides evidence regarding early sensitization to negative stimuli during information processing, consistent with the notion that alexithymia is related to avoidant emotion regulation processes.

Eliciting Implicit Awareness in Alzheimer’s Disease and Mild Cognitive Impairment: A Task-Based Functional MRI Study

Background

Recent models of anosognosia in dementia have suggested the existence of an implicit component of self-awareness about one’s cognitive impairment that may remain preserved and continue to regulate behavioral, affective, and cognitive responses even in people who do not show an explicit awareness of their difficulties. Behavioral studies have used different strategies to demonstrate implicit awareness in patients with anosognosia, but no neuroimaging studies have yet investigated its neural bases.

Methods

Patients with amnestic mild cognitive impairment and dementia due to Alzheimer’s disease underwent functional magnetic resonance imaging (fMRI) during the execution of a color-naming task in which they were presented with neutral, negative, and dementia-related words (Dementia-Related Emotional Stroop).

Results

Twenty-one patients were recruited: 12 were classified as aware and 9 as unaware according to anosognosia scales (based on clinical judgment and patient-caregiver discrepancy). Behavioral results showed that aware patients took the longest time to process dementia-related words, although differences between word types were not significant, limiting interpretation of behavioral results. Imaging results showed that patients with preserved explicit awareness had a small positive differential activation of the posterior cingulate cortex (PCC) for the dementia-related words condition compared to the negative words, suggesting attribution of emotional valence to both conditions. PCC differential activation was instead negative in unaware patients, i.e., lower for dementia-related words relative to negative-words. In addition, the more negative the differential activation, the lower was the Stroop effect measuring implicit awareness.

Conclusion

Posterior cingulate cortex preserved response to dementia-related stimuli may be a marker of preserved implicit self-awareness.

ENIGMA-anxiety working group: Rationale for and organization of large-scale neuroimaging studies of anxiety disorders

Anxiety disorders are highly prevalent and disabling but seem particularly tractable to investigation with translational neuroscience methodologies. Neuroimaging has informed our understanding of the neurobiology of anxiety disorders, but research has been limited by small sample sizes and low statistical power, as well as heterogenous imaging methodology. The ENIGMA-Anxiety Working Group has brought together researchers from around the world, in a harmonized and coordinated effort to address these challenges and generate more robust and reproducible findings. This paper elaborates on the concepts and methods informing the work of the working group to date, and describes the initial approach of the four subgroups studying generalized anxiety disorder, panic disorder, social anxiety disorder, and specific phobia. At present, the ENIGMA-Anxiety database contains information about more than 100 unique samples, from 16 countries and 59 institutes. Future directions include examining additional imaging modalities, integrating imaging and genetic data, and collaborating with other ENIGMA working groups. The ENIGMA consortium creates synergy at the intersection of global mental health and clinical neuroscience, and the ENIGMA-Anxiety Working Group extends the promise of this approach to neuroimaging research on anxiety disorders.

The alterations of degree centrality in the frontal lobe of patients with panic disorder

Objective: The brain network in panic disorder (PD) is still an intriguing issue for research. In this study, we hoped to investigate the role of DC (degree centrality) for the pathophysiology of PD, especially for the fear network. Methods: We enrolled 60 patients with PD and 60 controls in the current study. The gender and age were matched for two groups. All participants received the resting-state functional magnetic resonance imaging to survey the baseline brain activity. Then the DC values of all participants were using REST toolbox. We also compared the DC values between PD and controls. The statistical threshold was set as FDR (false discovery rate) < 0.05. Results: The DC values were significantly lower in the right superior frontal gyrus of PD patients compared to controls (FDR < 0.05). In addition, a negative correlation between the DC values and panic severity was observed in the right superior frontal gyrus and left inferior frontal gyrus. However, there was no significant association between the DC values and illness duration. Conclusion: The DC seemed significantly altered in the frontal lobe of PD patients. The role of the frontal lobe might be more emphasized in the pathophysiology research for PD.

Separate neural networks of implicit emotional processing between pictures and words: A coordinate-based meta-analysis of brain imaging studies

Both pictures and words are frequently employed as experimental stimuli to investigate the neurocognitive mechanisms of emotional processing. However, it remains unclear whether emotional picture processing and emotional word processing share neural underpinnings. To address this issue, we focus on neuroimaging studies examining the implicit processing of affective words and pictures, which require participants to meet cognitive task demands under the implicit influence of emotional pictorial or verbal stimuli. A coordinate-based activation likelihood estimation meta-analysis was conducted on these studies, which revealed no common activation maximum between the picture and word conditions. Specifically, implicit negative picture processing (35 experiments, 393 foci, and 932 subjects) engages the bilateral amygdala, left hippocampus, fusiform gyri, and right insula, which are mainly located in the subcortical network and visual network associated with bottom-up emotional responses. In contrast, implicit negative word processing (34 experiments, 316 foci, and 799 subjects) engages the default mode network and fronto-parietal network including the ventrolateral prefrontal cortex, dorsolateral prefrontal cortex, and dorsomedial prefrontal cortex, indicating the involvement of top-down semantic processing and emotion regulation. Our findings indicate that affective pictures (that intrinsically have an affective valence) and affective words (that inherit the affective valence from their object) modulate implicit emotional processing in different ways, and therefore recruit distinct brain systems.

Neural correlates of negative and disease-specific emotional stimuli in panic disorder: a functional magnetic resonance imaging study

OBJECTIVE

Decades of research have highlighted the involvement of the prefrontal cortex, anterior cingulated cortex, and limbic areas (amygdala) in panic disorder (PD). However, little attention has been given specifically to the inferior frontal gyrus. The current study aimed to investigate the neural substrates, including the inferior frontal gyrus, of both panic-related and negative conditions among individuals with PD and healthy controls.

