Climate change on the brain: Neural correlates of climate anxiety.

Climate change is a global crisis impacting individuals' mental health. Climate anxiety is an emerging area of interest within popular culture and the scientific community. Yet, little is known about the mechanisms underlying climate anxiety. We provide evidence that climate anxiety is related to gray matter volume in the midcingulate cortex as well as its level of functional connectivity with the insula cortex. These neuroanatomical and neurofunctional features of climate anxiety are involved in identifying and anticipating potential threats within the environment and preparing an appropriate action response to such threats. These neural correlates align with those observed in anxiety disorders. Yet, climate anxiety itself as well as the neural correlates of climate anxiety were related to pro-environmental behavior. This may suggest that the midcingulate and insula are part of a network linked to an adaptive aspect of climate anxiety in motivating behavioral engagement.

Eye-size effects in the dot-probe task: Greater sclera exposure predicts delayed disengagement from fearful faces.

Fearful facial expressions are nonverbal and biologically salient signals of potential threat that automatically hold, capture, and direct observers' attention. They are characterized by enlarged eye whites and dilated pupils, and fearful eyes alone are sufficient to capture attention. The morphological properties of the eye region, such as sclera exposure, are thought to play an important role in nonverbal communication. Specifically, increased sclera exposure associated with fearful expressions has been shown to moderate how observers' shift their attention toward the direction of another's gaze. Yet, the extent to which variability in sclera exposure possibly impacts the capture and hold of attention by fearful faces is untested. To address this, a sample of 249 adults completed a dot-probe task of selective attention with fearful and neutral faces. The results suggested that (1) fearful faces were prioritized over neutral faces (i.e., they captured and held attention), (2) greater sclera exposure at target locations facilitated reaction times, and (3) attention was held by greater sclera exposure of fearful faces at task irrelevant locations resulting in delayed disengagement. Collectively, the results indicate that fearful facial expressions and sclera exposure modulate spatial attention through independent and interactive mechanisms. Sclera exposure appears to be an important facilitator of nonverbal communication and perhaps represents an understudied variable in social cognition more broadly.

The gray matter morphology associated with the electrophysiological response to errors in individuals with high trait anxiety.

Enhanced error monitoring has been associated with higher levels of anxiety. This has been consistently demonstrated in its most reliable electrophysiological index, the error-related negativity (ERN), such that increased ERN is related with elevated anxiety symptomology. However, it is still unclear whether the structural properties of the brain are associated with individual differences in ERN amplitude. Moreover, the relationship between ERN and anxiety has recently been suggested to be moderated by sex, but the degree to which sex moderates the association between brain structure and ERN amplitude is unknown. The present study investigated the association between gray matter volume (GMV) and ERN amplitude in individuals with high trait anxiety (N = 98) as well as the role of sex in moderating this association. The ERN was elicited from a flanker task, whereas structural MRI images were obtained from whole brain structural T1-weighted MRI scans. The results of voxel-based morphometry analyses showed that the relationship between ERN difference scores and GMV was moderated by sex in the dorsal anterior cingulate cortex (dACC). This sex difference was derived from a negative correlation between ERN difference scores and dACC GMV in females and a positive correlation in males. Our findings are in accordance with the critical role of the dACC serving as a neural substrate of error monitoring. It also provides further evidence for sex-specific associations with brain structures related to error monitoring.

Neuroplastic changes in anterior cingulate cortex gray matter volume and functional connectivity following attention bias modification in high trait anxious individuals.

Attention bias modification (ABM) was developed to alleviate anxious symptoms by way of a reduction in anxiety-linked attentional bias to threat. Central to the rational of ABM is a learning-related reconfiguration of attentional biases. Yet, the neuroplastic changes in brain structure that underlie this learning are unresolved. The amygdala, anterior cingulate cortex, and lateral prefrontal cortex are part of a system linked to attentional bias to threat and its modification with ABM. We assessed the extent to which ABM modulates gray matter volume and resting-state functional connectivity. Sixty-one individuals selected for attentional bias to threat and heightened trait anxiety completed a 6-week multi-session ABM protocol with 7200 total training trials. Participants were assigned to either an ABM (n = 30) or a control (n = 31) condition. We found that participants' levels of attentional bias and anxiety did not differ following ABM and control training interventions. However, the ABM group displayed greater levels of anterior cingulate cortex gray matter volume as well as greater superior frontal gyrus resting-state functional connectivity with the anterior cingulate cortex and insula. Changes in anterior cingulate cortex gray matter volume were linked to reduced anxious symptoms in the ABM, but not control, group. These findings suggest that ABM distinctively impacts structural and functional neural mechanisms associated with emotion reactivity and cognitive control processes.

