Neurocognitive mechanisms of anxiety: an integrative account

Cerebral White Matter Changes in Young Healthy Individuals With High Trait Anxiety: A Tract-Based Spatial Statistics Study

Background: Abnormalities in prespecified and empirical white matter tracts in young patients with anxiety-related disorders have been reported in some diffusion tensor imaging (DTI) studies. However, with few literatures examining the association between the integrity of whole brain white matter and trait anxiety levels in the non-clinical populations, whether white matter changes arise in young healthy individuals with high trait anxiety remains unknown.

Methods: We examined whole brain white matter alterations in young healthy individuals with high anxiety but without history of neurological or psychiatric disorders via DTI technology. Group comparison of tract-based spatial statistics (TBSS) was performed to investigate the microstructural diffusion alterations in 38 high anxious subjects in comparison with 34 low anxious subjects matched with age, gender, and degree of education. These analyses controlled for depression to establish specificity to trait anxiety.

Results: Young healthy subjects with high trait anxiety had significantly decreased fractional anisotropy (FA) values in multiple clusters, including corona radiate (CR), anterior thalamic radiation (ATR), inferior fronto-occipital fasciculus (IFOF), bilaterally, body, genu, and splenium of corpus callosum (CC) and forceps minor, compared with low trait anxious subjects. For the abnormal FA regions, the other diffusion metrics were also altered slightly.

Conclusions: Non-clinical individuals with high anxiety already have white matter alterations in the thalamus-cortical circuit and some emotion-related areas that were widely reported in anxiety-related disorders. The altered white matter may be a vulnerability marker in individuals at high risk of clinical anxiety. These findings can deepen our understanding of the pathological mechanism of anxiety and further support the need for preventive interventions in high anxiety individuals.

Effects of heart rate variability biofeedback training in athletes exposed to stress of university examinations

Introduction

Heart rate variability biofeedback (HRV-BFB) training, a method whereby one controls an unusually low breathing rate to reach cardiac coherence, has been shown to reduce anxiety and improve cardiac autonomic markers in diseased people, but much less is known about HRV-BFB benefits in healthy people. Here we investigated potential benefits in young competitors experiencing stress during university examinations as well as persistence of benefits after HRV-BFB training cessation.

Methods

A group of sports students (n = 12) practiced 5-min HRV-BFB training twice a day for 5-weeks using URGOfeel^® (URGOTECH) and was compared to a control group (n = 6). University examinations occurred immediately after HRV-BFB training (Exam1), then 12-weeks later (Exam2). Anxiety markers and cardiac autonomic markers were assessed at baseline, Exam1 and Exam2. Principal Component Analyses (PCA) that combined all these markers were computed at Exam1 and Exam2 to emphasize covariations.

Results

At Exam 1, immediately after HRV-BFB training cessation, the experimental group demonstrated greater autonomic markers but similar states of anxiety when compared to the Control group. Twelve weeks later at Exam2, autonomic markers were greater and anxiety scores were lesser among the experimental group. PCA highlighted covariations only within cardiac autonomic markers at Exam1. Rather, variations in cardiac markers were associated with anxiety markers at Exam2.

Conclusion

Short sessions of HRV-BFB training for a brief period of 5 weeks bring substantial benefits to autonomic markers and anxiety levels in young competitors. Here beneficial effects persisted for 12 weeks. Dissociated profiles of anxiety and cardiac autonomic adaptations shed new light on the role of the amygdala in heart-brain interactions after cardiac coherence training.

Estradiol moderates the relationship between state-trait anxiety and attentional bias to threat in women

Anxiety disorders are characterized by impaired fear extinction and heightened attentional allocation to threatening stimuli. The sex hormones estradiol and progesterone modulate fear extinction in female rats and women; whether these hormones are similarly related to attentional biases to threat has not been examined. In the present study 74 women (53 cycling, 21 using hormonal contraception), and a comparison group of 30 men, completed standard assessments of state-trait anxiety, as well symptoms of depression, anxiety and stress, followed by a computerized assessment of attentional bias, the dot-probe task. Women's endogenous estradiol and progesterone levels were ascertained by a blood sample. No differences in attentional bias were found dependent on sex or hormonal contraceptive use. Estradiol was the only variable measured that was independently positively correlated with attentional bias to threat. Regression analyses revealed a bi-directional relationship between state-trait anxiety, symptoms of anxiety and stress, and attentional bias that was moderated by estradiol, such that a positive relationship was observed amongst women with higher estradiol, and a negative relationship was observed amongst women with lower estradiol. Together, these results indicate that under conditions of anxiety and stress, women may attend to threat differently depending on endogenous estradiol levels, being avoidant when estradiol is lower, and vigilant when estradiol is higher. A more nuanced understanding of the role for attention in anxiety disorders amongst women may be developed by taking hormonal status into consideration.

The optimistic brain: Trait optimism mediates the influence of resting-state brain activity and connectivity on anxiety in late adolescence

As a hot research topic in the field of psychology and psychiatry, trait optimism reflects the tendency to expect positive outcomes in the future. Consistent evidence has demonstrated the role of trait optimism in reducing anxiety among different populations. However, less is known about the neural bases of trait optimism and the underlying mechanisms for how trait optimism protects against anxiety in the healthy brain. In this investigation, we examined these issues in 231 healthy adolescent students by assessing resting-state brain activity (i.e., fractional amplitude of low-frequency fluctuations, fALFF) and connectivity (i.e., resting-state functional connectivity, RSFC). Whole-brain correlation analyses revealed that higher levels of trait optimism were linked with decreased fALFF in the right orbitofrontal cortex (OFC) and increased RSFC between the right OFC and left supplementary motor cortex (SMC). Mediation analyses further showed that trait optimism mediated the influence of the right OFC activity and the OFC-SMC connectivity on anxiety. Our results remained significant even after excluding the impact of head motion, positive and negative affect and depression. Taken together, this study reveals that fALFF and RSFC are functional neural markers of trait optimism and provides a brain-personality-symptom pathway for protection against anxiety in which fALFF and RSFC affect anxiety through trait optimism.