METHODS

We examined 13 medication-free PD patients and 14 healthy controls with functional magnetic resonance imaging (fMRI) during exposure to negative and neutral pictures and a set of specific panic-related pictures.

RESULTS

Subtraction between the conditions indicated activation of the left amygdala region and the right inferior frontal gyrus in PD patients during the specific panic-related condition, whereas the left amygdalar region and left inferior frontal gyrus were activated during the negative condition in controls.

CONCLUSION

These results suggest that in patients with PD, a prominent bottom-up process is involved in specific panic-related conditions, which might be associated with weak modulation of the left frontal area. These data add to our current understanding of the neural correlates of PD and can contribute to future clinical interventions targeting the functional reestablishment of these regions.

Dysfunctional frontal activation of mismatch negativity in panic disorder: A magnetoencephalographic study

BACKGROUND

Mismatch negativity (MMN) or its magnetic counterpart (MMNm) is a neurophysiological signal to reflect the automatic change-detection ability. However, MMN studies in patients with panic disorder (PD) showed contrasting results using electroencephalographic (EEG) recordings. The present study attempted to overcome the limitations of EEG methodology by means of a whole-head magnetoencephalography (MEG) combined with the depth-weighted minimum norm estimate method to conduct an in-depth investigation on the MMNm at the cortical level in patients with PD.

METHODS

We recruited 22 healthy controls (HC) and 20 patients with PD to perform auditory oddball paradigm during MEG recordings. The cortical MMNm amplitudes and latencies in the superior temporal gyrus, inferior parietal lobule, and inferior frontal gyrus (IFG) were compared between the HC and PD groups. The correlations between MMNm responses and clinical measurement were also examined.

RESULTS

Compared with the HC group, the PD group demonstrated significantly reduced MMNm amplitudes in the IFG. Furthermore, higher trait scores of the State-Trait Anxiety Inventory were associated with lower MMNm amplitudes of the right IFG among patients with PD.

LIMITATIONS

Generalization of the current results to other settings or samples should be made cautiously due to the use of different medication regimens and presence of comorbidities in our patients.

CONCLUSIONS

Our data suggest dysfunctional pre-attentive change-detection ability in patients with PD, particularly in the IFG.

Biomarkers in Panic Disorder

Background:

Panic disorder (PD) is a kind of anxiety disorder that impacts the life quality and functional perspectives in patients. However, the pathophysiological study of PD seems still inadequate and many unresolved issues need to be clarified.

Objectives:

In this review article of biomarkers in PD, the investigator will focus on the findings of magnetic resonance imaging (MRI) of the brain in the pathophysiology study. The MRI biomarkers would be divided into several categories, on the basis of structural and functional perspectives.

Methods:

The structural category would include the gray matter and white matter tract studies. The functional category would consist of functional MRI (fMRI), resting-state fMRI (Rs-fMRI), and magnetic resonance spectroscopy (MRS). The PD biomarkers revealed by the above methodologies would be discussed in this article.

Results:

For the gray matter perspectives, the PD patients would have alterations in the volumes of fear network structures, such as the amygdala, parahippocampal gyrus, thalamus, anterior cingulate cortex, insula, and frontal regions. For the white matter tract studies, the PD patients seemed to have alterations in the fasciculus linking the fear network regions, such as the anterior thalamic radiation, uncinate fasciculus, fronto-occipital fasciculus, and superior longitudinal fasciculus. For the fMRI studies in PD, the significant results also focused on the fear network regions, such as the amygdala, hippocampus, thalamus, insula, and frontal regions. For the Rs-fMRI studies, PD patients seemed to have alterations in the regions of the default mode network and fear network model. At last, the MRS results showed alterations in neuron metabolites of the hippocampus, amygdala, occipital cortex, and frontal regions.

Conclusion:

The MRI biomarkers in PD might be compatible with the extended fear network model hypothesis in PD, which included the amygdala, hippocampus, thalamus, insula, frontal regions, and sensory-related cortex.

Attempted induction of signalled lucid dreaming by transcranial alternating current stimulation

Neurophysiological correlates of self-awareness during sleep ('lucid dreaming') remain unclear despite their importance for clarifying the neural underpinnings of consciousness. Transcranial direct (tDC) and alternating (tAC) current stimulation during sleep have been shown to increase dream self-awareness, but these studies' methodological weaknesses prompted us to undertake additional study. tAC stimulation was associated with signal-verified and self-rated lucid dreams-but so was the sham procedure. Situational factors may be crucial to inducing self-awareness during sleep.

Frontal brain activity in individuals at risk for schizophrenic psychosis and bipolar disorder during the emotional Stroop task - an fNIRS study

OBJECTIVES

The emotional Stroop effect is defined as increased reaction times to emotional stimuli compared to neutral ones. It has been often reported in the literature, on both behavioral and neurophysiological level. The goal of this study was to investigate the frontal brain activation in individuals at risk for schizophrenic psychosis and bipolar disorder during an emotional Stroop task. We expected to observe decreased activation in the at-risk individuals compared to the healthy controls.

METHODS

Individuals at high risk for psychosis (HR), at ultra-high risk for psychosis (UHR), at risk for bipolar disorder (BIP) and healthy controls (HC) performed an emotional Stroop task, which included positively, negatively and neutrally valenced words. Functional near-infrared spectroscopy (fNIRS) was used to measure levels of oxygenated hemoglobin (O2Hb) representing brain activity in the dorsolateral prefrontal and frontotemporal cortex.

