Neurocognitive mechanisms of anxiety: an integrative account

The effects of left DLPFC tDCS on emotion regulation, biased attention, and emotional reactivity to negative content

The potentiation of neural activity in lateral prefrontal regions via transcranial direct current stimulation (tDCS) can reduce patterns of biased attention for threat and may facilitate intentional emotion regulation. The current study sought to determine whether left dorsolateral prefrontal cortex tDCS, in combination with intentional down-regulation of emotional responses would reduce negative appraisals of aversive content during emotional regulation (assessed during online tDCS), reduce patterns of biased attention and attention bias variability (assessed offline), and attenuate spontaneous (uninstructed) emotional reactivity to negative content (assessed offline) above tDCS or intentional down-regulation of emotions in isolation. Healthy participants (n = 116) were allocated to one of four experimental conditions involving either active or sham tDCS, combined with an either a down-regulate or maintain emotion regulation task. Attention bias/bias variability was assessed with an attentional probe task, and emotional reactivity was assessed in a negative video viewing task. tDCS did not affect the appraisals of negative stimuli during emotion regulation, and there were no effects on attention bias/bias variability. However, tDCS did attenuate emotional reactivity. Those receiving active stimulation showed smaller elevations in negative mood in response to viewing aversive video content compared with sham. The present findings are consistent with the potential of left frontal tDCS to attenuate negative emotional reactions to aversive content but provide no support for tDCS enhancement of emotion regulation, nor its impact on attention bias or attention bias variability.

Interplay between state anxiety, heart rate variability, and cognition: An ex-Gaussian analysis of response times

The present study employed an ex-Gaussian model of response times (RTs) to elucidate the cognitive processes related to experimentally induced state anxiety (SA) and vagally mediated heart rate variability (vmHRV), an indicator of adaptive responses in both cognitive and affective domains. Participants (n = 110) completed a dual task composed of (i) a flanker attention and (2) working memory load task, while SA was induced by threat of noise. Electrocardiography was measured during the dual task and during four baseline periods in order to calculate vmHRV. RTs on the flanker task were fit to an ex-Gaussian distribution, which estimated three RT parameters: mu (Gaussian mean), sigma (Gaussian SD), and tau (combination of exponential mean and SD). First, findings indicate that threat of noise was associated with reductions in mu and tau, suggesting that SA might improve attention and motor responding. Second, higher resting vmHRV was associated with lower tau (averaged across conditions) and stronger threat-related decreases in tau. Third, intra-individual decreases in vmHRV were accompanied by concomitant decreases in tau. These findings support roles for trait and state vagal control in guiding adaptive anxiety-related (and anxiety-unrelated) attentional responses. Findings are consistent with extant theories that emphasize functional interrelations among emotion, cognition, and vagal function.

Current status of the anger superiority hypothesis: A meta-analytic review of N2pc studies

Numerous investigators have tested contentions that angry faces capture early attention more completely than happy faces do in the context of other faces. However, syntheses of studies on early event-related potentials related to the anger superiority hypothesis have yet to be conducted, particularly in relation to the N200 posterior-contralateral (N2pc) component which provides a reliable electrophysiological index related to orienting of attention suitable for testing this hypothesis. Fifteen samples (N = 534) from 13 studies featuring the assessment of N2pc amplitudes during exposure to angry-neutral and/or happy-neutral facial expression arrays were included for meta-analysis. Moderating effects of study design features and sample characteristics on effect size variability were also assessed. N2pc amplitudes elicited by affectively valenced expressions (angry and happy) were significantly more pronounced than those elicited by neutral expressions. However, the mean effect size difference between angry and happy expressions was ns. N2pc effect sizes were moderated by sample age, number of trials, and nature of facial images used (schematic vs. real) with larger effect sizes observed when samples were comparatively younger, more task trials were presented and schematic face arrays were used. N2pc results did not support anger superiority hypothesis. Instead, attentional resources allocated to angry versus happy facial expressions were similar in early stages of processing. As such, possible adaptive advantages of biases in orienting toward both anger and happy expressions warrant consideration in revisions of related theory.

State anxiety biases estimates of uncertainty and impairs reward learning in volatile environments

Clinical and subclinical (trait) anxiety impairs decision making and interferes with learning. Less understood are the effects of temporary anxious states on learning and decision making in healthy populations, and whether these can serve as a model for clinical anxiety. Here we test whether anxious states in healthy individuals elicit a pattern of aberrant behavioural, neural, and physiological responses comparable with those found in anxiety disorders-particularly when processing uncertainty in unstable environments. In our study, both a state anxious and a control group learned probabilistic stimulus-outcome mappings in a volatile task environment while we recorded their electrophysiological (EEG) signals. By using a hierarchical Bayesian model of inference and learning, we assessed the effect of state anxiety on Bayesian belief updating with a focus on uncertainty estimates. State anxiety was associated with an underestimation of environmental uncertainty, and informational uncertainty about the reward tendency. Anxious individuals' beliefs about reward contingencies were more precise (had smaller uncertainty) and thus more resistant to updating, ultimately leading to impaired reward-based learning. State anxiety was also associated with greater uncertainty about volatility. We interpret this pattern as evidence that state anxious individuals are less tolerant to informational uncertainty about the contingencies governing their environment and more willing to be uncertain about the level of stability of the world itself. Further, we tracked the neural representation of belief update signals in the trial-by-trial EEG amplitudes. In control participants, lower-level precision-weighted prediction errors (pwPEs) about reward tendencies were represented in the ERP signals across central and parietal electrodes peaking at 496 ms, overlapping with the late P300 in classical ERP analysis. The state anxiety group did not exhibit a significant representation of low-level pwPEs, and there were no significant differences between the groups. Smaller variance in low-level pwPE about reward tendencies in state anxiety could partially account for the null results. Expanding previous computational work on trait anxiety, our findings establish that temporary anxious states in healthy individuals impair reward-based learning in volatile environments, primarily through changes in uncertainty estimates, which play a central role in current Bayesian accounts of perceptual inference and learning.

State anxiety reduces working memory capacity but does not impact filtering cost for neutral distracters

Current theories propose that anxiety adversely impacts working memory (WM) by restricting WM capacity and interfering with efficient filtering of task-irrelevant information. The current study investigated the effect of shock-induced state anxiety on WM capacity and the ability to filter task-irrelevant neutral stimuli. We measured the contralateral delay activity (CDA), an event-related potential that indexes the number of items maintained in WM, while participants completed a lateralized change detection task. The task included low and high WM loads, as well as a low load plus distracter condition. This design was used to assess WM capacity for low and high loads and investigate an individual's ability to filter neutral task-irrelevant stimuli. Participants completed the task under two conditions, threat of shock and safe. We observed a reduced CDA in the threat compared to the safe condition that was specific for high memory load. However, we did not find any differences in CDA filtering cost between threat and safe conditions. In addition, we did not find any differences in behavioral performance between the threat and safe conditions. These findings suggest that being in an anxious state reduces the neural representation for large amounts of information in WM, but have little effect on the filtering of neutral distracters.