Anterior cingulate activation to implicit threat before and after treatment for pediatric anxiety disorders

BACKGROUND

Research suggests that individuals with anxiety have difficulty ignoring threat distractors when completing tasks with competing stimuli. Studies examining the neural correlates of these emotional processing difficulties in youth anxiety highlight reduced recruitment of regions associated with goal-directed attention, such as the anterior cingulate cortex (ACC). In the current study, we examined neural activation during an emotional conflict task in youth with anxiety disorders before and after treatment.

METHODS

Twenty-five youth (ages 9-19 years) with generalized, separation, and/or social anxiety disorder and 25 healthy controls underwent 2 functional magnetic resonance imaging scans approximately 13 weeks apart. At each scan, participants completed a task in which they matched shapes in the context of emotional distractors (happy and threatening faces). Between scans, anxious youth were treated with the selective serotonin reuptake inhibitor (SSRI) sertraline or cognitive behavior therapy (CBT).

RESULTS

Prior to treatment, anxious youth exhibited reduced activation of the medial prefrontal cortex, encompassing the rostral ACC, when matching shapes in the context of threat distractors relative to healthy controls. Activation in this region increased in anxious youth after treatment, but remained unchanged in the healthy control group. Increases in rostral ACC activation were related to greater reductions in social anxiety and avoidance symptoms following treatment.

CONCLUSIONS

Effective treatments for pediatric anxiety may enhance rostral ACC response during attempts to filter out threat-relevant stimuli. Enhanced recruitment of this region may constitute one manner in which CBT and SSRI treatment reduce youth anxiety symptoms, particularly social anxiety and avoidance.

Evaluating the Effectiveness of a School-Based Cognitive Behavioural Therapy Intervention for Anxiety in Adolescents Diagnosed with Autism Spectrum Disorder

This study evaluated the effectiveness of a school-based Cognitive Behavioural Therapy (CBT) on symptoms of anxiety, social worry and social responsiveness, and indices of attentional control and attentional biases to threat in adolescents diagnosed with Autism Spectrum Disorder. Thirty-five young people (11–14 years; IQ > 70) with ASD and elevated teacher or parent reported anxiety were randomly assigned to 6 sessions of the Exploring Feelings CBT intervention (Attwood in Exploring feelings (anxiety). Future Horizons, Arlington, 2004) (n = 18) or a wait-list control group (n = 17). The intervention (compared to the wait-list control) group showed positive change for parent, teacher and self-reported anxiety symptoms, and more marginal effects of increased teacher-reported social responsiveness. The discussion highlights the potential value and limitations of school-based CBT for young people with ASD.

Stratification of MDD and GAD patients by resting state brain connectivity predicts cognitive bias

Patients with Generalized Anxiety Disorder (GAD) and Major Depressive Disorder (MDD) show between-group comorbidity and symptom overlap, and within-group heterogeneity. Resting state functional connectivity might provide an alternate, biologically informed means by which to stratify patients with GAD or MDD. Resting state functional magnetic resonance imaging data were acquired from 23 adults with GAD, 21 adults with MDD, and 27 healthy adult control participants. We investigated whether within- or between-network connectivity indices from five resting state networks predicted scores on continuous measures of depression and anxiety. Successful predictors were used to stratify participants into two new groups. We examined whether this stratification predicted attentional bias towards threat and whether this varied between patients and controls. Depression scores were linked to elevated connectivity within a limbic network including the amygdala, hippocampus, VMPFC and subgenual ACC. Patients with GAD or MDD with high limbic connectivity showed poorer performance on an attention-to-threat task than patients with low limbic connectivity. No parallel effect was observed for control participants, resulting in an interaction of clinical status by resting state group. Our findings provide initial evidence for the external validity of stratification of MDD and GAD patients by functional connectivity markers. This stratification cuts across diagnostic boundaries and might valuably inform future intervention studies. Our findings also highlight that biomarkers of interest can have different cognitive correlates in individuals with versus without clinically significant symptomatology. This might reflect protective influences leading to resilience in some individuals but not others.

Primary and Secondary Variants of Psychopathy in a Volunteer Sample Are Associated With Different Neurocognitive Mechanisms

BACKGROUND

Recent work has indicated that there at least two distinct subtypes of psychopathy. Primary psychopathy is characterized by low anxiety and thought to result from a genetic predisposition, whereas secondary psychopathy is characterized by high anxiety and thought to develop in response to environmental adversity. Primary psychopathy is robustly associated with reduced neural activation to others' emotions and, in particular, distress. However, it has been proposed that the secondary presentation has different neurocognitive correlates.

METHODS

Primary (n = 50), secondary (n = 100), and comparison (n = 82) groups were drawn from a large volunteer sample (N = 1444) using a quartile-split approach across psychopathic trait (affective-interpersonal) and anxiety measures. Participants performed a widely utilized emotional face processing task during functional magnetic resonance imaging.

RESULTS

The primary group showed reduced amygdala and insula activity in response to fear. The secondary group did not differ from the comparison group in these regions. Instead, the secondary group showed reduced activity compared with the comparison group in other areas, including the superior temporal sulcus/inferior parietal lobe, thalamus, pallidum, and substantia nigra. Both psychopathy groups also showed reduced activity in response to fear in the anterior cingulate cortex. During anger processing, the secondary group exhibited reduced activity in the anterior cingulate cortex compared with the primary group.