RESULTS

Results showed significantly decreased levels of O2Hb in the right dorsolateral prefrontal cortex (DLPFC) in the HR and UHR groups compared to the HC, indicating lower activity. Even though the decrease was independent from the valence of the words, it was the most visible for the negative ones. Moreover, significantly lower O2Hb levels in the frontotemporal cortex (FTC) were observed in all at risk groups compared to the HC.

CONCLUSIONS

Lower activity in the FTC in groups at risk for psychosis and bipolar disorder reflects unspecific dysfunctions. Decreased activity in the DLPFC in the HR and UHR groups indicates that hypofrontality can be found already in individuals at risk for schizophrenic psychosis.

Task MRI-Based Functional Brain Network of Anxiety

Magnetic resonance imaging (MRI) is a good tool for researchers to understand the biological mechanisms and pathophysiology of the brain due to the translational characteristics of MRI methods. For the psychiatric illness, this kind of mental disorders usually have minor alterations when compared to traditional neurological disorders. Therefore the functional study, such as functional connectivity, would play a significant role for understanding the pathophysiology of mental disorders. This chapter would focus on the discussion of task MRI-based functional network studies in anxiety. For social anxiety disorder, the limbic system, such as the temporal lobe, amygdala, and hippocampus, would show alterations in the functional connectivity with frontal regions, such as anterior cingulate, prefrontal, and orbitofrontal cortices. PD has anterior cingulate cortex-amygdala alterations in fear conditioning, frontoparietal alterations in attention network task, and limbic-prefrontal alterations in emotional task. A similar amygdala-based aberrant functional connectivity in specific phobia is observed. The mesocorticolimbic and limbic-prefrontal functional alterations are found in generalized anxiety disorder. The major components of task MRI-based functional connectivity in anxiety include limbic and frontal regions which might play a vital role for the origination of anxiety under different scenarios and tasks.

Threat-of-shock decreases emotional interference on affective stroop performance in healthy controls and anxiety patients

Patients with anxiety disorders suffer from impaired concentration, potentially as a result of stronger emotional interference on attention. Studies using behavioural measures provide conflicting support for this hypothesis. Elevated state anxiety may be necessary to reliably document differences in emotional interference in patients versus healthy controls. The present study examines the effect of experimentally induced state anxiety (threat-of-shock) on attention interference by emotional stimuli. Anxiety patients (n = 36) and healthy controls (n = 32) completed a modified affective Stroop task during periods of safety and threat-of-shock. Results indicated that in both patients and controls, threat decreased negative, but not positive or neutral, emotional interference on attention (both p < .001). This finding supports a threat-related narrowing of attention whereby a certain level of anxiety decreases task-irrelevant processing.

Meta-Analysis of Neuropsychological Studies in Panic Disorder Patients: Evidence of Impaired Performance during the Emotional Stroop Task

BACKGROUND

Recent investigations have highlighted significant differences in verbal recall between patients with panic disorder (PD) and controls. These studies have highlighted that verbal memory and working memory could be impaired in PD.

OBJECTIVES

The objective of the present meta-analysis is to confirm this hypothesis, reviewing the studies that have investigated neurocognitive testing in PD.

METHODS

We performed a systematic literature search for studies published between 1980 and 2015 that reported cognitive measurements in PD patients and controls. Effect size estimates were computed using the restricted maximum likelihood model. Only case-control studies were selected for this meta-analysis. We included studies that made a direct comparison between PD subjects and healthy controls. The diagnostic group consisted of adult patients aged over 18 years diagnosed with PD. We excluded the studies that did not employ a case-control design. All statistical analyses were carried out on R using the "metafor" package version 1.9-8. The effect size for each study neuropsychological test was calculated using the mean and SD of performance results, and p values < 0.05 were considered significant.

RESULTS

We identified few studies that tested verbal memory and executive functions in PD patients and controls, and this difference was not significant. On the other hand, there are several studies that have used the emotional Stroop task to assess cognitive functions in PD. There is no robust evidence of impairment of memory function in PD; however, when considering the emotional Stroop task, it was found that PD patients performed slower (p < 0.01) than healthy controls for all three types of stimuli (neutral, negative, positive).

CONCLUSION

This meta-analysis included a small number of studies, which may have introduced bias into the analysis. However, there is some evidence of impairment of neurocognitive functions in PD when performing the emotional Stroop task. Furthermore, the paucity of studies evaluating neurocognition in PD suggests the need for further research in this field in order to draw meaningful conclusions.

Sack A, Fecteau S. Characterizing emotional Stroop interference in posttraumatic stress disorder, major depression and anxiety disorders: A systematic review and meta-analysis

BACKGROUND

Posttraumatic stress disorder is a debilitating psychiatric disorder characterized by symptoms of intrusive re-experiencing of trauma, avoidance and hyper-arousal. Diagnosis and treatment of PTSD is further complicated by concurrently occurring disorders, the most frequent being major depressive disorder and anxiety disorders. Previous research highlights that attentional processing in posttraumatic stress disorder is associated with substantial interference by emotional stimuli, a phenomenon also observed in these concurrently occurring psychiatric disorders. However, the diagnosis-relevance of this interference remains elusive. Here, we investigated the emotional Stroop interference for diagnosis-related stimuli, generally negative stimuli, and generally positive stimuli in posttraumatic stress disorder, major depressive disorder and anxiety disorders.

METHODS

We performed a systematic database search in PubMed (Medline), Cochrane Library and PsycINFO on emotional Stroop performance in individuals with a diagnosis of posttraumatic stress disorder, major depressive disorder or anxiety disorders separately. Mean effect sizes, standard errors and confidence intervals were estimated for each clinical group and healthy control group comparison using random effect models.