Salient safety conditioning improves novel discrimination learning

Generalized fear is one purported mechanism of anxiety that is a target of clinical and basic research. Impaired fear discrimination has been primarily examined from the perspective of increased fear learning, rather than how learning about non-threatening stimuli affects fear discrimination. To address this question, we tested how three Safety Conditioning protocols with varied levels of salience allocated to the safety cue compared to classic Fear Conditioning in their impact on subsequent innate anxiety, and differential fear learning of new aversive and neutral cues. Using a high anxiety strain of mice (129SvEv, Taconic), we show that Fear Conditioned animals show little exploration of the anxiogenic center of an open field 24 h later, and poor discrimination during new differential conditioning 7 days later. Three groups of mice underwent Safety Conditioning, (i) the safety tone was unpaired with a shock, (ii) the safety tone was unpaired with the shock and co-terminated with a house light signaling the end of the safety period, and (iii) the safety tone was unpaired with the shock and its beginning co-occurred with a house light, signaling the start of a safety period. Mice from all Safety Conditioning groups showed higher levels of open field exploration than the Fear Conditioned mice 24 h after training. Furthermore, Safety Conditioned animals showed improved discrimination learning of a novel non-threat, with the Salient Beginning safety conditioned group performing best. These findings indicate that high anxiety animals benefit from salient safety training to improve exploration and discrimination of new non-threating stimuli.

Recent advances with 5-HT3 modulators for neuropsychiatric and gastrointestinal disorders

Serotonin (5-hydroxytryptophan [5-HT]) is a biologically active amine expressed in platelets, in gastrointestinal (GI) cells and, to a lesser extent, in the central nervous system (CNS). This biogenic compound acts through the activation of seven 5-HT receptors (5-HT_1-7 Rs). The 5-HT₃ R is a ligand-gated ion channel belonging to the Cys-loop receptor family. There is a wide variety of 5-HT₃ R modulators, but only receptor antagonists (known as setrons) have been used clinically for chemotherapy-induced nausea and vomiting and irritable bowel syndrome treatment. However, since the discovery of the setrons in the mid-1980s, a large number of studies have been published exploring new potential applications due their potency in the CNS and mild side effects. The results of these studies have revealed new potential applications, including the treatment of neuropsychiatric disorders such as schizophrenia, depression, anxiety, and drug abuse. In this review, we provide information related to therapeutic potential of 5-HT₃ R antagonists on GI and neuropsychiatric disorders. The major attention is paid to the structure, function, and pharmacology of novel 5-HT₃ R modulators developed over the past 10 years.

Impacts of trait anxiety on visual working memory, as a function of task demand and situational stress

Higher trait anxiety can impair cognitive functioning via attention, but relatively little is known about the impacts on visual working memory. These were investigated using previously validated visual feature binding tasks. In Study 1, participants' memory for visual features (shapes) and feature bindings (coloured shapes) was assessed. Stimulus presentation was simultaneous or sequential, varying attentional demand, and participants were grouped according to trait cognitive anxiety (low, moderate, high). No reliable effect of trait anxiety, either cognitive or somatic, was found on memory accuracy, but moderate trait cognitive anxiety was associated with faster correct response times (i.e. increased efficiency) when stimuli were sequentially presented. In Study 2, the role of situational stress was explored during a simultaneously presented task. Higher trait cognitive and somatic anxiety were both associated with poorer efficiency during both shape and binding memory tasks. Trait somatic anxiety also predicted poorer binding effectiveness (i.e. accuracy), in those reporting higher state cognitive anxiety. Situational stress predicted binding effectiveness, but never interacted with trait anxiety, and was therefore not necessary to observe these trait anxiety-visual working memory relationships. Trait cognitive and somatic anxiety, and situational stress, therefore each influence visual working memory performance.

Attentional bias towards negative stimuli in healthy individuals and the effects of trait anxiety

This study aimed to investigate the time course of attentional bias for negative information in healthy individuals and to assess the associated influence of trait anxiety. Thirty-eight healthy volunteers performed an emotional dot-probe task with pairs of negative and neutral scenes, presented for either 1 or 2 s and followed by a target placed at the previous location of either negative or neutral stimulus. Analyses included eye movements during the presentation of the scenes and response times associated with target localization. In a second step, analyses focused on the influence of trait anxiety. While there was no significant difference at the behavioral level, the eye-tracking data revealed that negative information held longer attention than neutral stimuli once fixated. This initial maintenance bias towards negative pictures then increased with increasing trait anxiety. However, at later processing stages, only individuals with the highest trait anxiety appeared to fixate longer on negative pictures than neutral pictures, individuals with low trait anxiety showing the opposite pattern. This study provides novel evidence that healthy individuals display an attentional maintenance bias towards negative stimuli, which is associated with trait anxiety.

Does anxiety impact the neural processing of child faces in mothers of school-aged children? An ERP study using an emotional Go/NoGo task

Maternal anxiety during pregnancy and the early postpartum period is associated with heightened neural processing of neutral infant faces as measured by event-related potentials (ERPs). However, less is known about how anxiety shapes neural face processing in mothers of older children. In our study, 36 mothers of 8-10 year old children completed a Go/NoGo task consisting of neutral and emotional (happy, fearful) facial expressions posed by unfamiliar school-aged children while EEG was recorded. Higher levels of maternal anxiety -indexed via self-report- were associated with delayed behavioral responses to children's fearful faces and increased N170 and LPP amplitudes elicited by children's neutral faces. While anxiety was also positively related to the LPP elicited by children's emotional faces, it only led to increased N170 amplitude responses to children's fearful, but not happy, faces and only when they were NoGo cues. The study replicates and extends prior findings examining the impact of maternal anxiety on neural responses to neutral infant faces to later stages of parenting with further neural markers and emotional expressions being affected. Findings evidence the importance of studying these associations beyond infancy to increase our knowledge about processes potentially underlying the relation between anxiety and less optimal parenting across development.

Executive functioning, adaptive skills, emotional and behavioral profile: A comparison between autism spectrum disorder and phenylketonuria

INTRODUCTION

Influential theories maintain that some of Autism Spectrum Disorder (ASD) core symptoms may arise from deficits in executive functions (EF). EF deficits are also considered a neuropsychological marker of early treated individuals with phenylketonuria (PKU). Aims of this study were: to verify the occurrence and patterns of specific EF impairments in both clinical groups; to explore the coexistence of EF alterations with adaptive, behavioral and emotional problems in each clinical condition.

MATERIAL AND METHODS

We assessed EF, adaptive, behavioral and emotional profile in 21 participants with ASD, 15 early treated PKU individuals, comparable for age and IQ, and 14 controls, comparable for age to the clinical groups (age range: 7-14 years).

RESULTS

ASD and PKU participants presented two different, but partially overlapping patterns of EF impairment. While ASD participants showed a specific deficit in cognitive flexibility only, PKU individuals showed a more extensive impairment in EF with a weaker performance in two core EF domains (inhibition, cognitive flexibility) as compared to healthy controls. Psychological and adaptive profile was typical in PKU participants, while ASD participants experienced behavioral (externalizing symptoms), emotional (internalizing symptoms) and adaptive disorders (general, practical, social domains).