CONCLUSIONS

Distinct neural correlates of fear processing characterize individuals with primary and secondary psychopathy. The reduced neural response to fear that characterizes individuals with the primary variant of psychopathic traits is not observed in individuals with the secondary presentation. The neurocognitive mechanisms underpinning secondary psychopathy warrant further systematic investigation.

Emotion and anxiety potentiate the way attention alters visual appearance

The ability to swiftly detect and prioritize the processing of relevant information around us is critical for the way we interact with our environment. Selective attention is a key mechanism that serves this purpose, improving performance in numerous visual tasks. Reflexively attending to sudden information helps detect impeding threat or danger, a possible reason why emotion modulates the way selective attention affects perception. For instance, the sudden appearance of a fearful face potentiates the effects of exogenous (involuntary, stimulus-driven) attention on performance. Internal states such as trait anxiety can also modulate the impact of attention on early visual processing. However, attention does not only improve performance; it also alters the way visual information appears to us, e.g. by enhancing perceived contrast. Here we show that emotion potentiates the effects of exogenous attention on both performance and perceived contrast. Moreover, we found that trait anxiety mediates these effects, with stronger influences of attention and emotion in anxious observers. Finally, changes in performance and appearance correlated with each other, likely reflecting common attentional modulations. Altogether, our findings show that emotion and anxiety interact with selective attention to truly alter how we see.

Tell me what to do: Stress facilitates stimulus-response learning by instruction

Learning by explicit instruction is a highly efficient way to instantaneously learn new behaviors and to overcome potentially harmful learning by trial-and-error. Despite the importance of instructed learning for education, influences on the efficacy of an instruction are currently unknown. Decades of research, however, showed that stress is a powerful modulator of learning and memory, including the acquisition of stimulus-response (S-R) associations. Moreover, brain areas critical for instructed learning are a major target of hormones and neurotransmitters released during stress. Thus, we investigated here whether acute stress affects instructed S-R learning and whether this effect differs for trial-and-error learning. To this end, healthy participants underwent a stressor (Socially Evaluated Cold Pressor Test) or a control manipulation before learning arbitrary S-R associations. For half of the stimuli, participants were explicitly instructed about the correct association, whereas the remaining associations had to be learned by trial-and-error. As expected, the instruction resulted in better performance and enhanced explicit rule knowledge compared to trial-and-error learning. Stress further boosted the beneficial effect of an explicit instruction on learning performance, while leaving trial-and-error learning unchanged. These beneficial effects of stress were directly correlated with the activity of the autonomic nervous system and the concentration of cortisol. Moreover, acute stress could override the detrimental effect of high trait anxiety levels on instructed S-R learning performance. Our findings indicate that acute stress may facilitate learning from instruction, which may represent a highly efficient way to learn how to act, without the necessity of own experience, that helps to save cognitive resources during a stressful encounter.

Enhanced cholinergic-tone during the stress induce a depressive-like state in mice

Major depressive disorder has a heterogeneous etiology, since it arises from the interaction of multiple factors and different pathophysiological mechanisms are involved in the symptomatology. This study aimed to investigate the role of the cholinergic system in the susceptibility to stress and, consequently, in the depression-like behavior. C57BL/6 mice were treated with Physostigmine (PHYS), an acetylcholinesterase (AChE) inhibitor, and were submitted to the social defeat stress. For the behavioral evaluation of the locomotor activity, anxiety-like and depression-like behaviors the open field, elevated plus maze, sucrose preference, social interaction and forced swim were used. Hippocampus and prefrontal cortex samples were collected for evaluation of AChE activity, as well as blood samples for analysis of serum cortisol levels. Our results showed that 15 min after the injection of PHYS there was a significant inhibition of AChE activity in the hippocampus and in the prefrontal cortex. On the other hand, in the end of the experimental design, day 12, there was no difference in AChE activity levels. Inhibition of AChE and exposure to the stress led to an increase in cortisol levels. Animals that received PHYS and were exposed to stress showed less social interaction and greater learned helplessness, anhedonia and anxious-like behavior. Taken together, our findings suggest that increasing the cholinergic tone shortly before stress induction impacts on the ability to cope with upcoming stressful situations, leading to a depressive-like state.

Speech Disfluency-dependent Amygdala Activity in Adults Who Stutter: Neuroimaging of Interpersonal Communication in MRI Scanner Environment

Affective states, such as anticipatory anxiety, critically influence speech communication behavior in adults who stutter. However, there is currently little evidence regarding the involvement of the limbic system in speech disfluency during interpersonal communication. We designed this neuroimaging study and experimental procedure to sample neural activity during interpersonal communication between human participants, and to investigate the relationship between the amygdala activity and speech disfluency. Participants were required to engage in live communication with a stranger of the opposite sex in the MRI scanner environment. In the gaze condition, the stranger gazed at the participant without speaking, while in the live conversation condition, the stranger asked questions that the participant was required to answer. The stranger continued to gaze silently at the participant while the participant answered. Adults who stutter reported significantly higher discomfort than fluent controls during the experiment. Activity in the right amygdala, a key anatomical region in the limbic system involved in emotion, was significantly correlated with stuttering occurrences in adults who stutter. Right amygdala activity from pooled data of all participants also showed a significant correlation with discomfort level during the experiment. Activity in the prefrontal cortex, which forms emotion regulation neural circuitry with the amygdala, was decreased in adults who stutter than in fluent controls. This is the first study to demonstrate that amygdala activity during interpersonal communication is involved in disfluent speech in adults who stutter.

Trajectories of depressive and anxiety symptoms in older adults: a 6-year prospective cohort study

OBJECTIVE

Depressive and anxiety symptoms are common in older adults, significantly affect quality of life, and are risk factors for Alzheimer's disease. We sought to identify the determinants of predominant trajectories of depressive and anxiety symptoms in cognitively normal older adults.