RESULTS

As compared to healthy control group, the posttraumatic stress disorder group displayed greater interference by diagnosis-related stimuli and positive stimuli but not for generally negative stimuli. The major depressive disorder and anxiety disorders groups showed greater interference by diagnosis-related and negative stimuli, but not by positive stimuli. The age and sex had no significant impact on interference.

CONCLUSIONS

These findings highlight the importance of diagnosis-relevant information on attentional processing in all three clinical populations, posttraumatic stress disorder, major depressive disorder and anxiety disorders. Further, the impact of generally negative stimuli but not generally positive stimuli in major depressive disorder and anxiety disorders indicate impaired attentional bias for mood-congruent stimuli but not for general stimuli. Finally, it remains to be studied whether the influence of generally positive stimuli in posttraumatic stress disorder indicate that positive stimuli are perceived as PTSD related.

Neuro-hemodynamic endophenotypes of emotional interference in OCD: fMRI study using emotion counting stroop task

BACKGROUND

We sought to examine the endophenotype pattern of neuro-hemodynamic substrates of emotion counting Stroop (ecStroop) paradigm in patients with OCD, their unaffected siblings [first degree relatives-FDR] and healthy controls (HC).

METHODS

OCD patients (medication naïve)[N = 16], their unaffected siblings(FDR)[N = 16] and HC [N = 24] were compared using an established ecStroop paradigm in a 3-Tesla fMRI. The relative BOLD signals corresponding to the three types of conditions (neural words-N, words with negative emotional salience-E and words with salience for OCD-O) were examined in the apriori hypothesized brain regions.

RESULTS

Both in O minus N contrast and O minus E contrast, the groups demonstrated significant differential activation of right insula (BA 13). The post-hoc analyses showed in patients and FDRs relative to HC the following: significant hyperactivation of insula in O minus E contrast; significant hyperactivation of right insula and right DLPFC (BA 9) in O minus N contrast.

CONCLUSIONS

The neuro-hemodynamic responses corresponding to the obsessive words in insula and DLPFC could be potential endophenotypes. "Threat relatedness" might thus have a vulnerability meaning in the pathogenesis and neurobiological basis of OCD.

ERP Evidence for Inhibitory Control Deficits in Test-Anxious Individuals

Introduction: Individuals with test anxiety [i.e., high test anxiety (HTA)] always treat tests/examinations as a potential threat. This cognitive mode impairs these individuals' ability of inhibitory control and leads to a high level of anxiety. However, characterizing aspects of HTA's impaired inhibitory control ability are unclear and need to be studied. Methods: Forty-six participants were recruited and divided into a HTA (N = 26) and low test anxiety (LTA; i.e., healthy control; N = 20) group. Self-reports (Test Anxiety Scale, State-Trait Anxiety Inventory for negative emotions) were obtained. An emotional Stroop (ES) task and a numerical Stroop (NS) task, causing different types of interferences, were used for assessing the emotional and cognitive aspects of attentional control ability (behavioral data). Event-related brain potentials (ERPs) were registered to further assess processing stages related to different aspects of attentional control ability. Results: Compared with the LTA group, the HTA group has inhibitory control deficits of both emotional (see ERP components P1-P2-N2 and P3) and cognitive (see ERP component P3) interference. Compared with the LTA group, the HTA doesn't have lower accuracy in neither ES nor NS but displays longer reaction times only in ES. Additionally, the HTA group's ES results also show that (1) the degree of emotional interference indicates the level of an individual's anxiety, and (2) the ERP component P2 may serve as an index of the level of test anxiety. Conclusion: HTA individuals have extensive inhibitory deficits for both emotional and cognitive aspects; however, impairment impacts more on emotional aspects than on cognitive aspects. Additionally, as compared to NS, the negative impact of more impaired processing stages on task performance is more substantial in ES.

Cardiorespiratory concerns shape brain responses during automatic panic-related scene processing in patients with panic disorder

BACKGROUND

Increased automatic processing of threat-related stimuli has been proposed as a key element in panic disorder. Little is known about the neural basis of automatic processing, in particular to task-irrelevant, panic-related, ecologically valid stimuli, or about the association between brain activation and symptomatology in patients with panic disorder.

METHODS

The present event-related functional MRI (fMRI) study compared brain responses to task-irrelevant, panic-related and neutral visual stimuli in medication-free patients with panic disorder and healthy controls. Panic-related and neutral scenes were presented while participants performed a spatially nonoverlapping bar orientation task. Correlation analyses investigated the association between brain responses and panic-related aspects of symptomatology, measured using the Anxiety Sensitivity Index (ASI).

RESULTS

We included 26 patients with panic disorder and 26 heatlhy controls in our analysis. Compared with controls, patients with panic disorder showed elevated activation in the amygdala, brainstem, thalamus, insula, anterior cingulate cortex and midcingulate cortex in response to panic-related versus neutral task-irrelevant stimuli. Furthermore, fear of cardiovascular symptoms (a subcomponent of the ASI) was associated with insula activation, whereas fear of respiratory symptoms was associated with brainstem hyperactivation in patients with panic disorder.

LIMITATIONS

The additional implementation of measures of autonomic activation, such as pupil diameter, heart rate, or electrodermal activity, would have been informative during the fMRI scan as well as during the rating procedure.

CONCLUSION

Results reveal a neural network involved in the processing of panic-related distractor stimuli in patients with panic disorder and suggest an automatic weighting of panic-related information depending on the magnitude of cardiovascular and respiratory symptoms. Insula and brainstem activations show function-related associations with specific components of panic symptomatology.