CONCLUSIONS

Present results support the view of a relative disengagement of adaptive and emotional-behavioral profile with respect to EF skills and suggest that other dysfunctions contribute to the multidimensional phenotype of ASD participants.

Amygdala-prefrontal connectivity modulates loss aversion bias in anxious individuals

Anxious individuals tend to make pessimistic judgments in decision making under uncertainty. While this phenomenon is commonly attributed to risk aversion, loss aversion is a critical but often overlooked factor. In this study, we simultaneously examined risk aversion and loss aversion during decision making in high and low trait anxious individuals in a variable gain/loss gambling task during functional magnetic resonance imaging. Although high relative to low anxious individuals showed significant increased risk aversive behavior reflected by decreased overall gamble decisions, there was no group difference in subjective aversion to risk. Instead, loss aversion rather than risk aversion dominantly contributed to predict behavioral decisions, which was associated with attenuated functional connectivity between the amygdala-based emotional system and the prefrontal control regions. Our findings suggest a dominant role of loss aversion in maladaptive risk assessment of anxious individuals, underpinned by disorganization of emotion-related and cognitive-control-related brain networks.

Alterations in the amplitude and burst rate of beta oscillations impair reward-dependent motor learning in anxiety

Anxiety results in sub-optimal motor learning, but the precise mechanisms through which this effect occurs remain unknown. Using a motor sequence learning paradigm with separate phases for initial exploration and reward-based learning, we show that anxiety states in humans impair learning by attenuating the update of reward estimates. Further, when such estimates are perceived as unstable over time (volatility), anxiety constrains adaptive behavioral changes. Neurally, anxiety during initial exploration increased the amplitude and the rate of long bursts of sensorimotor and prefrontal beta oscillations (13-30 Hz). These changes extended to the subsequent learning phase, where phasic increases in beta power and burst rate following reward feedback were linked to smaller updates in reward estimates, with a higher anxiety-related increase explaining the attenuated belief updating. These data suggest that state anxiety alters the dynamics of beta oscillations during reward processing, thereby impairing proper updating of motor predictions when learning in unstable environments.

Review of EEG, ERP, and Brain Connectivity Estimators as Predictive Biomarkers of Social Anxiety Disorder

Social anxiety disorder (SAD) is characterized by a fear of negative evaluation, negative self-belief and extreme avoidance of social situations. These recurrent symptoms are thought to maintain the severity and substantial impairment in social and cognitive thoughts. SAD is associated with a disruption in neuronal networks implicated in emotional regulation, perceptual stimulus functions, and emotion processing, suggesting a network system to delineate the electrocortical endophenotypes of SAD. This paper seeks to provide a comprehensive review of the most frequently studied electroencephalographic (EEG) spectral coupling, event-related potential (ERP), visual-event potential (VEP), and other connectivity estimators in social anxiety during rest, anticipation, stimulus processing, and recovery states. A search on Web of Science provided 97 studies that document electrocortical biomarkers and relevant constructs pertaining to individuals with SAD. This study aims to identify SAD neuronal biomarkers and provide insight into the differences in these biomarkers based on EEG, ERPs, VEP, and brain connectivity networks in SAD patients and healthy controls (HC). Furthermore, we proposed recommendations to improve methods of delineating the electrocortical endophenotypes of SAD, e.g., a fusion of EEG with other modalities such as functional magnetic resonance imaging (fMRI) and magnetoencephalograms (MEG), to realize better effectiveness than EEG alone, in order to ultimately evolve the treatment selection process, and to review the possibility of using electrocortical measures in the early diagnosis and endophenotype examination of SAD.

Trait Anxiety Mediated by Amygdala Serotonin Transporter in the Common Marmoset

High trait anxiety is associated with altered activity across emotion regulation circuitry and a higher risk of developing anxiety disorders and depression. This circuitry is extensively modulated by serotonin. Here, to understand why some people may be more vulnerable to developing affective disorders, we investigated whether serotonin-related gene expression across the brain's emotion regulation circuitry may underlie individual differences in trait anxiety using the common marmoset (Callithrix jacchus, mixed sexes) as a model. First, we assessed the association of region-specific expression of the serotonin transporter (SLC6A4) and serotonin receptor (HTR1A, HTR2A, HTR2C) genes with anxiety-like behavior; and second, we investigated their causal role in two key features of the high trait anxious phenotype: high responsivity to anxiety-provoking stimuli and an exaggerated conditioned threat response. While the expression of the serotonin receptors did not show a significant relationship with anxiety-like behavior in any of the targeted brain regions, serotonin transporter expression, specifically within the right ventrolateral prefrontal cortex (vlPFC) and most strongly in the right amygdala, was associated positively with anxiety-like behavior. The causal relationship between amygdala serotonin levels and an animal's sensitivity to threat was confirmed via direct amygdala infusions of a selective serotonin reuptake inhibitor (SSRI), citalopram. Both anxiety-like behaviors, and conditioned threat-induced responses were reduced by the blockade of serotonin reuptake in the amygdala. Together, these findings provide evidence that high amygdala serotonin transporter expression contributes to the high trait anxious phenotype and suggest that reduction of threat reactivity by SSRIs may be mediated by their actions in the amygdala.SIGNIFICANCE STATEMENT Findings here contribute to our understanding of how the serotonin system underlies an individual's expression of threat-elicited negative emotions such as anxiety and fear within nonhuman primates. Exploration of serotonergic gene expression across brain regions implicated in emotion regulation revealed that serotonin transporter gene expression in the ventrolateral prefrontal cortex (vlPFC) and most strongly in the amygdala, but none of the serotonin receptor genes, were predictive of interindividual differences in anxiety-like behavior. Targeting of amygdala serotonin reuptake with selective serotonin reuptake inhibitors (SSRIs) confirmed the causal relationship between amygdala serotonin transporter and an animal's sensitivity to threat by reversing expression of two key features of the high trait-like anxiety phenotype: high responsivity to anxiety-provoking uncertain threat and responsivity to certain conditioned threat.

Neural Connectivity Subtypes Predict Discrete Attentional Bias Profiles Among Heterogeneous Anxiety Patients

On average, anxious patients show altered attention to threat-including early vigilance towards threat and later avoidance of threat-accompanied by altered functional connectivity across brain regions. However, substantial heterogeneity within clinical, neural, and attentional features of anxiety is overlooked in typical group-level comparisons. We used a well-validated method for data-driven parsing of neural connectivity to reveal connectivity-based subgroups among 60 adults with transdiagnostic anxiety. Subgroups were externally compared on attentional patterns derived from independent behavioral measures. Two subgroups emerged. Subgroup A (68% of patients) showed stronger executive network influences on sensory processing regions and a paradigmatic "vigilance-avoidance" pattern on external behavioral measures. Subgroup B was defined by a larger number of limbic influences on sensory regions and exhibited a more atypical and inconsistent attentional profile. Neural connectivity-based categorization revealed an atypical, limbic-driven pattern of connectivity in a subset of anxious patients that generalized to atypical patterns of selective attention.