Attentional bias to threat and gray matter volume morphology in high anxious individuals.

In a sample of highly anxious individuals, the relationship between gray matter volume brain morphology and attentional bias to threat was assessed. Participants performed a dot-probe task of attentional bias to threat and gray matter volume was acquired from whole brain structural T1-weighted magnetic resonance imaging scans. The results replicate previous findings in unselected samples that elevated attentional bias to threat is linked to greater gray matter volume in the middle frontal gyrus and superior frontal gyrus. In addition, we provide novel evidence that elevated attentional bias to threat is associated with greater gray matter volume in the inferior frontal gyrus, insula, cerebellum, and other distributed regions. Lastly, exploratory analyses provide initial evidence that distinct subregions of the right posterior parietal cortex may contribute to attentional bias in a sex-specific manner. Our results illuminate how differences in gray matter volume morphology relate to attentional bias to threat in anxious individuals. This knowledge could inform neurocognitive models of anxiety-related attentional bias to threat.

The questionable validity of attention bias variability: Evidence from two conceptually unrelated cognitive tasks.

Background: Attention bias variability is thought to measure fluctuations in attention towards and away from threat-related information and is elevated in affective disorders. However, recent evidence suggests that attention bias variability may quantify general reaction time variability rather than attention bias behavior per se. Methods: The current study calculated "attention bias variability" from two conceptually unrelated cognitive tasks: the dot-probe task (measuring attentional bias) and the arrow flanker task (measuring cognitive control). Results: Attention bias variability measures were correlated across these unrelated tasks. Yet, when general reaction time variability was controlled, attention bias variability across tasks was no longer correlated. In addition, the reliability of attention bias variability measures decreased when controlling for general reaction time variability. Finally, although attention bias variability calculated from the dot-probe task initially correlated with anxious symptoms, this association was no longer significant when controlling for general reaction time variability. Limitations: Our sample was comprised of high trait anxious individuals. Replication in clinical samples is warranted. Conclusions: These findings collectively provide strong empirical evidence that attention bias variability is not a valid measure of attention-related behavior, but reflective of general reaction time variability more broadly.

Reliability of attention bias and attention bias variability to climate change images in the dot-probe task.

Climate change is one of the most pressing issues of the 21st century, which is perhaps why information about climate change has been found to capture observers' attention. One of the most common ways of assessing individual differences in attentional processing of climate change information is through the use of reaction time difference scores. However, reaction time-based difference scores have come under scrutiny for their low reliability. Given that a primary goal of the field is to link individual differences in attention processing to participant variables (e.g., environmental attitudes), we assessed the reliability of reaction time-based measures of attention processing of climate change information utilizing an existing dataset with three variations of the dot-probe task. Across all three samples, difference score-based measures of attentional bias were generally uncorrelated across task blocks (r = -0.25 to 0.31). We also assessed the reliability of newer attention bias variability measures that are thought to capture dynamic shifts in attention toward and away from salient information. Although these measures were initially found to be correlated across task blocks (r = 0.17-0.67), they also tended to be highly correlated with general reaction time variability (r = 0.49-0.83). When controlling for general reaction time variability, the correlations across task blocks for attention bias variability were much weaker and generally nonsignificant (r = -0.25 to 0.33). Furthermore, these measures were unrelated to pro-environmental disposition indicating poor predictive validity. In short, reaction time-based measures of attentional processing (including difference score and variability-based approaches) have unacceptably low levels of reliability and are therefore unsuitable for capturing individual differences in attentional bias to climate change information.

Sex Differences in Anxiety: An Investigation of the Moderating Role of Sex in Performance Monitoring and Attentional Bias to Threat in High Trait Anxious Individuals.

Anxiety disorders are more predominant in women than men, however there is a lack of understanding as to what neurocognitive mechanisms drive this sex difference. Recent investigation has found a potential moderating role of sex in the relationship between anxiety and the error related negativity (ERN)-a component of error-monitoring that is prevalent in high anxiety individuals-such that females display a positive relationship between anxiety/worry and ERN amplitude. We strove to further explore the influence of sex on the relationship between trait anxiety and performance monitoring, specifically with ERN, as well as extend this work to include another hallmark of anxiety, attentional bias to threat. To meet this end, participants performed the flanker and dot-probe tasks, respectively. We did not find a significant difference in the relationship between attention bias scores and anxiety for female vs. males participants. Furthermore, ΔERN amplitudes were greater in males compared to females, and males had more positive CRN amplitudes than females. There were no significant associations between ERN or ΔERN with anxiety in both male and female participants. However, there was a significant relationship between CRN amplitudes and trait anxiety in male but not female participants. Given these results, the effect of sex on the relationship between components of performance monitoring-namely the CRN and ERN-and anxiety may be more nuanced than the current understanding. Our study was limited to detecting medium to large sized moderation effects. Our findings may be important for future meta-analysis on sex differences in anxiety.