Imaging and Genetic Approaches to Inform Biomarkers for Anxiety Disorders, Obsessive-Compulsive Disorders, and PSTD

Anxiety disorders are the most common mental health problem in the world and also claim the highest health care cost among various neuropsychiatric disorders. Anxiety disorders have a chronic and recurrent course and cause significantly negative impacts on patients' social, personal, and occupational functioning as well as quality of life. Despite their high prevalence rates, anxiety disorders have often been under-diagnosed or misdiagnosed, and consequently under-treated. Even with the correct diagnosis, anxiety disorders are known to be difficult to treat successfully. In order to implement better strategies in diagnosis, prognosis, treatment decision, and early prevention for anxiety disorders, tremendous efforts have been put into studies using genetic and neuroimaging techniques to advance our understandings of the underlying biological mechanisms. In addition to anxiety disorders including panic disorder, generalised anxiety disorder (GAD), specific phobias, social anxiety disorders (SAD), due to overlapping symptom dimensions, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD) (which were removed from the anxiety disorder category in DSM-5 to become separate categories) are also included for review of relevant genetic and neuroimaging findings. Although the number of genetic or neuroimaging studies focusing on anxiety disorders is relatively small compare to other psychiatric disorders such as psychotic disorders or mood disorders, various structural abnormalities in the grey or white matter, functional alterations of activity during resting-state or task conditions, molecular changes of neurotransmitter receptors or transporters, and genetic associations have all been reported. With continuing effort, further genetic and neuroimaging research may potentially lead to clinically useful biomarkers for the prevention, diagnosis, and management of these disorders.

Neurobiological and clinical effects of fNIRS-controlled rTMS in patients with panic disorder/agoraphobia during cognitive-behavioural therapy

BACKGROUND

A relevant proportion of patients with panic disorder (PD) does not improve even though they receive state of the art treatment for anxiety disorders such as cognitive-behavioural therapy (CBT). At the same time, it is known, that from a neurobiological point of view, PD patients are often characterised by prefrontal hypoactivation. Intermittent Theta Burst Stimulation (iTBS) is a non-invasive type of neurostimulation which can modulate cortical activity and thus has the potential to normalise prefrontal hypoactivity found in PD. We therefore aimed at investigating the effects of iTBS as an innovative add-on to CBT in the treatment for PD.

METHODS

In this double-blind, bicentric study, 44 PD patients, randomised to sham or verum stimulation, received 15 sessions of iTBS over the left prefrontal cortex (PFC) in addition to 9 weeks of group CBT. Cortical activity during a cognitive as well as an emotional (Emotional Stroop) paradigm was assessed both at baseline and post-iTBS treatment using functional near-infrared spectroscopy (fNIRS) and compared to healthy controls.

RESULTS

In this manuscript we only report the results of the emotional paradigm; for the results of the cognitive paradigm please refer to Deppermann et al. (2014). During the Emotional Stroop test, PD patients showed significantly reduced activation to panic-related compared to neutral stimuli for the left PFC at baseline. Bilateral prefrontal activation for panic-related stimuli significantly increased after verum iTBS only. Clinical ratings significantly improved during CBT and remained stable at follow-up. However, no clinical differences between the verum- and sham-stimulated group were identified, except for a more stable reduction of agoraphobic avoidance during follow-up in the verum iTBS group.

LIMITATIONS

Limitations include insufficient blinding, the missing control for possible state-dependent iTBS effects, and the timing of iTBS application during CBT.

CONCLUSION

Prefrontal hypoactivity in PD patients was normalised by add-on iTBS. Clinical improvement of anxiety symptoms was not affected by iTBS.

Veterans with post-traumatic stress disorder exhibit altered emotional processing and attentional control during an emotional Stroop task

BACKGROUND

Post-traumatic stress disorder (PTSD) is often associated with attention allocation and emotional regulation difficulties, but the brain dynamics underlying these deficits are unknown. The emotional Stroop task (EST) is an ideal means to monitor these difficulties, because participants are asked to attend to non-emotional aspects of the stimuli. In this study, we used magnetoencephalography (MEG) and the EST to monitor attention allocation and emotional regulation during the processing of emotionally charged stimuli in combat veterans with and without PTSD.

METHOD

A total of 31 veterans with PTSD and 20 without PTSD performed the EST during MEG. Three categories of stimuli were used, including combat-related, generally threatening and neutral words. MEG data were imaged in the time-frequency domain and the network dynamics were probed for differences in processing threatening and non-threatening words.

RESULTS

Behaviorally, veterans with PTSD were significantly slower in responding to combat-related relative to neutral and generally threatening words. Veterans without PTSD exhibited no significant differences in responding to the three different word types. Neurophysiologically, we found a significant three-way interaction between group, word type and time period across multiple brain regions. Follow-up testing indicated stronger theta-frequency (4-8 Hz) responses in the right ventral prefrontal (0.4-0.8 s) and superior temporal cortices (0.6-0.8 s) of veterans without PTSD compared with those with PTSD during the processing of combat-related words.

CONCLUSIONS

Our data indicated that veterans with PTSD exhibited deficits in attention allocation and emotional regulation when processing trauma cues, while those without PTSD were able to regulate emotion by directing attention away from threat.

Altered Function of Ventrolateral Prefrontal Cortex in Adolescents with Peer Verbal Abuse History

OBJECTIVE

Previous studies showing the association of exposure to peer (PeVA) and parental verbal abuse in childhood with structural alterations in the young adult brain suggest functional changes in adolescence. In this functional MRI study, we investigated the effects of exposure to PeVA, during elementary and middle school periods, on brain response to emotional words, in high school students.