METHOD

Four hundred twenty-three older adults recruited from the general community underwent Aβ positron emission tomography imaging, apolipoprotein and brain-derived neurotrophic factor genotyping, and cognitive testing at baseline and had follow-up assessments. All participants were cognitively normal and free of clinical depression at baseline. Latent growth mixture modeling was used to identify predominant trajectories of subthreshold depressive and anxiety symptoms over 6 years. Binary logistic regression analysis was used to identify baseline predictors of symptomatic depressive and anxiety trajectories.

RESULTS

Latent growth mixture modeling revealed two predominant trajectories of depressive and anxiety symptoms: a chronically elevated trajectory and a low, stable symptom trajectory, with almost one in five participants falling into the elevated trajectory groups. Male sex (relative risk ratio (RRR) = 3.23), lower attentional function (RRR = 1.90), and carriage of the brain-derived neurotrophic factor Val66Met allele in women (RRR = 2.70) were associated with increased risk for chronically elevated depressive symptom trajectory. Carriage of the apolipoprotein epsilon 4 allele (RRR = 1.92) and lower executive function in women (RRR = 1.74) were associated with chronically elevated anxiety symptom trajectory.

CONCLUSION

Our results indicate distinct and sex-specific risk factors linked to depressive and anxiety trajectories, which may help inform risk stratification and management of these symptoms in older adults at risk for Alzheimer's disease. Copyright © 2017 John Wiley & Sons, Ltd.

Delta-beta correlation as a candidate endophenotype of social anxiety: A two-generation family study

BACKGROUND

Social anxiety disorder (SAD) is characterized by an extreme and intense fear and avoidance of social situations. In this two-generation family study we examined delta-beta correlation during a social performance task as candidate endophenotype of SAD.

METHODS

Nine families with a target participant (diagnosed with SAD), their spouse and children, as well as target's siblings with spouse and children performed a social performance task in which they gave a speech in front of a camera. EEG was measured during resting state, anticipation, and recovery. Our analyses focused on two criteria for endophenotypes: co-segregation within families and heritability.

RESULTS

Co-segregation analyses revealed increased negative delta-low beta correlation during anticipation in participants with (sub)clinical SAD compared to participants without (sub)clinical SAD. Heritability analyses revealed that delta-low beta and delta-high beta correlation during anticipation were heritable. Delta-beta correlation did not differ between participants with and without (sub)clinical SAD during resting state or recovery, nor between participants with and without SAD during all phases of the task.

LIMITATIONS

It should be noted that participants were seen only once, they all performed the EEG tasks in the same order, and some participants were too anxious to give a speech.

CONCLUSIONS

Delta-low beta correlation during anticipation of giving a speech might be a candidate endophenotype of SAD, possibly reflecting increased crosstalk between cortical and subcortical regions. If validated as endophenotype, delta-beta correlation during anticipation could be useful in studying the genetic basis, as well as improving treatment and early detection of persons at risk for developing SAD.

Dysfunctional Limbic Circuitry Underlying Freezing of Gait in Parkinson's Disease

Freezing of gait (FOG) is a poorly understood symptom affecting many patients with Parkinson's disease (PD). Despite growing evidence of a behavioral link between anxiety, attention and FOG in PD, no research to date has investigated the neural mechanisms that might explain this relationship. The present study therefore examined resting-state MRI functional connectivity between the amygdala, striatum and frontoparietal attentional control network in PD patients with (freezers: n = 19) and without FOG (non-freezers: n = 21) in the dopaminergic 'off' state. Functional connectivity was subsequently correlated with an objective measure of FOG severity and a subjective scale of affective disorder within each group. Connectivity between the right amygdala and right putamen was significantly increased in freezers compared to non-freezers (p < 0.01). Furthermore, freezers showed increased anti-coupling between the frontoparietal network and left amygdala (p = 0.011), but reduced anti-coupling between this network and the right putamen (p = 0.027) as compared to non-freezers. Key functional connections between the amygdala, putamen and frontoparietal network were significantly associated with FOG severity and a fear of falling. This study provides the first evidence that dysfunctional fronto-striato-limbic processes may underpin the link between anxiety and FOG in PD. It is proposed that freezers have heightened striato-limbic load and reduced top-down attentional control at rest, which when further challenged by the parallel processing demands of walking may precipitate FOG.

Affective Responses to Acute Bouts of Aerobic Exercise, Mindfulness Meditation, and Combinations of Exercise and Meditation: A Randomized Controlled Intervention

Single bouts of aerobic exercise and meditation have been shown to induce positive affect. In a novel experimental paradigm, we sought to examine the effects of an acute bout of aerobic exercise and meditation, as well as exercise and meditation combined on affect among young adults. Participants ( N = 110, mean age = 21.4 years) were randomly assigned to walk, meditate, walk then meditate, meditate then walk, or to sit (inactive control). All walking and meditation bouts were 10 minutes in duration. Participants' affect was monitored before and after the intervention using the Exercise Induced Feelings Inventory. Significant group × time interaction effects were observed for three Exercise Induced Feelings Inventory subscales, including revitalization ( p < .001), tranquility ( p = .02), and exhaustion ( p = .03); the group × time interaction for Exercise Induced Feelings Inventory positive engagement was nonsignificant ( p = .16). A single bout of brisk walking or meditation, as well as a combination of walking and meditation, may positively influence affect. There is some evidence to suggest that affective benefits may be greater following meditation or a combination of meditation and walking, when compared with walking alone.

