Interpretation of ambiguous social scenarios in social phobia and depression: evidence from event-related brain potentials

In the current study, event-related potentials (ERPs) and behavioral responses were measured in individuals meeting diagnostic criteria for social phobia, depression, their combination, or neither in order to examine the unique and combined effects of social phobia and depression on the interpretation of ambiguous social scenarios. ERPs revealed a lack of positive interpretation bias and some suggestion of a negative bias in the semantic expectancy N4 component across all clinical groups. Furthermore, socially phobic and comorbid individuals showed reductions in baseline attention allocation to the task, as indexed by P6 amplitude. RT and accuracy likewise revealed a lack of positive interpretation bias across disordered groups. When considered on a continuum across all samples, social phobia and depression symptoms were related to the N4 interpretation bias effect whereas P6 amplitude reduction and RT interpretation bias appeared uniquely associated with social phobia.     

The N2pc component reliably captures attentional bias in social anxiety

We systematically compared different measures of attentional bias (i.e., reaction times, the N2pc component in the EEG, and explicit stimulus ratings) on their ability to reveal attentional engagement to threatening versus neutral facial stimuli in a Dot Probe Task and tested their relation to trait measures of general and social anxiety. We found that the N2pc component reflects a bias toward angry faces with excellent internal consistency. Similar results were obtained for explicit ratings. Reaction time (RT) differences, however, were not indicative of attentional biases and showed zero odd‐even reliability. We further found that both higher (i.e., more negative) N2pc amplitudes and earlier peak latencies were associated with more severe symptoms of social anxiety even when controlling for general trait anxiety. The explicit rating biases were also specifically associated with social anxiety. Conversely, the RT bias was not related to social anxiety levels but to general trait anxiety. This highlights the importance of valid and reliable outcome measures for interventions such as attentional bias modification protocols. Mutual exclusivity of different bias operationalizations is discussed.     

Long-term physical exercise and somatosensory event-related potentials

We have compared the occurrence patterns of somatosensory event-related potentials (ERPs) in athletes (soccer players) and non-athletes. ERPs were elicited by two oddball tasks following separate somatosensory stimulation at the median nerve (upper-limb task) and at the tibial nerve (lower-limb task). In the athlete group the N140 amplitudes were larger during upper- and lower-limb tasks and the P300 amplitude and latency were larger and shorter, respectively, during the lower-limb task compared with non-athletes. On the other hand, no significant differences in the P300 amplitude and latency during the upper-limb task were observed between the athlete and non-athlete groups. These results indicate that plastic changes in somatosensory processing might be induced by performing physical exercises that require attention and skilled movements.     

Auditory and somatosensory event-related brain potentials in early blind humans

Previous event-related potential (ERP) studies have suggested a possible participation of the visual cortex of the blind in auditory processing. In the present study, somatosensory and auditory ERPs of blind and sighted subjects were recorded when subjects were instructed to attend to stimuli of one modality and to ignore those of the other. Both modalities were stimulated with frequent (standard) and infrequent (deviant) stimuli, which differed from one another in their spatial locus of origin. In the sighted, deviant stimuli of the attended modality elicited N2 type of deflections (auditory N2b and somatosensory N250) over the lateral scalp areas. In contrast, in the blind, these ERP components were centroposteriorly distributed, suggesting an involvement of posterior brain areas in auditory and somatosensory stimulus discrimination. In addition, the mismatch negativity, elicited by deviant auditory stimuli even when the somatosensory stimuli were attended, was larger in the blind than in the sighted. This appears to indicate enhanced automatic processing of auditory stimulus changes in the blind. Thus, the present data suggest several compensatory changes in both auditory and somatosensory modalities after the onset of early visual deprivation.     

Attentional focus in social anxiety disorder: potential for interactive processes

The two preeminent cognitive behavioral models of social anxiety [Clark, D.M., & Wells, A., (1995). A cognitive model of social phobia. In Heimberg, R.G., Liebowitz, M., Hope, D.A., and Schneier, F.R. (Eds.), Social phobia: Diagnosis, assessment and treatment (pp. 69–93). New York: Guilford Press.; Rapee, R.M., & Heimberg, R.G., (1997). A cognitive behavioral model of anxiety in social phobia. Behaviour Research and Therapy, 35, 741–756.] suggest that attention to threat stimuli is critical in the maintenance of social fear. However, Clark and Wells assert that socially anxious persons attend almost exclusively to negative thoughts and self-imagery during social situations, whereas Rapee and Heimberg contend that socially anxious persons simultaneously attend to these internal cues and external stimuli potentially indicative of negative evaluation, such as an audience member's facial expressions. Rapee and Heimberg further suggest that attention to external and internal cues during social situations should be interdependent, such that focus on one has causal implications for the experience of the other. The current review examines the nature of the literature as it supports the assertions of each of these models of social anxiety, with particular attention to differing predictions regarding attentional focus. We conclude that socially anxious persons engage in both internal and external focus throughout the course of a social situation; however, there are a number of significant limitations to the literature. Accordingly, directions for future research are considered.     