Grant Report on Anxiety-CBT: Dimensional Brain Behavior Predictors of CBT Outcomes in Pediatric Anxiety

In the following grant report, we describe initial and planned work supported by our National Institute of Mental Health R01-funded, Research Domain Criteria (RDoc) informed project, “Dimensional Brain Behavior Predictors of CBT Outcomes in Pediatric Anxiety”. This project examines response to cognitive behavioral therapy (CBT) in a large sample of anxiety-affected and low-anxious youth ages 7 to 18 years using multiple levels of analysis, including brain imaging, behavioral performance, and clinical measures. The primary goal of the project is to understand how brain-behavioral markers of anxiety-relevant constructs, namely acute threat, cognitive control, and their interaction, associate with CBT response in youth with clinically significant anxiety. A secondary goal is to determine whether child age influences how these markers predict, and/or change, across varying degrees of CBT response. Now in its fourth year, data from this project has informed the examination of (1) baseline (i.e., pre-CBT) anxiety severity as a function of brain-behavioral measures of cognitive control, and (2) clinical characteristics of youth and parents that associate with anxiety severity and/or predict response to CBT. Analysis of brain-behavioral markers before and after CBT will assess mechanisms of CBT effect, and will be conducted once the data collection in the full sample has been completed. This knowledge will help guide the treatment of clinically anxious youth by informing for whom and how does CBT work.

The Self and its World: A Neuro-Ecological and Temporo-Spatial Account of Existential Fear

The current international crisis situation caused by the COVID-19 pandemic is having a strong psychological impact on our subjectivities. We are constantly threatened by the danger of i) being infected, ii) infecting other people, and (iii) by the loss of social relation. Departing from these premises, we here aim to investigate the psychological and neurodynamics of this complex phenomenon. First, we discuss about recent psychological and neuronal findings on fear and its disorders, related to an unbalanced intero-exteroceptive processing and emotional regulation. Secondly we move to the psychological and neuronal dynamics of self and others characterized by a temporo-spatial alignment with the world. Due to the neural overlap of emotion and self and the deep-reaching neuro-ecological layers of self, emotional feelings like fear and anxiety cannot be detached and dissociated from the world; they signify the world–brain relation, and, more specifically, our self-other relation. The deepest neuro-ecological and neuro-social layers of self are threatened by the loss of subjectivity, which is manifest in our loss of body and thus the fear of dying, and the loss of intersubjectivity that surfaces in our fear of infecting others, which reflect the intimate anchorage of the self with the world. In our opinion the pandemic of COVID-19 deeply affect our sense of self and its spatio-temporal neuronal dynamics providing the prerequisites for the manifestation of fear and existential anxiety, thus disrupting the brain-world relation with significant repercussions on our psyche and on our daily lives.

Brain function and clinical characterization in the Boston adolescent neuroimaging of depression and anxiety study

We present a Human Connectome Project study tailored toward adolescent anxiety and depression. This study is one of the first studies of the Connectomes Related to Human Diseases initiative and is collecting structural, functional, and diffusion-weighted brain imaging data from up to 225 adolescents (ages 14-17 years), 150 of whom are expected to have a current diagnosis of an anxiety and/or depressive disorder. Comprehensive clinical and neuropsychological evaluations and longitudinal clinical data are also being collected. This article provides an overview of task functional magnetic resonance imaging (fMRI) protocols and preliminary findings (N = 140), as well as clinical and neuropsychological characterization of adolescents. Data collection is ongoing for an additional 85 adolescents, most of whom are expected to have a diagnosis of an anxiety and/or depressive disorder. Data from the first 140 adolescents are projected for public release through the National Institutes of Health Data Archive (NDA) with the timing of this manuscript. All other data will be made publicly-available through the NDA at regularly scheduled intervals. This article is intended to serve as an introduction to this project as well as a reference for those seeking to clinical, neurocognitive, and task fMRI data from this public resource.

Nonattachment Predicts Empathy, Rejection Sensitivity, and Symptom Reduction After a Mindfulness-Based Intervention Among Young Adults with a History of Childhood Maltreatment

Objectives

Individuals with a childhood maltreatment history tend to have various psychological symptoms and impaired social functioning. This study aimed to investigate the related therapeutic effects of a mindfulness-based intervention in this population.

Methods

We analyzed self-report questionnaire scores of the Mindful Attention Awareness Scale (MAAS), Non-Attachment Scale (NAS), Adult Rejection Sensitivity Questionnaire (A-RSQ), Interpersonal Reactivity Index (IRI), PTSD CheckList (PCL), and Anxiety Sensitivity Index (ASI), from 16 (3 males) young adults (age range 22-29) with mild to moderate childhood maltreatment, compared to 18 matched participants (6 males) on a waiting list, during both pre- and post-intervention/waiting periods. Analyses were conducted with linear mixed effects models, partial correlation analyses and t-tests.

Results

There were group by time interaction effects with the scores of MAAS, NAS, PCL, IRI-Fantasy, and A-RSQ (p < .05). The mindfulness group had significant increase in MAAS (17.325%) and NAS (8.957%) scores, as well as reduction in PCL (15.599%) and A-RSQ (23.189%) scores (p < .05). Changes in non-attachment, but not mindfulness, had significant contributions to the score changes of PCL (16.375%), ASI (36.244%), IRI-Personal Distress (24.141%), IRI-Empathic Concern (16.830%), and A-RSQ (10.826%) (p < .05). The number of intervention sessions attended was correlated with score changes of NAS (r = .955, p < .001), and ASI (r = -.887, p < .001), suggesting a dose-dependent effect.

Conclusions

Findings from this pilot study suggest that the mindfulness-based intervention improved mindfulness, non-attachment and empathy, which contributed to reduced interpersonal distress, rejection sensitivity and other psychological symptoms.

A novel-odour exploration test for measuring anxiety in adult and larval zebrafish

BACKGROUND

Existing methods to assess anxiety in zebrafish are mostly based on visual exploration. However, evidence suggests that zebrafish are more attuned to olfactory than visual stimuli. We developed a novel-odour exploration test (NOEt) for zebrafish.

NEW METHOD

Adult zebrafish were exposed to a stimulus sponge soaked with olfactory cue and a control sponge with no cue, placed at the extremities of a narrow, rectangular tank. We scored time spent close to the two sponges to calculate the attraction towards the olfactory cue. In experiment 1, we tested adult zebrafish in the NOEt using various olfactory cues. In experiment 2, we tested larvae. In experiment 3, we compared the NOEt with the most used method to assess anxiety, the open-field test.

RESULTS

In experiment 1, zebrafish responded markedly to cues, by either approaching or avoiding the soaked sponge according to the type of cue. The temporal pattern of exploration toward the cue was similar to that of novel objects' exploration in this species. In experiment 2, larvae responded to novel odours, but differently from adults. In experiment 3, we found a relationship between the NOEt and the open-field test.