The role of prefrontal-subcortical circuitry in negative bias in anxiety: Translational, developmental and treatment perspectives

Anxiety disorders are the most common cause of mental ill health in the developed world, but our understanding of symptoms and treatments is not presently grounded in knowledge of the underlying neurobiological mechanisms. In this review, we discuss accumulating work that points to a role for prefrontal-subcortical brain circuitry in driving a core psychological symptom of anxiety disorders - negative affective bias. Specifically, we point to converging work across humans and animal models, suggesting a reciprocal relationship between dorsal and ventral prefrontal-amygdala circuits in promoting and inhibiting negative bias, respectively. We discuss how the developmental trajectory of these circuits may lead to the onset of anxiety during adolescence and, moreover, how effective pharmacological and psychological treatments may serve to shift the balance of activity within this circuitry to ameliorate negative bias symptoms. Together, these findings may bring us closer to a mechanistic, neurobiological understanding of anxiety disorders and their treatment.

Differential Experimental Effects of a Short Bout of Walking, Meditation, or Combination of Walking and Meditation on State Anxiety Among Young Adults

INTRODUCTION

Single bouts of aerobic exercise and meditation have been shown to improve anxiety states. Yet to be evaluated in the literature, we sought to examine the effects of a single, short bout of aerobic exercise or meditation, as well as exercise and meditation combined on state anxiety among young adults.

DESIGN

Randomized controlled trial.

SETTING

University.

SUBJECTS

Participants (N = 110, mean age = 21.4 years) were randomly assigned to walk, meditate, walk then meditate, meditate then walk, or to sit (inactive control).

MEASURES

All walking and meditation bouts were 10 minutes in duration. Participants' state anxiety was monitored before and after the intervention using the State Trait Anxiety Inventory questionnaire.

RESULTS

Significant group × time interaction effects were observed ( P = .01). Post hoc paired t tests revealed that state anxiety significantly decreased from baseline to postintervention in the meditation ( P = .002), meditation then walk ( P = .002), and walk then meditation ( P = .03) groups but not the walk ( P = .75) or control ( P = .45) groups.

CONCLUSION

Meditation (vs a brisk walk) may be a preferred method of attenuating anxiety symptomology. Individuals desiring the health benefits associated with aerobic exercise may achieve additional anxiolytic benefits if they employ a brief meditation session before or after exercising.

Basolateral amygdala-ventromedial prefrontal cortex connectivity predicts cognitive behavioural therapy outcome in adults with obsessive-compulsive disorder

BACKGROUND

Cognitive behavioural therapy (CBT), including exposure and ritual prevention, is a first-line treatment for obsessive-compulsive disorder (OCD), but few reliable predictors of CBT outcome have been identified. Based on research in animal models, we hypothesized that individual differences in basolateral amygdala-ventromedial prefrontal cortex (BLA-vmPFC) communication would predict CBT outcome in patients with OCD.

METHODS

We investigated whether BLA-vmPFC resting-state functional connectivity (rs-fc) predicts CBT outcome in patients with OCD. We assessed BLA-vmPFC rs-fc in patients with OCD on a stable dose of a selective serotonin reuptake inhibitor who then received CBT and in healthy control participants.

RESULTS

We included 73 patients with OCD and 84 healthy controls in our study. Decreased BLA-vmPFC rs-fc predicted a better CBT outcome in patients with OCD and was also detected in those with OCD compared with healthy participants. Additional analyses revealed that decreased BLA-vmPFC rs-fc uniquely characterized the patients with OCD who responded to CBT.

LIMITATIONS

We used a sample of convenience, and all patients were receiving pharmacological treatment for OCD.

CONCLUSION

In this large sample of patients with OCD, BLA-vmPFC functional connectivity predicted CBT outcome. These results suggest that future research should investigate the potential of BLA-vmPFC pathways to inform treatment selection for CBT across patients with OCD and anxiety disorders.

Trait anxiety and probabilistic learning: Behavioral and electrophysiological findings

Anxiety is a negative emotion that affects various aspects of people's daily life. To explain why individuals with high anxiety tend to make suboptimal decisions, we suggest that their learning ability might play an important role. Regarding that anxiety modulates both outcome expectation and attention allocation, it is reasonable to hypothesize that the function of feedback learning should be sensitive to individual level of anxiety. However, previous studies that directly examined this hypothesis were scarce. In this study, forty-two Chinese participants were assigned to a high-trait anxiety (HTA) group or a low-trait anxiety (LTA) group according to their scores in the Trait form of Spielberger's State-Trait Anxiety Inventory (STAI-T). Both groups finished a reward learning task in which two options were associated with different winning probabilities. The event-related potential (ERP) elicited by outcome feedback during the task was recorded and analyzed. Behavioral results revealed that, when the winning probability was 80% for one option and 20% for another, the HTA group chose the 80% winning option less often than the LTA group at the initial stage (i.e., first 20 trials) of the task, but there was no between-group difference in total number of choice. In addition, HTA participants took more time to make decisions in the 80/20 condition than in the 50/50 condition, but this effect was insignificant in the LTA group. ERP results indicated that anxiety affects learning in two ways. First, compared to their LTA counterparts, HTA participants showed a smaller feedback-related negativity (FRN) in response to negative feedback, indicating the impact of anxiety on outcome expectation. Second, HTA participants showed a larger P3 component in the 80/20 condition than in the 50/50 condition, indicating the impact of anxiety on attention allocation. Accordingly, we suggest that individuals' ability of feedback learning could be negatively modulated by anxiety.

