The neurophysiological relationship between number anxiety and the EEG gamma-band

ABSTRACT

The development of math anxiety is thought to originate at a young age, as a form of number anxiety, but has not been investigated extensively. Research has shown greater levels of EEG gamma-band activity are experienced during threat perception and attentional bias. This has been identified in high math anxious individuals when confronted with math-based tasks, but has not yet been explored for number anxiety specifically. Single-digit numbers and letters were presented to 15 high and 15 low math anxious participants, who were required to observe the stimuli. High math anxious participants displayed significantly greater levels of gamma activity during number observation compared to letter observation. Findings suggest high math anxious individuals may have a threat-related response to observation of simple numerical stimuli. Further behavioural investigations are needed, but high math anxious individuals may display avoidance towards number and math due to a threat response associated with increased gamma activity.     

Emotional context influences access of visual stimuli to anxious individuals' awareness

Anxiety has been associated with enhanced unconscious processing of threat and attentional biases towards threat. Here, we focused on the phenomenology of perception in anxiety and examined whether threat-related material more readily enters anxious than non-anxious individuals' awareness. In six experiments, we compared the stimulus exposures required for each anxiety group to become objectively or subjectively aware of masked facial stimuli varying in emotional expression. Crucially, target emotion was task irrelevant. We found that high trait-anxiety individuals required less sensory evidence (shorter stimulus exposure times) to become aware of the face targets. This anxiety-based difference was observed for fearful faces in all experiments, but with non-threat faces, it emerged only when these were presented among threatening faces. Our findings suggest a prominent role for affective context in high-anxiety individuals' conscious perception of visual stimuli. Possible mechanisms underlying the influence of context in lowering awareness thresholds in anxious individuals are discussed.     

Direction of threat attention bias predicts treatment outcome in anxious children receiving cognitive-behavioural therapy

BackgroundA bias to selectively direct attention to threat stimuli is a cognitive characteristic of anxiety disorders. Recent studies indicate that individual differences in pre-treatment threat attention bias predict treatment outcomes from cognitive-behavioural therapy (CBT) in anxious individuals. However, there have been inconsistent findings regarding whether attention bias towards threat predicts better or poorer treatment outcome.MethodThis longitudinal study examined treatment outcomes in 35 clinically-anxious children following a 10-week, group-based CBT program, as a function of whether children showed a pre-treatment attention bias towards or away from threat stimuli. The effect of CBT on attention bias was also assessed.ResultsBoth groups showed significant improvement after receiving CBT. However, anxious children with a pre-treatment attention bias towards threat showed greater reductions not only in anxiety symptom severity, but also in the likelihood of meeting diagnostic criteria for anxiety disorders at post-treatment assessment, in comparison with anxious children who showed a pre-treatment attention bias away from threat. Children who had a pre-treatment bias away from threat showed a reduction in this bias over the course of CBT.ConclusionsFindings suggest that pre-existing differences in the direction of attention towards versus away from threat could have important implications for the treatment of anxious children.     

Health anxiety,anxiety sensitivity,and attentional biases for pictorial and linguistic health‐threat cues

The study investigated attentional biases for pictorial and linguistic health‐threat stimuli in high and low health anxious individuals, who were selected from the upper and lower quartile ranges of a normal sample using a screening measure of health anxiety. Attentional bias was assessed using a visual probe task which presented health‐threat and neutral pictures and words at two exposure durations, 500 ms and 1250 ms. The prediction that the high health anxious group would show a greater attentional bias for health‐threat cues than the low health anxious group was not supported despite the groups being well‐differentiated on a general measure of health anxiety, the Illness Attitudes Scale (IAS). Instead, the results indicated that individuals with high levels of anxiety sensitivity showed a significantly greater initial attentional bias for threat pictures compared with those with low anxiety sensitivity, as assessed by the Anxiety Sensitivity Index (ASI).     

Selective attention to threat: A test of two cognitive models of anxiety

Two experiments evaluated differential predictions from two cognitive formulations of anxiety. According to one view, attentional biases for threat reflect vulnerability to anxiety; and as threat inputs increase, high trait anxious individuals should become more vigilant, and low trait individuals more avoidant, of threat (Williams, Watts, MacLeod, & Mathews, 1988, 1997). However, according to a “cognitive-motivational” view, trait anxiety influences the appraisal of stimulus threat value, rather than the direction of attentional bias, and both high and low trait anxious individuals should exhibit greater vigilance for high rather than mild threat stimuli (Mogg & Bradley, 1998). To test these predictions, two experiments examined the effect of manipulating stimulus threat value on the direction of attentional bias. The stimuli included high threat and mild threat pictorial scenes presented in a probe detection task. Results from both studies indicated a significant main effect of stimulus threat value on attentional bias, as there was increased vigilance or reduced avoidance of threat, as threat value increased. This effect was found even within low trait anxious individuals, consistent with the “cognitive-motivational” view. Theoretical and clinical implications are discussed.     