Enhanced contralateral theta oscillations and N170 amplitudes in occipitotemporal scalp regions underlie attentional bias to fearful faces.

Attending toward fearful faces and other threatening stimuli increase the chance of survival. The dot-probe task is a commonly used measure of spatial attention. Event-related potentials (ERPs) have been found to be a reliable measure of attentional bias. The dot-probe literature suggests that posterior contralateral N170 amplitudes are more enhanced by fearful faces compared to ipsilateral amplitudes. However, ERP methods remove non-phase locked frequencies, which provides additional information about neural activity. Specifically, theta oscillations (5-7 Hz) have been linked to attentional processing. The purpose of this study was to examine the relationship between posterior contralateral theta oscillations and N170 amplitudes in the dot-probe task. A modified dot-probe task was used with fear and neutral facial expressions and EEG data was recorded from 33 electrodes. The ERP and time-frequency data were extracted from the P7 and P8 electrodes (left and right occipitotemporal regions). This study found enhanced N170 amplitude and theta oscillations in the electrodes posterior contralateral to the fearful face. Contralateral N170 amplitudes and theta oscillations were related such that greater N170 amplitudes were associated with greater theta oscillations. The results indicated that increased contralateral N170 and theta oscillations are related to each other and underlie attentional bias to fearful faces.

A systematic review of event-related potentials as outcome measures of attention bias modification.

Attention bias modification (ABM) was initially developed with the goal of reducing attentional bias to threat-and subsequently anxious symptoms-in individuals with heightened anxiety. Although controversial, ABM appears to be generally effective in achieving this goal. Yet, the primary outcome measure of ABM (i.e., the reaction time-based differences score) has poor reliability and temporal resolution, which limits the inferences that can be drawn. In contrast, event-related potentials (ERPs) have superior reliability as well as temporal resolution and may therefore be better outcome measures of ABM. In this review, I systematically assess the research using ERPs as outcome measures in ABM protocols. I focus on the extent to which the ERPs modified by ABM represent earlier or later stages of information processing. In addition, I explore the extent to which ABM produces near and/or far transfer of learning effects on ERP measures. The reviewed literature suggests that ERPs are promising outcome measures of ABM. ABM modulates the effects of affective stimuli on posterior visually evoked ERPs (i.e., P1) as well as ERPs at anterior electrodes (i.e., P2, N2, and ERN). Based on the state of the field, several directions for future research are identified.

Dorsal anterior cingulate cortex intrinsic functional connectivity linked to electrocortical measures of error monitoring.

The error-related negativity (ERN) is a response-locked event-related potential, occurring approximately 50 ms following an erroneous response at frontocentral electrode sites. Source localization and functional magnetic resonance imaging (fMRI) research indicate that the ERN is likely generated by activity in the dorsal anterior cingulate cortex (dACC). The dACC is thought to be a part of a broader network of brain regions that collectively comprise an error monitoring network. However, little is known about how intrinsic connectivity within the dACC-based error monitoring network contributes to variability in ERN amplitude. The purpose of this study was to assess the relationship between dACC functional connectivity and ERN amplitude. In a sample of highly trait anxious individuals, the ERN was elicited in a flanker task and functional connectivity was assessed in a 10-min resting-state fMRI scan. Results suggest that the strength of dACC seeded functional connectivity with the supplementary motor area is correlated with the ΔERN (i.e., incorrect-correct responses) amplitude such that greater ΔERN amplitude was accompanied by greater functional coupling between these regions. In sum, ERN amplitude appears to be related to the strength of functional connectivity between error monitoring and motor control regions of the brain.

Single session positive attention bias modification training enhances reward-related electrocortical responses in females.