Attentional bias mediates the effect of neurostimulation on emotional vulnerability

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique which has garnered recent interest in the potential treatment for emotion-based psychopathology. While accumulating evidence suggests that tDCS may attenuate emotional vulnerability, critically, little is known about underlying mechanisms of this effect. The present study sought to clarify this by examining the possibility that tDCS may affect emotional vulnerability via its capacity to modulate attentional bias towards threatening information. Fifty healthy participants were randomly assigned to receive either anodal tDCS (2 mA/min) stimulation to the left dorsolateral prefrontal cortex (DLPFC), or sham. Participants were then eye tracked during a dual-video stressor task designed to elicit emotional reactivity, while providing a concurrent in-vivo measure of attentional bias. Greater attentional bias towards threatening information was associated with greater emotional reactivity to the stressor task. Furthermore, the active tDCS group showed reduced attentional bias to threat, compared to the sham group. Importantly, attentional bias was found to statistically mediate the effect of tDCS on emotional reactivity, while no direct effect of tDCS on emotional reactivity was observed. The findings are consistent with the notion that the effect of tDCS on emotional vulnerability may be mediated by changes in attentional bias, holding implications for the application of tDCS in emotion-based psychopathology. The findings also highlight the utility of in-vivo eye tracking measures in the examination of the mechanisms associated with DLPFC neuromodulation in emotional vulnerability.

Attentional Control and Fear Extinction in Subclinical Fear: An Exploratory Study

Attentional control (AC) and fear extinction learning are known to be involved in pathological anxiety. In this study we explored whether individual differences in non-emotional AC were associated with individual differences in the magnitude and gradient of fear extinction (learning and recall). In 50 individuals with fear of spiders, we collected measures of non-emotional AC by means of self-report and by assessing the functioning of the major attention networks (executive control, orienting, and alerting). The participants then underwent a paradigm assessing fear extinction learning and extinction recall. The two components of the orienting network functioning (costs and benefits) were significantly associated with fear extinction gradient over and above the effects of trait anxiety. Specifically, participants with enhanced orienting costs (i.e., difficulties in disengaging attention from cues not relevant for the task) showed faster extinction learning, while those with enhanced orienting benefits (i.e., attention facilitated by valid cues) exhibited faster extinction recall as measured by fear-potentiated startle and Unconditioned Stimulus expectancies, respectively. Our findings suggest that, in non-emotional conditions, the orienting component of attention may be predictive of fear extinction. They also show that the use of fear extinction gradients and the exploration of individual differences in non-emotional AC (using performance-based measures of attentional network functioning) can provide a better understanding of individual differences in fear learning. Our findings also may help to understand differences in exposure therapy outcomes.

Putative EEG measures of social anxiety: Comparing frontal alpha asymmetry and delta-beta cross-frequency correlation

The goal of the present study was to examine whether frontal alpha asymmetry and delta-beta cross-frequency correlation during resting state, anticipation, and recovery are electroencephalographic (EEG) measures of social anxiety. For the first time, we jointly examined frontal alpha asymmetry and delta-beta correlation during resting state and during a social performance task in high (HSA) versus low (LSA) socially anxious females. Participants performed a social performance task in which they first watched and evaluated a video of a peer, and then prepared their own speech. They believed that their speech would be videotaped and evaluated by a peer. We found that HSA participants showed significant negative delta-beta correlation as compared to LSA participants during both anticipation of and recovery from the stressful social situation. This negative delta-beta correlation might reflect increased activity in subcortical brain regions and decreased activity in cortical brain regions. As we hypothesized, no group differences in delta-beta correlation were found during the resting state. This could indicate that a certain level of stress is needed to find EEG measures of social anxiety. As for frontal alpha asymmetry, we did not find any group differences. The present frontal alpha asymmetry results are discussed in relation to the evident inconsistencies in the frontal alpha asymmetry literature. Together, our results suggest that delta-beta correlation is a putative EEG measure of social anxiety.

Neurogenetic plasticity and sex influence the link between corticolimbic structural connectivity and trait anxiety

Corticolimbic pathways connecting the amygdala and ventral prefrontal cortex (vPFC) are linked with trait anxiety, but it remains unclear what potential genetic moderators contribute to this association. We sought to address this by examining the inter-individual variability in neuroplasticity as modeled by a functional polymorphism (rs6265) in the human gene for brain derived neurotrophic factor (BDNF). Amygdala-vPFC pathway fractional anisotropy (FA) from 669 diffusion magnetic resonance images was used to examine associations with trait anxiety as a function of rs6265 genotype. We first replicated the inverse correlation between trait anxiety and amygdala-vPFC pathway FA in women. Furthermore, we found a moderating influence of rs6265 genotype such that the association between trait anxiety and right amygdala-vPFC pathway FA was strongest in women carrying the Met allele, which is linked with decreased activity-dependent neuroplasticity. Results indicate that the microstructural integrity of pathways supporting communication between the amygdala and vPFC help shape the expression of trait anxiety in women, and that this association is further modulated by genetically driven variability in neuroplasticity.

Novelty and fear conditioning induced gene expression in high and low states of anxiety

Emotional states influence how stimuli are interpreted. High anxiety states in humans lead to more negative, threatening interpretations of novel information, typically accompanied by activation of the amygdala. We developed a handling protocol that induces long-lasting high and low anxiety-like states in rats to explore the role of state anxiety on brain activation during exposure to a novel environment and fear conditioning. In situ hybridization of the inducible transcription factor Egr-1 found increased gene expression in the lateral nucleus of the amygdala (LA) following exposure to a novel environment and contextual fear conditioning in high anxiety-like rats. In contrast, low state anxiety-like rats did not generate Egr-1 increases in LA when placed in a novel chamber. Egr-1 expression was also examined in the dorsal hippocampus and prefrontal cortex. In CA1 of the hippocampus and medial prefrontal cortex (mPFC), Egr-1 expression increased in response to novel context exposure and fear conditioning, independent of state anxiety level. Furthermore, in mPFC, Egr-1 in low anxiety-like rats was increased more with fear conditioning than novel exposure. The current series of experiments show that brain areas involved in fear and anxiety-like states do not respond uniformly to novelty during high and low states of anxiety.