Individual differences in perceptual sensitivity and response bias in anxiety: Evidence from emotional faces

We investigated the perception of emotional stimuli in anxious individuals and non-anxious cohorts. Signal detection theory analysis was applied to the discrimination of emotionally charged faces at several points along a continuum of emotional intensity. This design permitted the derivation of multiple measures of sensitivity and response bias for fearful and for happy faces. Anxious individuals lacked a conservative bias in judging fearful stimuli and a liberal bias in judging positive stimuli compared with non-anxious individuals. In addition, anxious participants had lower perceptual sensitivity (d′) than non-anxious participants for mildly threatening stimuli, as well as a trend towards lower perceptual sensitivity for moderately positive stimuli. These results suggest that the processing of threat information in anxiety is affected by sensitivity and bias differently at different levels of affective intensity.     

Anxiety and Attention: Is There an Attentional Bias for Positive Emotional Stimuli?

Empirical research has shown that anxiety is associated with a systematic bias in the cognitive system. Anxious individuals (clinically anxious patients and normal individuals with high-trait anxiety) are characterized by a pattern of selective processing that favors the encoding of threatening information. Is this attentional bias specific to threat-related information, or does it operate for positive emotional stimuli? The research directly connected with the existence of an attentional bias for threat in anxiety was examined.     

Contrasting two accounts of anxiety-linked attentional bias: selective attention to varying levels of stimulus threat intensity

Previous research has established that clinical anxiety patients and nonclinical populations with high levels of anxiety vulnerability characteristically orient attention toward moderately threatening stimuli. In contrast, populations with low levels of anxiety vulnerability typically orient attention away from such stimuli. The differing experimental predictions generated by 2 classes of hypothetical explanation for this anxiety-linked attentional discrepancy were tested, using attentional probe methodology to compare the attentional responses of high and low trait anxious individuals to facial stimuli of differing threat intensities. The results support the view that all individuals orient attention away from mildly threatening stimuli and toward strongly threatening stimuli, with differences in anxiety vulnerability reflecting the intensity of stimulus threat required to elicit the attentional vigilance response.     

Conscious intrusion of threat information via unconscious priming in anxiety

Preferential processing of threat has been implicated in the development and perpetuation of anxiety. We investigated threat processing and anxiety using a subliminal priming paradigm. People with high or low trait anxiety viewed masked, briefly presented words, and then took an exclusion-completion test in which three-letter stems were to be completed without using recently perceived words. Completion rates were greater for words viewed subliminally compared to a baseline estimate. In addition, unconscious priming was greater for threat than for neutral words in the high-trait-anxiety group, and for neutral than for threat words in the low-trait-anxiety group. Enhanced unconscious priming of threat completions among anxious individuals may model intrusions in anxiety, when unconscious processing breaks into consciousness in the form of threat-related intrusive thoughts.     

Health anxiety, anxiety sensitivity, and attentional biases for pictorial and linguistic health-threat cues

The study investigated attentional biases for pictorial and linguistic health-threat stimuli in high and low health anxious individuals, who were selected from the upper and lower quartile ranges of a normal sample using a screening measure of health anxiety. Attentional bias was assessed using a visual probe task which presented health-threat and neutral pictures and words at two exposure durations, 500 ms and 1250 ms. The prediction that the high health anxious group would show a greater attentional bias for health-threat cues than the low health anxious group was not supported despite the groups being well-differentiated on a general measure of health anxiety, the Illness Attitudes Scale (IAS). Instead, the results indicated that individuals with high levels of anxiety sensitivity showed a significantly greater initial attentional bias for threat pictures compared with those with low anxiety sensitivity, as assessed by the Anxiety Sensitivity Index (ASI).     

Attentional bias to threat: Roles of trait anxiety, stressful events, and awareness

Attentional biases for threat stimuli were assessed in high and low trait anxious subjects (n = 66) using a probe detection task. To examine the effects of trait anxiety and situational stressors, each subject was tested three times: Under no stress, laboratory-induced stress, and examination-induced stress. To evaluate the role of awareness, half the word stimuli were presented very briefly (14 msec) and masked, and the other half were presented for 500 msec without a mask. Results showed that high trait anxious subjects under exam stress showed an attentional bias towards unmasked threat stimuli compared with low trait subjects. This effect was not found under lab-induced stress, suggesting that the attentional bias for unmasked threat in high trait subjects may be a function of a prolonged stressor, rather than a transient increase in state anxiety. The results from the masked exposure condition were not predicted; high trait anxious subjects shifted attention towards the spatial location of threat words despite lack of awareness of their lexical content, but this bias was only apparent in the no-stress condition. The results are discussed in relation to recent cognitive theories of anxiety.     