COMPARISON WITH EXISTING METHOD(S)

Compared to existing tests, the NOEt has the advantage of exploiting the preferred sensory modality of zebrafish. Moreover, it can be used in early stages because olfactory receptors develop early in this species.

CONCLUSIONS

The NOEt is a simple, rapid and low-cost test to study anxiety in zebrafish using the spontaneous exploration of novel olfactory cues.

Missed targets, reaction times, and arousal are related to trait anxiety and attention to pain during an experimental vigilance task with a painful target

Although hypervigilance may play a role in some clinical pain syndromes, experimental vigilance toward painful stimuli has been studied infrequently. We evaluated vigilance toward pain by using a continuous performance task (CPT), in which subjects responded to moderately intense painful target stimuli, occurring in a train of mildly painful nontargets. We assessed nondetected targets (misses), reaction times (RTs), and psychological activation (tense arousal). During time on task in CPTs of other sensory modalities, there is an increase in misses and RTs (vigilance decrement). We hypothesized that our CPT would influence vigilance performance related to pain, anxiety, and limitation of attentional resources. The results showed a decrement in vigilance over time as misses increased, although RTs were unchanged. While mind-wandering did not influence vigilance performance, intrinsic attention to pain drove both hit RTs and number of misses. This resulted in pain-focused subjects performing worse on the CPT pain task with slower RTs and more misses per block. During the CPT, the change in stimulus salience was related to the change in pain intensity, while pain unpleasantness correlated with tense arousal. CPT performance during experimental vigilance to pain and psychological activation were related to trait anxiety, as measured by the Spielberger State-Trait Anxiety Inventory and neuroticism, as measured by the NEO five factor inventory. Trait anxiety and neuroticism may play important roles in an individual's predisposition to dwell on pain and interpret pain as threatening.NEW & NOTEWORTHY Subjects detected moderately painful target stimuli in a train of mildly painful nontarget stimuli, which resulted in vigilance performance metrics including missed targets, reaction times, and psychological activation. These performance metrics were related to intrinsic attention to pain and trait anxiety. Subjects with high trait anxiety and neuroticism scores, with a predisposition to attend to pain, had greater tense arousal and poorer vigilance performance, which may be important psychological aspects of vigilance to pain.

Dissociable neural systems for unconditioned acute and sustained fear

Fear protects organisms by increasing vigilance and preparedness, and by coordinating survival responses during life-threatening encounters. The fear circuit must thus operate on multiple timescales ranging from preparatory sustained alertness to acute fight-or-flight responses. Here we studied the brain basis of sustained and acute fear using naturalistic functional magnetic resonance imaging (fMRI) enabling analysis of different time-scales of fear responses. Subjects (N ​= ​37) watched feature-length horror movies while their hemodynamic brain activity was measured with fMRI. Time-variable intersubject correlation (ISC) was used to quantify the reliability of brain activity across participants, and seed-based phase synchronization was used for characterizing dynamic connectivity. Subjective ratings of fear were used to assess how synchronization and functional connectivity varied with emotional intensity. These data suggest that acute and sustained fear are supported by distinct neural pathways, with sustained fear amplifying mainly sensory responses, and acute fear increasing activity in brainstem, thalamus, amygdala and cingulate cortices. Sustained fear increased ISC in regions associated with acute fear, and also amplified functional connectivity within this network. The results were replicated in an independent experiment with a different subject sample and stimulus movie. The functional interplay between cortical networks involved in sustained anticipation of, and acute response to, threat involves a complex and dynamic interaction that depends on the proximity of threat, and the need to employ threat appraisals and vigilance for decision making and response selection.

Increased Anxiety After Stimulation of the Right Inferior Parietal Lobe and the Left Orbitofrontal Cortex

Sustained anxiety is a key symptom of anxiety disorders and may be associated with neural activation in the right inferior parietal lobe (rIPL), particularly under unpredictable threat. This finding suggests a moderating role of the rIPL in sustained anxiety, which we tested in the current study. We applied cathodal or sham transcranial direct current stimulation (tDCS) to the rIPL as a symptom provocation method in 22 healthy participants in a randomized, double-blind, crossover study, prior to two recordings of cerebral blood flow (CBF). In between, we applied a threat-of-shock paradigm with three conditions: unpredictable (U), predictable (P), or no electric shocks (N). We hypothesized increased anxiety under U, but not under P or N. Furthermore, we expected reduced CBF in the rIPL after tDCS compared to sham. As predicted, anxiety was higher in the U than the P and N conditions, and active tDCS augmented this effect. While tDCS did not alter CBF in the rIPL, it did attenuate the observed increase in brain regions that typically increase activation as a response to anxiety. These findings suggest that the rIPL moderates sustained anxiety as a gateway to brain regions crucial in anxiety. Alternatively, anodal tDCS over the left orbitofrontal cortex (lOFC) may have increased anxiety through disruption of OFC-amygdala interactions.

tDCS increases anxiety reactivity to intentional worry

While considerable experimental research has examined the impact of transcranial direct current stimulation (tDCS) on a range of cognitive processes associated with emotional pathology, the impact of tDCS on worry has been comparatively neglected. Given that anxiety pathology is characterised by motivated engagement in worry, and that frontal tDCS has the capacity to enhance goal-oriented cognition, it is important to examine whether tDCS would increase or ameliorate the cognitive and emotional effects of worry. In the current study we examined how tDCS influenced the anxiety response to worry, and the frequency of negative intrusive thoughts. We additionally examined whether stimulation delivered in isolation, or in combination with a mindful-focus task would augment the effects of tDCS. Ninety-seven (75 female) healthy participants received either active or sham anodal tDCS to the left dorsolateral prefrontal cortex, delivered either in isolation or concurrently with a mindful task (four conditions). The frequency of negative thought intrusions was assessed before and after a period of instructed worry, and state anxiety was assessed across the study. Active tDCS was associated with significantly greater elevation in anxiety in response to the worry induction. No effects were observed on the frequency of negative thought intrusions, and the combined delivery of tDCS with the concurrent mindful task did not alter the pattern of observed effects. While inviting replication in a high anxious sample, the present results highlight the possibility that tDCS may interact with motivated engagement in negative patterns of cognition, such as worry, to produce greater emotional reactivity.

Levels of early-childhood behavioral inhibition predict distinct neurodevelopmental pathways to pediatric anxiety

BACKGROUND

Anxiety symptoms gradually emerge during childhood and adolescence. Individual differences in behavioral inhibition (BI), an early-childhood temperament, may shape developmental paths through which these symptoms arise. Cross-sectional research suggests that level of early-childhood BI moderates associations between later anxiety symptoms and threat-related amygdala-prefrontal cortex (PFC) circuitry function. However, no study has characterized these associations longitudinally. Here, we tested whether level of early-childhood BI predicts distinct evolving associations between amygdala-PFC function and anxiety symptoms across development.

METHODS

Eighty-seven children previously assessed for BI level in early childhood provided data at ages 10 and/or 13 years, consisting of assessments of anxiety and an fMRI-based dot-probe task (including threat, happy, and neutral stimuli). Using linear-mixed-effects models, we investigated longitudinal changes in associations between anxiety symptoms and threat-related amygdala-PFC connectivity, as a function of early-childhood BI.