METHODS

An emotional Stroop task consisting of swear, negative, positive, and neutral words was performed during functional MRI scan for 23 subjects who were divided into low- and high exposure groups to PeVA.

RESULTS

High-PeVA group had a higher depression score, greater left ventrolateral prefrontal cortex (VLPFC) activity, and higher left VLPFC-left hippocampus connectivity in swear word conditions. The VLPFC activity and left VLPFC-left hippocampus connectivity was negatively related to the severity of anxiety and depressive symptoms, respectively.

CONCLUSION

These preliminary findings support the hypothesis that exposure to PeVA, during childhood, is an aversive stimulus associated with meaningful functional change in emotional regulation network, showing hypersensitivity to swear words, at middle adolescence.

Functional neuroanatomy in panic disorder: Status quo of the research

AIM

To provide an overview of the current research in the functional neuroanatomy of panic disorder.

METHODS

Panic disorder (PD) is a frequent psychiatric disease. Gorman et al (1989; 2000) proposed a comprehensive neuroanatomical model of PD, which suggested that fear- and anxiety-related responses are mediated by a so-called “fear network” which is centered in the amygdala and includes the hippocampus, thalamus, hypothalamus, periaqueductal gray region, locus coeruleus and other brainstem sites. We performed a systematic search by the electronic database PubMed. Thereby, the main focus was laid on recent neurofunctional, neurostructural, and neurochemical studies (from the period between January 2012 and April 2016). Within this frame, special attention was given to the emerging field of imaging genetics.

RESULTS

We noted that many neuroimaging studies have reinforced the role of the “fear network” regions in the pathophysiology of panic disorder. However, recent functional studies suggest abnormal activation mainly in an extended fear network comprising brainstem, anterior and midcingulate cortex (ACC and MCC), insula, and lateral as well as medial parts of the prefrontal cortex. Interestingly, differences in the amygdala activation were not as consistently reported as one would predict from the hypothesis of Gorman et al (2000). Indeed, amygdala hyperactivation seems to strongly depend on stimuli and experimental paradigms, sample heterogeneity and size, as well as on limitations of neuroimaging techniques. Advanced neurochemical studies have substantiated the major role of serotonergic, noradrenergic and glutamatergic neurotransmission in the pathophysiology of PD. However, alterations of GABAergic function in PD are still a matter of debate and also their specificity remains questionable. A promising new research approach is “imaging genetics”. Imaging genetic studies are designed to evaluate the impact of genetic variations (polymorphisms) on cerebral function in regions critical for PD. Most recently, imaging genetic studies have not only confirmed the importance of serotonergic and noradrenergic transmission in the etiology of PD but also indicated the significance of neuropeptide S receptor, CRH receptor, human TransMEMbrane protein (TMEM123D), and amiloride-sensitive cation channel 2 (ACCN2) genes.

CONCLUSION

In light of these findings it is conceivable that in the near future this research will lead to the development of clinically useful tools like predictive biomarkers or novel treatment options.

The Neurobiology of Panic: A Chronic Stress Disorder

Panic disorder is an often chronic and impairing human anxiety syndrome, which frequently results in serious psychiatric and medical comorbidities. Although, to date, there have been many advances in the diagnosis and treatment of panic disorder, its pathophysiology still remains to be elucidated. In this review, recent evidence for a neurobiological basis of panic disorder is reviewed with particular attention to risk factors such as genetic vulnerability, chronic stress, and temperament. In addition, neuroimaging data are reviewed which provides support for the concept of panic disorder as a fear network disorder. The potential impact of the National Institute of Mental Health Research Domain Criteria constructs of acute and chronic threats responses and their implications for the neurobiology of panic disorder are also discussed.

Brain responses to disorder-related visual threat in panic disorder

Panic disorder (PD) patients show aberrant neural responses to threatening stimuli in an extended fear network, but results are only partially comparable, and studies implementing disorder-related visual scenes are lacking as stimuli. The neural responses and functional connectivity to a newly developed set of disorder-related, ecologically valid scenes as compared with matched neutral visual scenes, using event-related functional magnetic resonance imaging (fMRI) in 26 PD patients and 26 healthy controls (HC) were investigated. PD patients versus HC showed hyperactivation in an extended fear network comprising brainstem, insula, thalamus, anterior, and mid-cingulate cortex and (dorso-)medial prefrontal cortex for disorder-related versus neutral scenes. Amygdala differences between groups failed significance. Subjective levels of anxiety significantly correlated with brainstem activation in PD patients. Analysis of functional connectivity by means of beta series correlation revealed no emotion-specific alterations in connectivity in PD patients versus HC. The results suggest that subjective anxiety evoked by external stimuli is directly related to altered activation in the homeostatic alarm system in PD. With novel disorder-related stimuli, the study sheds new light on the neural underpinnings of pathological threat processing in PD. Hum Brain Mapp 37:4439-4453, 2016. © 2016 Wiley Periodicals, Inc.