Time-course of attention for threatening pictures in high and low trait anxiety

Cognitive studies about anxiety suggest that the interplay between automatic and strategic biases in attention to threat is related to the persistence of fear. In the present study, the time-course of attention to pictures with varying threat levels was investigated in high trait anxious (HTA, n=21) and low trait anxious (LTA, n=22) students. In a visual probe detection task, high and mild threat pictures were presented at three durations: 100, 500, and 1250 ms. Results indicated that all individuals attended to the high threat pictures for the 100 ms condition. Differential responding between HTA and LTA individuals was found for the 500 ms condition: only HTA individuals showed an attentional bias for mild threatening stimuli. For the 1250 ms condition, the HTA individuals attended away from high and mild threat pictures. The observed pattern of differential attention to threatening pictures may explain the persistence of fear in HTA individuals.     

Threat-related attentional bias in anxious and nonanxious individuals: a meta-analytic study

This meta-analysis of 172 studies (N = 2,263 anxious,N = 1,768 nonanxious) examined the boundary conditions of threat-related attentional biases in anxiety. Overall, the results show that the bias is reliably demonstrated with different experimental paradigms and under a variety of experimental conditions, but that it is only an effect size of d = 0.45. Although processes requiring conscious perception of threat contribute to the bias, a significant bias is also observed with stimuli outside awareness. The bias is of comparable magnitude across different types of anxious populations (individuals with different clinical disorders, high-anxious nonclinical individuals, anxious children and adults) and is not observed in nonanxious individuals. Empirical and clinical implications as well as future directions for research are discussed.     

非自主闯入焦虑发生的机制：阈下启动效应的实验研究

本研究采用阈下情感启动范式, 研究威胁信息启动效应及其特质焦虑的调节作用,旨在揭示焦虑非自主闯入性特点形成的机制。实验在随机的三种条件下（阈上/阈下/基线）给38名被试呈现两种目标词（威胁词和中性词）,其中基线条件不呈现目标词;之后要求被试在回避目标词的条件下完成组词任务,结果：（1）无论是中性词还是威胁词,被试阈下条件下目标词的击中率显著高于基线条件;（2）特质焦虑对阈下启动效应起着调节作用：高焦虑组被试威胁词的启动效应显著高于中性词,低焦虑组被试中性词的启动效应显著高于威胁词。结论：阈下启动效应显著,高特质焦虑组个体对威胁信息的无意识加工会增强对威胁信息的意识加工,产生闯入性想法,导致焦虑非自主闯入性的特点。     

Assessing the role of spatial engagement and disengagement of attention in anxiety-linked attentional bias: a critique of current paradigms and suggestions for future research directions

A considerable volume of research has demonstrated an anxiety-linked attentional bias characterized by selective processing of threat stimuli. The last decade has seen growing interest in identifying the precise attentional mechanisms which underlie such selective processing to advance both theoretical and etiological models of anxiety. This research has particularly focused on the roles of spatial engagement and disengagement of attention. The relative contribution of these attentional components to selective processing of threat in anxious individuals remains unclear however. Moreover, we argue here that many of the tasks employed to examine these mechanisms, may not be capable of indexing the attentional processes that they claim to measure. In this article, we provide a methodological review, critically evaluating the adequacy of previous tasks employed to measure biased attentional engagement and disengagement. Based on a number of concerns raised about the ability of such tasks to differentiate these component attentional processes, we detail three task criteria that we believe are essential to be confident that a task will accurately index biased attentional engagement with, and disengagement from threat in anxious participants.     

EEG gamma-band response during the perception of Necker cube reversals

In two former studies our research group reported frontal gamma-band enhancement during multistable visual perception and reversal rate dependent differences in the gamma-band. In these studies, a dynamic reversible figure was used which was based on the phenomenon of apparent motion. The aim of this study was to examine whether the results obtained with a dynamic motion paradigm can be replicated with the static Necker cube. The results demonstrate a general frontal gamma-band enhancement and higher induced gamma activity for subjects with a relatively high reversal rate in comparison to subjects with a relatively low reversal rate. This pattern of results fits well to the findings obtained with the dynamic motion paradigm. Therefore, the important role of frontal gamma activity for figure reversals has received further evidence. The results support the involvement of attentional top-down processing of figure reversal that is not directly related to binding processes.     