RESULTS

In children with a history of high early-childhood BI, anxiety symptoms became, with age, more negatively associated with right amygdala-left dorsolateral-PFC connectivity when attention was to be maintained on threat. In contrast, with age, low-BI children showed an increasingly positive anxiety-connectivity association during the same task condition. Behaviorally, at age 10, anxiety symptoms did not relate to fluctuations in attention bias (attention bias variability, ABV) in either group; by age 13, low-BI children showed a negative anxiety-ABV association, whereas high-BI children showed a positive anxiety-ABV association.

CONCLUSIONS

Early-childhood BI levels predict distinct neurodevelopmental pathways to pediatric anxiety symptoms. These pathways involve distinct relations among brain function, behavior, and anxiety symptoms, which may inform diagnosis and treatment.

Anticipation of aversive threat potentiates task-irrelevant attentional capture

Anxiety is believed to have a disruptive effect on attentional control, supported by evidence of increased distractibility among high trait anxious individuals. However, how feelings of current anxious apprehension influence selective attention is less well-understood. The present study examined this by assessing attentional capture by a novel distractor within a visual search task. Participants searched an array of coloured objects for a shape-defined target, while attempting to ignore a colour singleton distractor presented on half of the trials. To induce apprehension, participants completed the task in some blocks with a low probability threat of loud aversive sounds being presented. We found significantly increased distractibility within the threat condition when noise was anticipated but not played, as reflected by a larger distractor presence cost to reaction times. The finding that apprehension potentiates task-irrelevant attentional capture suggests a generalised role of anxious emotion in increasing distractibility.

Threat Anticipation in Pulvinar and in Superficial Layers of Primary Visual Cortex (V1). Evidence from Layer-Specific Ultra-High Field 7T fMRI

The perceptual system gives priority to threat-relevant signals with survival value. In addition to the processing initiated by sensory inputs of threat signals, prioritization of threat signals may also include processes related to threat anticipation. These neural mechanisms remain largely unknown. Using ultra-high-field 7 tesla (7T) fMRI, we show that anticipatory processing takes place in the early stages of visual processing, specifically in the pulvinar and V1.

The perceptual system gives priority to threat-relevant signals with survival value. In addition to the processing initiated by sensory inputs of threat signals, prioritization of threat signals may also include processes related to threat anticipation. These neural mechanisms remain largely unknown. Using ultra-high-field 7 tesla (7T) fMRI, we show that anticipatory processing takes place in the early stages of visual processing, specifically in the pulvinar and V1. When anticipation of a threat-relevant fearful face target triggered false perception of not-presented target, there was enhanced activity in the pulvinar as well as in the V1 superficial-cortical-depth (layers 1–3). The anticipatory activity was absent in the LGN or higher visual cortical areas (V2–V4). The effect in V1 was specific to the perception of fearful face targets and did not generalize to happy face targets. A preliminary analysis showed that the connectivity between the pulvinar and V1 superficial-cortical-depth was enhanced during false perception of threat, indicating that the pulvinar and V1 may interact in preparation of anticipated threat. The anticipatory processing supported by the pulvinar and V1 may play an important role in non-sensory-input-driven anxiety states.

Reduced Glutamate in the Medial Prefrontal Cortex Is Associated With Emotional and Cognitive Dysregulation in People With Chronic Pain

A decrease in glutamate in the medial prefrontal cortex (mPFC) has been extensively found in animal models of chronic pain. Given that the mPFC is implicated in emotional appraisal, cognition and extinction of fear, could a potential decrease in glutamate be associated with increased pessimistic thinking, fear and worry symptoms commonly found in people with chronic pain? To clarify this question, 19 chronic pain subjects and 19 age- and gender-matched control subjects without pain underwent magnetic resonance spectroscopy. Both groups also completed the Temperament and Character, the Beck Depression and the State Anxiety Inventories to measure levels of harm avoidance, depression, and anxiety, respectively. People with chronic pain had significantly higher scores in harm avoidance, depression and anxiety compared to control subjects without pain. High levels of harm avoidance are characterized by excessive worry, pessimism, fear, doubt and fatigue. Individuals with chronic pain showed a significant decrease in mPFC glutamate levels compared to control subjects without pain. In people with chronic pain mPFC glutamate levels were significantly negatively correlated with harm avoidance scores. This means that the lower the concentration of glutamate in the mPFC, the greater the total scores of harm avoidance. High scores are associated with fearfulness, pessimism, and fatigue-proneness. We suggest that chronic pain, particularly the stress-induced release of glucocorticoids, induces changes in glutamate transmission in the mPFC, thereby influencing cognitive, and emotional processing. Thus, in people with chronic pain, regulation of fear, worry, negative thinking and fatigue is impaired.

Alterations in heart-brain interactions under mild stress during a cognitive task are reflected in entropy of heart rate dynamics

Many people experience mild stress in modern society which raises the need for an improved understanding of psychophysiological responses to stressors. Heart rate variability (HRV) may be associated with a flexible network of intricate neural structures which are dynamically organized to cope with diverse challenges. HRV was obtained in thirty-three healthy participants performing a cognitive task both with and without added stressors. Markers of neural autonomic control and neurovisceral complexity (entropy) were computed from HRV time series. Based on individual anxiety responses to the experimental stressors, two subgroups were identified: anxiety responders and non-responders. While both vagal and entropy markers rose during the cognitive task alone in both subgroups, only entropy decreased when stressors were added and exclusively in anxiety responders. We conclude that entropy may be a promising marker of cognitive tasks and acute mild stress. It brings out a new central question: why is entropy the only marker affected by mild stress? Based on the neurovisceral integration model, we hypothesized that neurophysiological complexity may be altered by mild stress, which is reflected in entropy of the cardiac output signal. The putative role of the amygdala during mild stress, in modulating the complexity of a coordinated neural network linking brain to heart, is discussed.

Cognitive conflict could facilitate negative stimulus processing: evidence from trait anxiety in the flanker paradigm

The present study used event-related potentials to investigate the affective priming effect of cognitive conflict and the influence of trait anxiety during the early stage of conflict processing. Participants with relatively high-trait or low-trait anxiety were tested using a combination of flanker task (congruent or incongruent arrows) as primes presented 200 ms before positive or negative words as targets. Behavioral results showed that response times were shorter for negative targets following incongruent primes relative to congruent primes, and vice versa, suggesting that conflicts facilitated the processing of negative targets. Event-related potential results revealed that the N2 amplitudes (280-320 ms) for incongruent stimuli were significantly more negative than those for congruent stimuli, indicating a significant conflict effect. Moreover, the N400 amplitudes (580-680 ms) for positive targets after congruent primes were significantly more negative than those after incongruent primes, but no significant difference was found in the N400 amplitudes after congruent primes and incongruent primes for negative targets, indicating that conflicts had a negative effect on the subsequent processing. In addition, in the high-trait anxiety, the N400 amplitudes for negative targets after incongruent primes were significantly more negative than those after incongruent primes, and vice versa, indicating that conflicts facilitated the processing of negative targets. These findings showed that conflicts could facilitate the processing of negative targets and be viewed as aversive signals during the early stage of conflict processing and that high-trait anxiety promoted the negative effect induced by conflicts.