Distribution of Response Time, Cortical, and Cardiac Correlates during Emotional Interference in Persons with Subclinical Psychotic Symptoms

A psychosis phenotype can be observed below the threshold of clinical detection. The study aimed to investigate whether subclinical psychotic symptoms are associated with deficits in controlling emotional interference, and whether cortical brain and cardiac correlates of these deficits can be detected using functional near-infrared spectroscopy (fNIRS). A data set derived from a community sample was obtained from the Zurich Program for Sustainable Development of Mental Health Services. 174 subjects (mean age 29.67 ± 6.41, 91 females) were assigned to four groups ranging from low to high levels of subclinical psychotic symptoms (derived from the Symptom Checklist-90-R). Emotional interference was assessed using the emotional Stroop task comprising neutral, positive, and negative conditions. Statistical distributional methods based on delta plots [behavioral response time (RT) data] and quantile analysis (fNIRS data) were applied to evaluate the emotional interference effects. Results showed that both interference effects and disorder-specific (i.e., group-specific) effects could be detected, based on behavioral RTs, cortical hemodynamic signals (brain correlates), and heart rate variability (cardiac correlates). Subjects with high compared to low subclinical psychotic symptoms revealed significantly reduced amplitudes in dorsolateral prefrontal cortices (interference effect, p < 0.001) and middle temporal gyrus (disorder-specific group effect, p < 0.001), supported by behavioral and heart rate results. The present findings indicate that distributional analyses methods can support the detection of emotional interference effects in the emotional Stroop. The results suggested that subjects with high subclinical psychosis exhibit enhanced emotional interference effects. Based on these observations, subclinical psychosis may therefore prove to represent a valid extension of the clinical psychosis phenotype.

Biological markers for anxiety disorders, OCD and PTSD - a consensus statement. Part I: Neuroimaging and genetics

OBJECTIVES

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part I) summarises findings on potential biomarkers in neuroimaging studies, including structural brain morphology, functional magnetic resonance imaging and techniques for measuring metabolic changes, including positron emission tomography and others. Furthermore, this review reports on the clinical and molecular genetic findings of family, twin, linkage, association and genome-wide association studies. Part II of the review focuses on neurochemistry, neurophysiology and neurocognition.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high-quality research has accumulated that will improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Neural correlates of individual differences in anxiety sensitivity: an fMRI study using semantic priming

Individuals with high anxiety sensitivity (AS) have an increased risk of developing anxiety disorders and are more biased in how they process fear-related stimuli. This study investigates the neural correlates of fear-related words and word associations in high- and low-AS individuals. We used a semantic priming paradigm during functional magnetic resonance imaging in which three types of target words (fear symptoms, e.g. 'dizziness'; neutral, e.g. 'drink'; and pseudowords, e.g. 'salkom') were preceded by two types of prime words (fear-triggers, e.g. 'elevator'; and neutral, e.g. 'bottle'). Subjects with high AS rated fear-symptom words (vs neutral words) as more unpleasant than low-AS individuals; they also related these words more strongly to fear-triggers and showed prolonged reaction times. During the processing of fear-symptom words, greater activation in the left anterior insula was observed in high-AS subjects than in low-AS subjects. Lower activation in the left inferior frontal gyrus, angular gyrus, fusiform gyrus and bilateral amygdalae was found in high-AS subjects when fear-symptom words were preceded by fear-trigger words. The findings suggest that cognitive biases and the anterior insula play a crucial role in high-AS individuals. Furthermore, semantic processes may contribute to high AS and the risk of developing anxiety disorders.

Attentional bias in high math-anxious individuals: evidence from an emotional Stroop task

Attentional bias toward threatening or emotional information is considered a cognitive marker of anxiety, and it has been described in various clinical and subclinical populations. This study used an emotional Stroop task to investigate whether math anxiety is characterized by an attentional bias toward math-related words. Two previous studies failed to observe such an effect in math-anxious individuals, although the authors acknowledged certain methodological limitations that the present study seeks to avoid. Twenty high math-anxious (HMA) and 20 low math-anxious (LMA) individuals were presented with an emotional Stroop task including math-related and neutral words. Participants in the two groups did not differ in trait anxiety or depression. We found that the HMA group showed slower response times to math-related words than to neutral words, as well as a greater attentional bias (math-related – neutral difference score) than the LMA one, which constitutes the first demonstration of an attentional bias toward math-related words in HMA individuals.

Frontal cortex absolute beta power measurement in Panic Disorder with Agoraphobia patients

Panic disorder patients are hypervigilant to danger cues and highly sensitive to unpredictable aversive events, what leads to anticipatory anxiety, that is one key component of the disorder maintenance. Prefrontal cortex seems to be involved in these processes and beta band activity may be related to the involvement of top-down processing, whose function is supposed to be disrupted in pathological anxiety. The objective of this study was to measure frontal absolute beta-power (ABP) with qEEG in panic disorder and agoraphobia (PDA) patients compared to healthy controls.

METHODS

qEEG data were acquired while participants (24 PDA patients and 21 controls) watched a computer simulation (CS), consisting of moments classified as "high anxiety" (HAM) and "low anxiety" (LAM). qEEG data were also acquired during two rest conditions, before and after the computer simulation display. The statistical analysis was performed by means of a repeated measure analysis of variance (two-way ANOVA) and ABP was the dependent variable of interest. The main hypothesis was that a higher ABP in PDA patients would be found related to controls. Moreover, in HAM the ABP would be different than in LAM.

RESULTS

the main finding was an interaction between the moment and group for the electrodes F7, F8, Fp1 and Fp2. We observed a higher ABP in PDA patients when compared to controls while watching the CS. The higher beta-power in the frontal cortex for the PDA group may reflect a state of high excitability, together with anticipatory anxiety and maintenance of hypervigilant cognitive state.

CONCLUSIONS

our results suggest a possible deficiency in top-down processing reflected by a higher ABP in the PDA group while watching the CS and they highlight the recruitment of prefrontal regions during the exposure to anxiogenic stimuli.

LIMITATIONS

the small sample, the wide age range of participants and the use of psychotropic medications by most of the PDA patients.