GABA content within medial prefrontal cortex predicts the variability of fronto-limbic effective connectivity

The amygdala-medial prefrontal cortex (mPFC) circuit plays a key role in social behavior. The amygdala and mPFC are bidirectionally connected, functionally and anatomically, via the uncinate fasciculus. Recent evidence suggests that GABA-ergic neurotransmission within the mPFC could be central to the regulation of amygdala activity related to emotions and anxiety processing. However, the functional and neurochemical interactions within amygdala-mPFC circuits are unclear. In the current study, multimodal magnetic resonance imaging techniques were combined to investigate effective connectivity within the amygdala-mPFC network and its relationship with mPFC neurotransmission in 22 healthy subjects aged between 41 and 88 years. Effective connectivity in the amygdala-mPFC circuit was assessed on resting-state functional magnetic resonance imaging data using spectral dynamic causal modelling. State and trait anxiety were also assessed. The mPFC was shown to be the target of incoming outputs from the amygdalae and the source of exciting inputs to the limbic system. The amygdalae were reciprocally connected by excitatory projections. About half of the variance relating to the strength of top-down endogenous connection between right amygdala and mPFC was explained by mPFC GABA levels. State anxiety was correlated with the strength of the endogenous connections between right amygdala and mPFC. We suggest that mPFC GABA content predicts variability in the effective connectivity within the mPFC-amygdala circuit, providing new insights on emotional physiology and the underlying functional and neurochemical interactions.

Avoiding math on a rapid timescale: Emotional responsivity and anxious attention in math anxiety

Math anxiety (MA) is characterized by negative feelings towards mathematics, resulting in avoidance of math classes and of careers that rely on mathematical skills. Focused on a long timescale, this research may miss important cognitive and affective processes that operate moment-to-moment, changing rapid reactions even when a student simply sees a math problem. Here, using fMRI with an attentional deployment paradigm, we show that MA influences rapid spontaneous emotional and attentional responses to mathematical stimuli upon brief presentation. Critically, participants viewed but did not attempt to solve the problems. Indicating increased threat reactivity to even brief presentations of math problems, increased MA was associated with increased amygdala response during math viewing trials. Functionally and anatomically defined amygdala ROIs yielded similar results, indicating robustness of the finding. Similar to the pattern of vigilance and avoidance observed in specific phobia, behavioral results of the attentional paradigm demonstrated that MA is associated with attentional disengagement for mathematical symbols. This attentional avoidance is specific to math stimuli; when viewing negatively-valenced images, MA is correlated with attentional engagement, similar to other forms of anxiety. These results indicate that even brief exposure to mathematics triggers a neural response related to threat avoidance in highly MA individuals.

The "weakest link" as an indicator of cognitive vulnerability differentially predicts symptom dimensions of anxiety in adolescents in China

This multiwave longitudinal study examined the cognitive vulnerability-stress component of hopelessness theory to differentially predict symptom dimensions of anxiety using a "weakest link" approach in a sample of adolescents from Hunan Province, China. Baseline and 6-month follow-up data were obtained from 553 middle-school students. During an initial assessment, participants completed measures of assessing their weakest links, anxious symptoms, and the occurrence of stress. Participants subsequently completed measures assessing stress, and anxious symptoms one a month for six months. Higher weakest link scores were associated with greater increases in the harm avoidance and separation anxiety/panic dimensions, but not the physical or social anxiety dimension, of anxious symptoms following stress in Chinese adolescents. These results support the applicability of the "weakest link" approach, derived from hopelessness theory, in Chinese adolescents. Weakest link scores as cognitive vulnerability factors may play a role in the development of anxious symptoms, especially in the cognitive dimensions (e.g., harm avoidance and separation anxiety/panic). Our findings also have potential value in explaining the effectiveness of cognitive relevant therapy in treating the cognitive dimensions of anxious symptoms.

Neuroanatomical Substrates of Rodent Social Behavior: The Medial Prefrontal Cortex and Its Projection Patterns

Social behavior encompasses a number of distinctive and complex constructs that form the core elements of human imitative culture, mainly represented as either affiliative or antagonistic interactions with conspecifics. Traditionally considered in the realm of psychology, social behavior research has benefited from recent advancements in neuroscience that have accelerated identification of the neural systems, circuits, causative genes and molecular mechanisms that underlie distinct social cognitive traits. In this review article, I summarize recent findings regarding the neuroanatomical substrates of key social behaviors, focusing on results from experiments conducted in rodent models. In particular, I will review the role of the medial prefrontal cortex (mPFC) and downstream subcortical structures in controlling social behavior, and discuss pertinent future research perspectives.

Effects of task demands on the early neural processing of fearful and happy facial expressions

Task demands shape how we process environmental stimuli but their impact on the early neural processing of facial expressions remains unclear. In a within-subject design, ERPs were recorded to the same fearful, happy and neutral facial expressions presented during a gender discrimination, an explicit emotion discrimination and an oddball detection tasks, the most studied tasks in the field. Using an eye tracker, fixation on the face nose was enforced using a gaze-contingent presentation. Task demands modulated amplitudes from 200 to 350ms at occipito-temporal sites spanning the EPN component. Amplitudes were more negative for fearful than neutral expressions starting on N170 from 150 to 350ms, with a temporo-occipital distribution, whereas no clear effect of happy expressions was seen. Task and emotion effects never interacted in any time window or for the ERP components analyzed (P1, N170, EPN). Thus, whether emotion is explicitly discriminated or irrelevant for the task at hand, neural correlates of fearful and happy facial expressions seem immune to these task demands during the first 350ms of visual processing.

Four Mechanistic Models of Peer Influence on Adolescent Cannabis Use

Purpose of review

Most adolescents begin exploring cannabis in peer contexts, but the neural mechanisms that underlie peer influence on adolescent cannabis use are still unknown. This theoretical overview elucidates the intersecting roles of neural function and peer factors in cannabis use in adolescents.