Regional cerebral perfusion correlates with anxiety in neuropsychiatric SLE: evidence for a mechanism distinct from depression

The study examined the hypothesis that hypoperfusion in brain areas known to be involved in emotional disturbances in primary psychiatric disorders is also linked to emotional difficulties in systemic lupus erythematosus (SLE) and that these are not secondary to the physical and social burden incurred by the disease. Nineteen SLE patients without overt neuropsychiatric manifestations (non-NPSLE), 31 NPSLE patients, and 23 healthy controls were examined. Dynamic susceptibility contrast MRI was used and cerebral blood flow and cerebral blood volume values were estimated in six manually selected regions of interest of brain regions suspected to play a role in anxiety and depression (dorsolateral prefrontal cortex, ventromedial prefrontal cortex, anterior cingulate cortex, hippocampi, caudate nuclei and putamen). NPSLE patients reported high rates of anxiety and depression symptomatology. Significantly reduced cerebral blood flow and cerebral blood volume values were detected in the NPSLE group compared to healthy controls in the dorsolateral prefrontal cortex and ventromedial prefrontal cortex, bilaterally. Within the NPSLE group, anxiety symptomatology was significantly associated with lower perfusion in frontostriatal regions and in the right anterior cingulate gyrus. Importantly, the latter associations appeared to be specific to anxiety symptoms, as they persisted after controlling for depression symptomatology and independent of the presence of visible lesions on conventional MRI. In conclusion, hypoperfusion in specific limbic and frontostriatal regions is associated with more severe anxiety symptoms in the context of widespread haemodynamic disturbances in NPSLE.

Overanxious and underslept

Are you feeling anxious? Did you sleep poorly last night? Sleep disruption is a recognized feature of all anxiety disorders. Here, we investigate the basic brain mechanisms underlying the anxiogenic impact of sleep loss. Additionally, we explore whether subtle, societally common reductions in sleep trigger elevated next-day anxiety. Finally, we examine what it is about sleep, physiologically, that provides such an overnight anxiety-reduction benefit. We demonstrate that the anxiogenic impact of sleep loss is linked to impaired medial prefrontal cortex activity and associated connectivity with extended limbic regions. In contrast, non-rapid eye movement (NREM) slow-wave oscillations offer an ameliorating, anxiolytic benefit on these brain networks following sleep. Of societal relevance, we establish that even modest night-to-night reductions in sleep across the population predict consequential day-to-day increases in anxiety. These findings help contribute to an emerging framework explaining the intimate link between sleep and anxiety and further highlight the prospect of non-rapid eye movement sleep as a therapeutic target for meaningfully reducing anxiety.

Nature and specificity of altered cognitive functioning in IBS

BACKGROUND

It is unknown whether cognitive dysfunction found in patients with irritable bowel syndrome (IBS) was attributable to the different subtypes, ongoing pathophysiological processes, trait characteristics, or psychiatric comorbidity.

METHODS

Forty Rome-III patients with IBS (20 diarrhea-predominant [IBS-D] and 20 constipation-predominant [IBS-C]) and 40 age-, sex-, education-matched healthy controls were systematically recruited and compared on their cognitive function with continuous performance test (CPT), Wisconsin Card Sorting Test (WCST) and emotional Stroop test. Beck Anxiety Inventory (BAI), Beck Depression Inventory-II (BDI-II), Patient Health Questionnaire-15 (PHQ-15) and a structured bowel symptom questionnaire were performed to measure anxiety, depressive, somatization, and bowel symptoms, respectively. Psychiatric diagnoses were ascertained with SCID-I (Structured Clinical Interview for DSM-IV Axis I Disorders).

KEY RESULTS

Patients with IBS showed significantly increased standard deviation of reaction time (SDRT) (P = .003) on CPT, increased failure to maintain set (FMS) (P=.002), and percentage of perseverative errors (P = .003) on WCST. SDRT did not correlate with illness chronicity or bowel symptoms. FMS correlated with bowel symptom severity. In logistic regression models controlled for BAI, BDI-II, and PHQ-15, SDRT (AOR = 1.08, P = .025), but not FMS (P = .25) or percentage of perseverative errors (P = .24), significantly differentiated IBS from controls. Cognitive function was not significantly different between IBS-C and IBS-D (P > .05), or between pure IBS (n = 22) and IBS with generalized anxiety disorder (GAD) (n = 17) (P > .05).

CONCLUSIONS & INFERENCES

Patients with IBS showed attentional and executive function impairment irrespective of subtypes but otherwise heterogeneous in terms of its state-trait correlations and overlap with anxiety comorbidity.

The neural substrates responsible for how trait anxiety affects delay discounting: Right hippocampal and cerebellar connectivity with bistable right inferior parietal lobule

Delay discounting, an indicator of impulsivity, refers to the extent of devaluing future rewards. Studies have found that individuals with trait anxiety generally depreciate the later larger rewards, showing steeper delay discounting rates. However, little is known about the neural substrates responsible for how trait anxiety affects individuals' delay discounting. To address this question, we employed the voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) methods to explore the neural substrates of trait anxiety responsible for delay discounting. Behavioral results showed that trait anxiety was significantly positively correlated with delay discounting rates. The VBM analysis revealed that gray matter volumes of the right hippocampus (RHPC) and right cerebellum (RCere) were significantly positively correlated with trait anxiety. Moreover, the RSFC results showed that bistable right inferior parietal lobule (RIPL) connectivity with the RHPC and RCere were all inversely associated with trait anxiety. More importantly, mediation analysis indicated that trait anxiety played a completely mediating role in the relation between functional connectivity of RHPC-RIPL and RCere-RIPL and delay discounting. These results suggested that bistable RIPL connectivity with RHPC and RCere could be neural substrates underlying the effect of trait anxiety on delay discounting. On the whole, the current study yields insights into how trait anxiety affects delay discounting and provides a novel account from a neural basis perspective.

Corticolimbic circuit structure moderates an association between early life stress and later trait anxiety

Childhood adversity is associated with a wide range of negative behavioral and neurodevelopmental consequences. However, individuals vary substantially in their sensitivity to such adversity. Here, we examined how individual variability in structural features of the corticolimbic circuit, which plays a key role in emotional reactivity, moderates the association between childhood adversity and later trait anxiety in 798 young adult university students. Consistent with prior research, higher self-reported childhood adversity was significantly associated with higher self-reported trait anxiety. However, this association was attenuated in participants with higher microstructural integrity of the uncinate fasciculus and greater thickness of the orbitofrontal cortex. These structural properties of the corticolimbic circuit may capture a neural profile of relative resiliency to early life stress, especially against the negative effects of childhood adversity on later trait anxiety.