Biased attentional processing of positive stimuli in social anxiety disorder: an eye movement study

Despite the established relationship between social anxiety and attentional bias towards threat, a growing base of evidence suggests that social anxiety is additionally maintained by a deficit in the attentional processing of positive information. However, it remains unclear which component of attention is implicated in this deficit. Using eye movement-based measures and a novel attentional cuing methodology, the present study sought to investigate the presence of anxiety-linked bias in attentional engagement with, attentional disengagement from, and total fixation time to, socially relevant emotional stimuli in individuals diagnosed with social anxiety disorder, relative to non-socially anxious controls. Socially anxious individuals were found to exhibit faster attentional disengagement from positive stimuli, and reduced total fixation time to all emotional stimuli, relative to controls. Additionally for socially anxious individuals, lower total fixation times to positive stimuli were associated with higher levels of state anxiety. No differential pattern of engagement was evident between groups. We conclude that social anxiety is maintained in part by the aberrant processing of positive social stimuli.     

Mental Imagery and Post-Event Processing in Anticipation of a Speech Performance Among Socially Anxious Individuals

The present study investigated whether post-event processing (PEP) involving mental imagery about a past speech is particularly detrimental for socially anxious individuals who are currently anticipating giving a speech. One hundred fourteen high and low socially anxious participants were told they would give a 5 min impromptu speech at the end of the experimental session. They were randomly assigned to one of three manipulation conditions: post-event processing about a past speech incorporating imagery (PEP-Imagery), semantic post-event processing about a past speech (PEP-Semantic), or a control condition, (n = 19 per experimental group, per condition [high vs low socially anxious]). After the condition inductions, individuals’ anxiety, their predictions of performance in the anticipated speech, and their interpretations of other ambiguous social events were measured. Consistent with predictions, high socially anxious individuals in the PEP-Imagery condition displayed greater anxiety than individuals in the other conditions immediately following the induction and before the anticipated speech task. They also interpreted ambiguous social scenarios in a more socially anxious manner than socially anxious individuals in the control condition. High socially anxious individuals made more negative predictions about their upcoming speech performance than low anxious participants in all conditions. The impact of imagery during post-event processing in social anxiety and its implications are discussed.     

Is there a mutual relationship between opposite attentional biases underlying anxiety?

Current models that account for attentional processes in anxiety have proposed that high-trait anxious individuals are characterized by a hypervigilant-avoidant pattern of attentional biases to threat. We adopted a laboratory conditioning procedure to induce concomitant hypervigilance and avoidance to threat, emphasizing a putative relationship between lower-level reactive and upper-level controlled attentional mechanisms as the core account of attentional processes involved in the development and maintenance of anxiety. Eighty high- and low-trait anxious participants underwent Pavlovian conditioning to a human face. Eye tracking was used to monitor attentional changes to the conditioned stimulus (CS+) face and the neutral stimulus (CS-) face, presented at 200, 500, and 800 ms durations. The high-anxious participants developed the expected attentional bias toward the CS+ at 200 ms presentation time and attentional avoidance at 500 and 800 ms durations. Hypervigilance to aversive stimuli at 200 ms and later avoidance to the same stimuli at 500 and 800 ms were associated with higher levels of galvanic skin conductance to the CS+. The low-anxious individuals developed the opposite attentional pattern with an initial tendency to orient attention away from the aversive stimuli in the 200 ms condition and to orient attention toward aversive stimuli in the remaining time. The differential modulation between hypervigilance and avoidance elicited in the two groups by the conditioning procedure suggests that vulnerability to anxiety is characterized by a latent relationship between diverse attentional mechanisms. Within this relationship, hypervigilance and avoidance to threat operate at different stages of information processing suggesting fuzzy boundaries between early reactive and later-strategic processing of threat.     

状态焦虑对时距知觉的影响：认知评价和注意偏向有调节的中介作用

探讨状态焦虑对时距知觉的影响以及注意偏向与认知评价在其中的中介和调节作用。招募大学生60人, 随机分为高、低状态焦虑组, 用情绪诱导程序诱导高、低状态焦虑; 用点探测范式测量注意偏向; 用时间再现任务测量时距知觉; 用视觉模拟心境量表测量认知评价。结果发现：(1)状态焦虑会导致对2000 ms时距的高估; (2)注意偏向在状态焦虑对2000 ms时距知觉的影响中具有部分中介作用; (3)状态焦虑通过注意偏向影响时距知觉的中介过程受到认知评价的调节作用：只有当认知评价得分较高时, 即个体认为焦虑对心理健康有害程度较高时, 状态焦虑通过注意偏向影响2000 ms时距知觉。研究结果揭示了焦虑个体时距知觉的内部过程, 丰富了焦虑通过注意偏向影响时距知觉的解释视角, 为通过认知评价和注意偏向的调整改善焦虑个体时距偏差现象提供了重要参考。