Recent findings

Novel paradigms using functional magnetic resonance imaging (fMRI) in adolescents have identified distinct neural mechanisms of risk decision-making and incentive processing in peer contexts, centered on reward-motivation and affect regulatory neural networks; these findings inform a theoretical model of peer-driven cannabis use decisions in adolescents.

Summary

We propose four "mechanistic profiles" of social facilitation of cannabis use in adolescents: (1) peer influence as the primary driver of use; (2) cannabis exploration as the primary driver, which may be enhanced in peer contexts; (3) social anxiety; and (4) negative peer experiences. Identification of "neural targets" involved in motivating cannabis use may inform clinicians about which treatment strategies work best in adolescents with cannabis use problems, and via which social and neurocognitive processes.

Neural correlates of explicit and implicit emotion processing in relation to treatment response in pediatric anxiety

BACKGROUND

Approximately 40%-45% of youth with anxiety disorders do not achieve remission (or a substantial reduction in symptoms) following treatment, highlighting the need to identify predictors of treatment response. Given the well-established link between attentional biases and anxiety disorders in youth and adults, this study examined the neural correlates of directing attention toward and away from emotional faces in relation to pediatric anxiety treatment response.

METHOD

Prior to beginning treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline or cognitive behavior therapy (CBT), 37 youth (age 7-19 years) with generalized and/or social anxiety disorder completed a task with conditions that manipulated whether participants were instructed to match emotional faces (explicit emotion processing) or match shapes in the context of emotional face distractors (implicit emotion processing) during functional magnetic resonance imaging.

RESULTS

Results revealed that reduced activation in superior frontal gyrus (SFG), encompassing the dorsal anterior cingulate cortex (ACC) and dorsomedial prefrontal cortex (PFC), during implicit processing of emotional faces predicted a greater reduction in anxiety severity pre-to-post treatment. Post hoc analyses indicated that effects were not significantly moderated by the type of treatment or anxiety type.

CONCLUSIONS

Findings suggest that less recruitment of SFG, including the dorsal ACC and dorsomedial PFC, during implicit emotion processing predicts a greater reduction in youth anxiety symptoms pre-to-post treatment. Youth who exhibit reduced activation in these areas while matching shapes in the context of emotional face distractors may have more to gain from CBT and SSRI treatment due to preexisting deficits in attentional control. These findings suggest that neuroimaging may be a useful tool for predicting which youth are most likely to benefit from anxiety treatment.

Task-dependent modulation of amygdala connectivity in social anxiety disorder

Increased amygdala activation is consistently found in patients suffering from social anxiety disorder (SAD), a psychiatric condition characterized by an intense fear of social situations and scrutiny. Disruptions in the amygdalar-frontal network in SAD may explain the inability of frontal regions to appropriately down-regulate amygdalar hyper-activation. In this study, we measured 15 SAD patients and 15 healthy controls during an affective counting Stroop task with emotional faces to assess the interaction of affective stimuli with a cognitive task in SAD, as well as to investigate the causal interactions between the amygdala and the medial orbitofrontal cortex (OFC) using dynamic causal modeling (DCM). Here we show for the first time that differences in OFC-amygdala effective connectivity between SAD patients and healthy controls are influenced by cognitive load during task processing. In SAD patients relative to controls dysfunctional amygdala regulation was observed during passive viewing of harsh faces This could be linked to ongoing self-initiated cognitive processes (such as rumination and anticipation of negative events) that hinder successful amygdala regulation. However, between-group differences diminished during cognitive processing, suggesting that attentional load interfered with emotional processing in both patients and controls.

Functional and neurochemical interactions within the amygdala-medial prefrontal cortex circuit and their relevance to emotional processing

The amygdala-medial prefrontal cortex (mPFC) circuit plays a key role in emotional processing. GABA-ergic inhibition within the mPFC has been suggested to play a role in the shaping of amygdala activity. However, the functional and neurochemical interactions within the amygdala-mPFC circuits and their relevance to emotional processing remain unclear. To investigate this circuit, we obtained resting-state functional magnetic resonance imaging (rs-fMRI) and proton MR spectroscopy in 21 healthy subjects to assess the potential relationship between GABA levels within mPFC and the amygdala-mPFC functional connectivity. Trait anxiety was assessed using the State-Trait Anxiety Inventory (STAI-Y2). Partial correlations were used to measure the relationships among the functional connectivity outcomes, mPFC GABA levels and STAI-Y2 scores. Age, educational level and amount of the gray and white matters within 1H-MRS volume of interest were included as nuisance variables. The rs-fMRI signals of the amygdala and the vmPFC were significantly anti-correlated. This negative functional coupling between the two regions was inversely correlated with the GABA+/tCr level within the mPFC and the STAI-Y2 scores. We suggest a close relationship between mPFC GABA levels and functional interactions within the amygdala-vmPFC circuit, providing new insights in the physiology of emotion.

Generalized Anxiety Disorder, worry and attention to threat: A systematic review

Among anxious populations, attention has been demonstrated to be preferentially biased to threatening material compared to neutral or other valenced material. Individuals who have high levels of trait worry, such as those with Generalized Anxiety Disorder (GAD), may be biased to threat but research has produced equivocal findings. This review aimed to systematically review the extant experimental literature to establish the current evidence of attentional bias to threat among trait worriers compared to healthy controls and other clinical populations. Twenty-nine published articles were included in the final review. There was strong evidence of a bias to threat among GAD patients compared to other groups and this was found across most experimental paradigms. Few studies had investigated this bias in non-clinical trait worriers. Among GAD patients this bias to threat was most strongly evidenced when visual threat material was in a verbal-linguistic format (i.e., words) rather than when in pictorial form (i.e., images or faces). The bias was also found across several domains of negative material, supporting the general nature of worry. Further research should look to examine the specific components of the threat bias in GAD, as well as investigating the bias to threat in trait worriers.