They are laughing at me: cerebral mediation of cognitive biases in social anxiety

The fear of embarrassment and humiliation is the central element of social anxiety. This frequent condition is associated with cognitive biases indicating increased sensitivity to signals of social threat, which are assumed to play a causal role in the maintenance of social anxiety. Here, we employed laughter, a potent medium for the expression of acceptance and rejection, as an experimental stimulus in participants selected for varying degrees of social anxiety to identify cerebral mediators of cognitive biases in social anxiety using functional magnetic resonance imaging in combination with mediation analysis. We directly demonstrated that cerebral activation patterns within the dorsal attention network including the left dorsolateral and dorsomedial prefrontal cortex mediate the influence of social anxiety on laughter perception. This mediation proved to be specific for social anxiety after correction for measures of general state and trait anxiety and occurred most prominently under bimodal audiovisual laughter presentation when compared with monomodal auditory or visual laughter cues. Considering the possibility to modulate cognitive biases and cerebral activity by neuropsychological trainings, non-invasive electrophysiological stimulation and psychotherapy, this study represents a starting point for a whole line of translational research projects and identifies promising targets for electrophysiological interventions aiming to alleviate cognitive biases and symptom severity in social anxiety.

An fMRI-study on semantic priming of panic-related information in depression without comorbid anxiety

Depression often involves anxiety symptoms and shows a strong comorbidity with panic disorder. However, the neural basis is unclear. The aim of the current study was to use semantic priming to investigate the neural correlates of panic and anxiety-related information processing in depression. In a lexical decision task, panic/agoraphobia-disorder-related and neutral word-pairs were presented during functional magnetic resonance imaging. Participants comprised 19 patients with major depression but without comorbid anxiety and 19 demographically matched controls. On a behavioral level, comparable significant priming effects were found for the neutral condition, while only patients showed a significant inhibition effect (slower reaction time for panic-related stimuli) for the panic condition. On a neural level, significant group differences emerged in left fronto-parietal (enhanced activation for patients) and left temporo-occipital regions (reduced activation for patients). The results showed that depressed patients recruit not only areas related to the interaction of emotion and semantic processing but also regions that are related to fear circuitry to process panic-related information. Hence, in the context of depression, there seems to be a pathological processing of panic-related information that could play an important role during the disorder and should be considered.

Frontal white matter alterations in short-term medicated panic disorder patients without comorbid conditions: a diffusion tensor imaging study

The frontal cortex might play an important role in the fear network, and white matter (WM) integrity could be related to the pathophysiology of panic disorder (PD). A few studies have investigated alterations of WM integrity in PD. The aim of this study was to determine frontal WM integrity differences between patients with PD without comorbid conditions and healthy control (HC) subjects by using diffusion tensor imaging. Thirty-six patients with PD who had used medication within 1 week and 27 age- and sex-matched HC subjects participated in this study. Structural brain magnetic resonance imaging was performed on all participants. Panic Disorder Severity Scale and Beck Anxiety Inventory (BAI) scores were assessed. Tract-based spatial statistics (TBSS) was used for image analysis. TBSS analysis showed decreased fractional anisotropy (FA) in frontal WM and WM around the frontal lobe, including the corpus callosum of both hemispheres, in patients with PD compared to HC subjects. Moreover, voxel-wise correlation analysis revealed that the BAI scores for patients with PD were positively correlated with their FA values for regions showing group differences in the FA of frontal WM of both hemispheres. Altered integrity in frontal WM of patients with PD without comorbid conditions might represent the structural pathophysiology in these patients, and these changes could be related to clinical symptoms of PD.

Does rTMS alter neurocognitive functioning in patients with panic disorder/agoraphobia? An fNIRS-based investigation of prefrontal activation during a cognitive task and its modulation via sham-controlled rTMS

OBJECTIVES

Neurobiologically, panic disorder (PD) is supposed to be characterised by cerebral hypofrontality. Via functional near-infrared spectroscopy (fNIRS), we investigated whether prefrontal hypoactivity during cognitive tasks in PD-patients compared to healthy controls (HC) could be replicated. As intermittent theta burst stimulation (iTBS) modulates cortical activity, we furthermore investigated its ability to normalise prefrontal activation.

METHODS

Forty-four PD-patients, randomised to sham or verum group, received 15 iTBS-sessions above the left dorsolateral prefrontal cortex (DLPFC) in addition to psychoeducation. Before first and after last iTBS-treatment, cortical activity during a verbal fluency task was assessed via fNIRS and compared to the results of 23 HC.

RESULTS

At baseline, PD-patients showed hypofrontality including the DLPFC, which differed significantly from activation patterns of HC. However, verum iTBS did not augment prefrontal fNIRS activation. Solely after sham iTBS, a significant increase of measured fNIRS activation in the left inferior frontal gyrus (IFG) during the phonological task was found.

CONCLUSION

Our results support findings that PD is characterised by prefrontal hypoactivation during cognitive performance. However, verum iTBS as an "add-on" to psychoeducation did not augment prefrontal activity. Instead we only found increased fNIRS activation in the left IFG after sham iTBS application. Possible reasons including task-related psychophysiological arousal are discussed.

Advances in the neuroimaging of panic disorder

Models of the neuroanatomy of panic disorder (PD) have relied on both animal work on fear and on clinical data from neuroimaging. Early work hypothesised a network of brain regions involved in fear processing (e.g. the amygdala), but more recent work has also pointed to the involvement of other cortical areas and other brain circuitry (e.g. the insula and anterior cingulate cortex). Studies investigating functional and structural brain connectivity in PD may ultimately shed light on the extent to which the neuroanatomy of PD is localised versus distributed, and on how current treatments alter this neuroanatomy.