Positive affect is linked to greater mental and physiological well-being. Conversely, negative affect is linked to depressive symptoms such as anhedonia. Relative biases in attention to positive or negative emotional information are thought to underlie individual difference in positive and negative affective traits, respectively. Attention bias modification (ABM) increases positive affect by training attention away from negative, or toward positive, stimuli. ABM training to reduce bias to negative information modulates electrocortical activity (i.e., P2, N2, & P3 ERP amplitudes), and this effect is moderated by participant sex. The extent to which ABM training to positive stimuli alters electrocortical activity and the extent to which such changes are moderated by participant sex is unknown. Here, participants completed attend positive ABM (or control) training followed by assessments of attentional bias, mood, and reward-related electrocortical activity. The results provide evidence of greater attentional bias to positive information following ABM. Transfer of these training effects to electrocortical measures was found for the P2 ERP component and moderated by participant sex. Females displayed a larger P2 amplitude for positive outcomes following ABM training. The reward positivity (RewP) and P3 ERPs were not directly affected by training, but the relationship between ERPs was linked to training such that following ABM training, the P2 and RewP components were strongly correlated, while following control training, the P3 and RewP were moderately correlated. Thus, ABM training to positive information enhanced electrocortical measures of reward processing in females and increased the relationship between reward-related ERPs.

Electrocortical responses associated with attention bias to fearful facial expressions and auditory distress signals.

Understanding how emotional stimuli across auditory and visual sensory domains interact and influence multimodal attentional mechanisms is important to understanding how humans prioritize and isolate emotionally-laden stimuli in a continual stream of sensory information that occurs in everyday life. While multimodal emotional human-relevant stimuli have been used in the past, this study is one of the first to look at how human-generated threat-related sounds (e.g., screams) interact with human-generated visual cues of threat (fearful facial expressions) to determine whether these converging sources of threat are represented by either combined or isolated enhancements of visual attention as measured with event-related potential (ERP) components related to attention: the N170, N2, and N2pc. Using the dot-probe task, this study demonstrates that converging sources of multimodal audiovisual threat interact to modulate the N170 ERP component such that auditory distress signals widen the spotlight of attention beyond the contralateral enhancement elicited by the fearful face cue. Multimodal facilitation was neither observed on the N2pc nor the anterior N2. Rather, separate unimodal effects were observed on these ERP components.

Sport-related concussion is associated with elevated anxiety, but not attentional bias to threat.

Primary Objective: Symptoms following concussion commonly include deficits in attentional processing and elevated anxiety. Prioritized allocation of attentional resources to threat-related information is referred to as attentional bias to threat, which is a cardinal symptom - and in some cases a causal factor in the development - of anxiety. Here, we aimed to assess two possibilities regarding the relationship between attentional bias and anxiety in the post-concussive phase of sport-related concussion: (1) attentional bias mediates the relationship between concussion and anxiety or (2) attentional bias and concussion are uniquely associated with anxiety.Research Design: A cross-sectional between-groups design was used to assess differences in anxiety and attentional bias to threat between collegiate athletes with a recent sport-related concussion and a matched control group.Methods and Procedures: Forty-two collegiate athletes, 21 with a sport-related concussion and 21 matched controls, completed the dot-probe task of attentional bias and an anxiety questionnaire.Main Outcomes and Results: Anxiety, but not attentional bias, is elevated in concussion. Additionally, concussion and attentional bias to threat appear to be uniquely associated with anxiety symptoms.Conclusions: Unique treatment/rehabilitation strategies should be considered for individuals with elevated anxiety following concussion.

The stability and reliability of attentional bias measures in the dot-probe task: Evidence from both traditional mean bias scores and trial-level bias scores.

A new method of calculating attentional bias from the dot-probe task measures fluctuations in bias towards and away from emotional stimuli over time using trial level bias score metrics. We assessed the stability and reliability of traditional attentional bias scores and trial level bias score measures of attentional bias across time in two five-block dot-probe task experiments in non-clinical samples. In experiments 1 and 2, both traditional attentional bias scores and trial level bias score measures of attentional bias did not habituate/decrease across time. In general, trial level bias score metrics (i.e., attention bias variability as well as the mean biases toward and away from threat) were more reliable than the traditional attention bias measure. This pattern was observed across both experiments. The traditional bias score, however, did improve in reliability in the later blocks of the fearful face dot-probe task. Although trial level bias score measures did not habituate and were more reliable across blocks, these measures did not correlate with state or trait anxiety. On the other hand, trial level bias score measures were strongly correlated with general reaction time variability-and after controlling for this effect no longer superior in reliability in comparison to the traditional attention bias measure. We conclude that general response variability should be removed from trial level bias score measures to ensure that they truly reflect attention bias variability.

Neural correlates of aversive anticipation: An activation likelihood estimate meta-analysis across multiple sensory modalities.