Reward-related distracters and working memory filtering

Reward-related stimuli capture attention, even when they are task irrelevant. A consequence of attentional prioritization of reward-related stimuli is that they may also have preferential access to working memory like other forms of emotional information. However, whether reward-related distracters leak into working memory remains unknown. Here, using a well-validated change detection task of visual working memory capacity and filtering, we conducted two studies to directly assess the impact of reward-related distracters on working memory. In both studies, the distracters consisted of colored bars or circles that were previously associated with monetary reward. In Experiment 1, results indicated that previously rewarded distracters did not impact behavioral measures of working memory filtering efficiency compared to neutral distracters. In Experiment 2, using ERPs, we measured the contralateral delay activity (CDA), a psychophysiological index of the number of items retained in working memory, to further assess filtering efficiency. We observed that the CDA for high reward distracters was similar to low reward and neutral distracters. However, in early trials, behavioral measures revealed that previously rewarded stimuli negatively impacted working memory capacity, an effect not observed with neutral distracters. This effect, though, was not found for the CDA in early trials. In summary, our findings across two studies suggest that attentional capture by task-irrelevant reward may have minimal impact on visual working memory-findings that have important implications for delineating the boundaries of reward-cognition interactions.

Effects of Ego-Depletion and State Anxiety on Performance Changes in Dart-Throwing Tasks: A Latent Curve Model Approach Reporting Trial Data for Human Participants

This study examined the effects ego depletion (ED) and state anxiety (SA)have on performance changes in dart-throwing, a perceptual-motor task, using a Latent Curve Model (LCM). Twenty-two men, who had never played darts before, were recruited and randomly assigned to two counterbalanced groups: Group A was exposed first to ED and then to non-ED (NED), and Group B was exposed first to NED and then to ED. We found that the number of trials had a non-linear effect on darts performance, which improved as the number of trials increased before declining again; that is, mean radial error decreased first and then increased. Therefore, motor performance was sustained in the form of a quadratic curve as the number of task executions increased. In general, the higher the degree of ED and SA, the greater the negative effect on performance. However, this phenomenon was observed only in the early-phase trials, and the interacting influence of ED and SA appeared in the late-phase trials. Thus, this study demonstrated that ED and SA have direct effects on performance curves in early-phase trials only, and that their interacting influence appears in late-phase trials.

Effects of MDMA on attention to positive social cues and pleasantness of affective touch

The psychostimulant drug ±3,4-methylenedioxymethamphetamine (MDMA) reportedly produces distinctive feelings of empathy and closeness with others. MDMA increases social behavior in animal models and has shown promise in psychiatric disorders, such as autism spectrum disorder (ASD) and post-traumatic stress disorder (PTSD). How it produces these prosocial effects is not known. This behavioral and psychophysiological study examined the effects of MDMA, compared with the prototypical stimulant methamphetamine (MA), on two measures of social behavior in healthy young adults: (i) responses to socially relevant, "affective" touch, and (ii) visual attention to emotional faces. Men and women (N = 36) attended four sessions in which they received MDMA (0.75 or 1.5 mg/kg), MA (20 mg), or a placebo in randomized order under double-blind conditions. Responses to experienced and observed affective touch (i.e., being touched or watching others being touched) were assessed using facial electromyography (EMG), a proxy of affective state. Responses to emotional faces were assessed using electrooculography (EOG) in a measure of attentional bias. Subjective ratings were also included. We hypothesized that MDMA, but not MA, would enhance the ratings of pleasantness and psychophysiological responses to affective touch and increase attentional bias toward positive facial expressions. Consistent with this, we found that MDMA, but not MA, selectively enhanced ratings of pleasantness of experienced affective touch. Neither drug altered the ratings of pleasantness of observed touch. On the EOG measure of attentional bias, MDMA, but not MA, increased attention toward happy faces. These results provide new evidence that MDMA can enhance the experience of positive social interactions; in this case, pleasantness of physical touch and attentional bias toward positive facial expressions. The findings are consistent with evidence that the prosocial effects are unique to MDMA relative to another stimulant. Understanding the behavioral and neurobiological processes underlying the distinctive social effects of MDMA is a key step to developing the drug for psychiatric disorders.

Nicotine prevents anxiety-like behavioral responses in zebrafish

Anxiety-related disorders are severe psychiatric conditions that involve complex physiological and behavioral maladaptive responses. The use of conspecific alarm substance (CAS) for inducing anxiety-like behaviors in fish species provides important translational insights of how aversive conditions modulate neurobehavioral functions. Because nicotine may elicit anxiolytic-like responses, here we investigated whether acute nicotine exposure prevents CAS-induced anxiogenic-like behaviors in zebrafish. We used both novel tank and light-dark tests as two well-established paradigms for measuring anxiety-like phenotypes. Fish were individually exposed to 1 mg/L nicotine or non-chlorinated water for 3 min and then transferred to other tanks in the absence or presence of 3.5 mL/L CAS for 5 min. Later, the behavior of fish was tested in the novel tank test or in the light-dark preference test. As expected, CAS triggered aversive behaviors by increasing bottom-dwelling, freezing, erratic movements, scototaxis, and risk assessment episodes. Nicotine alone elicited anxiolytic-like behaviors since it increased the time spent in the top, as well as the average duration of entry in the lit compartment. Moreover, nicotine pretreatment prevented CAS-induced aversive responses without changing locomotion, suggesting that anxiolysis could play a role, at least in part, to the behavioral effects of nicotine observed here. Overall, these novel findings show the beneficial effects of nicotine on anxiogenic responses in zebrafish. We also reinforce the practical advantages of this aquatic species to explore the relieving properties of nicotine, as well as to understand the neurobiological bases involved in anxiety-related disorders and associated therapeutic targets.

Brain structural abnormalities in emotional regulation and sensory processing regions associated with anxious depression

BACKGROUND

Considerable patients with major depressive disorder (MDD) comorbid with anxious symptoms, referred as anxious depression. The neural structural basis of this MDD specifier remains largely unknown.

METHODS

104 patients with anxious depression, 57 MDD patients without significant anxious symptoms, and 160 healthy controls from single research center participated in the study with age and sex well-matched. We investigated gray matter alterations in anxious and non-anxious depression, explored different brain alterations between these two patient groups, and possible relationships between brain structural parameter and clinical information in patients.

RESULTS

Gray matter volumes differed in the right inferior frontal gyrus, right orbital frontal gyrus, left postcentral gyrus, bilateral culmen and left cuneus among the three groups. Anxious depression had smaller gray matter volumes in the right inferior frontal gyrus and orbital frontal gyrus relative to both non-anxious depression and healthy controls. Patients with anxious depression presented larger gray matter volumes in the left postcentral gyrus than non-anxious depression, and larger gray matter volumes in the left cuneus than healthy controls. In addition, both patient groups showed larger gray matter volumes in bilateral culmen relative to healthy controls. Gray matter volumes in the left postcentral gyrus were positively associated with overall depression severity and anxiety factor scores in anxious depression.

CONCLUSION

Our study revealed brain structural abnormalities in emotional regulation and sensory processing regions of anxious depression, which may suggested distinct neurobiological mechanisms of this MDD specifier and could help explain different clinical manifestations in anxious depression from pure depression.