Anticipation is a universal preparatory response essential to the survival of an organism. Although meta-analytic synthesis of the literature exists for the anticipation of reward, a neuroimaging-based meta-analysis of the neural mechanisms of aversive anticipation is lacking. To address this gap in the literature, we ran an activation likelihood estimate (ALE) meta-analysis of 63 fMRI studies of aversive anticipation across multiple sensory modalities. Results of the ALE meta-analysis provide evidence for a core circuit involved in aversive anticipation, including the anterior insula, anterior cingulate cortex, mid-cingulate cortex, amygdala, thalamus, and caudate nucleus among other regions. Direct comparison of aversive anticipation studies using tactile versus visual stimuli identified additional regions involved in sensory specific aversive anticipation across these sensory modalities. Results from complementary multi-study voxel-wise and NeuroSynth analyses generally provide converging evidence for a core circuit involved in aversive anticipation. The multi-study voxel-wise analyses also implicate a more widespread preparatory response across sensory, motor, and cognitive control regions during more prolonged periods of aversive anticipation. The potential roles of these structures in anticipatory processing as well as avenues for future research are discussed.

Affective Images of Climate Change.

Climate change is not only a scientific phenomenon, but also a cultural one. Individuals' opinions on climate change are often based on emotion rather than on scientific evidence. Therefore, research into the emotional characteristics of the imagery that the non-expert public find relevant to climate change is important in order to build a database of effective climate change imagery, which can then be used by scientists, policymakers, and practitioners in mobilizing climate adaptation and resilience efforts. To this end, we collected ratings of relevance to climate change as well as emotional arousal and valence on 320 images to assess the relationship between relevance to climate change and the emotional qualities of the image. In addition, participants' environmental beliefs were measured, to investigate the relationship between beliefs and image ratings. The results suggest that images rated highly relevant to climate change are higher in negative emotional valence and emotional arousal. Overall, images were rated as being more relevant to climate change by participants with higher pro-environmental disposition. Critically, we have compiled the mean relevance, valence, and arousal ratings of each of these 320 images into a database that is posted online and freely available (https://affectiveclimateimages.weebly.com; https://www.nmu.edu/affectiveclimateimages) for use in future research on climate change visuals.

Variability in anterior insula grey matter volume correlates with awareness for peri-threshold backward-masked fearful faces.

The threshold for conscious perception of stimuli within the environment varies from individual to individual. Functional neuroimaging studies have suggested that insular cortex activity is positively correlated with perceptual awareness. However, few studies have tested the relationship between awareness and structural variability in the insula. The purpose of this study was to examine structural differences in brain morphology related to perceptual awareness of fearful faces. This study hypothesized that there would be a positive correlation between insular grey matter volume and scores on the forced-choice awareness check task. The forced-choice awareness check task was designed to assess awareness for the presence and location of backward masked fearful and neutral faces, masked with neutral faces. The participants responded by indicating the side on which the masked fearful face appeared, or whether there were two neutral faces. The task included a total of 60 trials. T1-weighted magnetic resonance images were collected to measure grey matter volumes. Individuals that were more aware of backward masked fearful faces had greater grey matter volume in the insula, middle cingulate, anterior temporal pole, ventral striatum, and hippocampus.

No Money, No Problem: Enhanced Reward Positivity in the Absence of Monetary Reward.

The reward-related positivity (RewP) is an event-related potential (ERP) with a positive amplitude occurring approximately 250-350 ms post-feedback at frontocentral electroencephalogram (EEG) electrode sites. The RewP is typically elicited in monetary gambling tasks and has a relatively larger amplitude for positive vs. negative outcomes. However, the extent to which RewP amplitude is modulated by non-monetary feedback is less clear. To address this issue, EEG was used to record reward-related electrocortical activity during a simple non-monetary gambling task. We hypothesized that the RewP would be enhanced for non-monetary wins relative to losses, which was supported by the results. In our supplementary material, we provide additional analyses suggesting that this effect was not observed for the P3. In sum, RewP amplitudes were larger for positive (nonmonetary) feedback relative to negative feedback at frontocentral electrode sites-suggesting that monetary reward is not necessary to elicit the RewP.

Climate change images produce an attentional bias associated with pro-environmental disposition.

Humans have developed mechanisms to prioritize certain sensory input(s). Emotionally salient stimuli automatically capture observers' attention at the cost of less salient information. This prioritized processing is called attentional bias. Images of climate change have been found to elicit emotional responses. Yet, to date, there is no research assessing the extent to which climate change-relevant images produce an attentional bias. In a sample of college students (N = 39), we found that (1) climate change-related images capture attention and that (2) this attentional bias is related to individual differences in environmental disposition. Thus, images of climate change are salient-attention grabbing-signals related to pro-environmental orientation.