Early frontal responses elicited by physical threat words in an emotional Stroop task: Modulation by anxiety sensitivity

High-density brain electrical activity elicited by physical threat, positive and neutral words were recorded in 33 healthy individuals screened for high or low anxiety sensitivity (AS) during a modified emotional Stroop task. The paradigm allowed the separate assessment of block and mixed-trial effects. In the block analysis, a significant emotional RT slowing was observed along with the modulation of a frontocentral negativity (350-400 ms) in the high AS group only. In contrast, the mixed-trial analysis revealed a positive enhancement of the ERP to threat words peaking earlier (200-300 ms) over anterior frontal scalp in the absence of RT slowing. This component was preceded by a very early positive modulation (peaking 50 ms) in the high AS group only. It is concluded that frontal ERPs to physical threat words can distinguish the contribution of emotional conflict and emotional salience, particularly in individuals with high trait-anxiety.     

An event-related potential study of supramodal attentional control and crossmodal attention effects

We conducted two audiovisual experiments to determine whether event-related potential (ERP) components elicited by attention-directing cues reflect supramodal attentional control. Symbolic visual cues were used to direct attention prior to auditory targets in Experiment 1, and symbolic auditory cues were used to direct attention prior to visual targets in Experiment 2. Different patterns of cue ERPs were found in the two experiments. A frontal negativity called the ADAN was absent in Experiment 2, which indicates that this component does not reflect supramodal attentional control. A posterior positivity called the LDAP was observed in both experiments but was focused more posteriorly over the occipital scalp in Experiment 2. This component appears to reflect multiple processes, including visual processes involved in location marking and target preparation as well as supramodal processes involved in attentional control.     

Adaptive control of event integration: evidence from event-related potentials

We investigated whether it is possible to control the temporal window of attention used to rapidly integrate visual information. To study the underlying neural mechanisms, we recorded ERPs in an attentional blink task, known to elicit Lag-1 sparing. Lag-1 sparing fosters joint integration of the two targets, evidenced by increased order errors. Short versus long integration windows were induced by showing participants mostly fast or slow stimuli. Participants expecting slow speed used a longer integration window, increasing joint integration. Difference waves showed an early (200 ms post-T2) negative and a late positive modulation (390 ms) in the fast group, but not in the slow group. The modulations suggest the creation of a separate event for T2, which is not needed in the slow group, where targets were often jointly integrated. This suggests that attention can be guided by global expectations of presentation speed within tens of milliseconds.     

Autobiographical memory biases in social anxiety

Individuals with social anxiety preferentially attend to threatening social information during and following social events. As such, cognitive models predict that social anxiety should be associated with biases in the recall of social events. However, initial experimental studies examining this assumption either failed to find such biases or found only weak evidence for an autobiographical memory bias. The current review examines an emerging line of evidence offering support for the role of an autobiographical memory bias in the development and maintenance of social anxiety. The review begins by examining current theoretical approaches to autobiographical memory before looking at empirical studies that have examined differences between socially anxious and non-anxious individuals in the recall of autobiographical memories. Specific memory biases include properties of social-threat memories, the imagery associated with these memories, and the cognitive processing styles that have been found to either facilitate or inhibit the recall of emotional memories. Limitations in methodologies used to study retrieval of memories and the implications of findings for future research are discussed.     

Early posterior ERP components do not reflect the control of attentional shifts toward expected peripheral events

Previous experiments investigating ERP correlates of anticipatory attention shifts triggered by central symbolic cues have identified a contralateral "early directing attention negativity," which was assumed to be generated by processes involved in the control of spatial orienting. Here we demonstrate that this component is not directly linked to the control of attentional shifts, but instead reflects the selection of task-relevant aspects of cue stimuli. In contrast, later ERP components triggered during covert attentional shifts are insensitive to physical cue attributes, and thus appear to be genuine electrophysiological correlates of covert attentional control mechanisms.     

Face processing biases in social anxiety: an electrophysiological study

Studies of information processing biases in social anxiety suggest abnormal processing of negative and positive social stimuli. To further investigate these biases, behavioral performance and event-related brain potentials (ERPs) were measured, while high- and low-socially anxious individuals performed a modified version of the Erikson flanker task comprised of negative and positive facial expressions. While no group differences emerged on behavioral measures, ERP results revealed the presence of a negative face bias in socially anxious subjects as indexed by the parietally maximal attention- and memory-related P3/late positive potential. Additionally, non-anxious subjects evidenced the presence of a positive face bias as reflected in the centrally maximal early attention- and emotion-modulated P2 and the frontally maximal response monitoring-related correct response negativity. These results demonstrate the sensitivity of different processing stages to different biases in high- versus low-socially anxious individuals that may prove important in advancing models of anxious pathology.     

视听联合刺激诱发事件相关电位的时变源分析

目的 运用偶极子源分析方法分析视（V）、听（A）单独刺激和视听（VA）联合刺激早期阶段脑功能区的动态变化.方法 采用64道脑电采集系统,记录14例志愿者在视觉、听觉和视听联合刺激下诱发的事件相关电位（ERPs）,并将这3种任务的早期阶段分成不同子时间段进行偶极子源分析.结果 视觉、听觉刺激诱发的早期偶极子源定位在特定脑皮层功能区,并且偶极子的位置和强度随时间发生变化.结论 脑功能区在视听刺激的早期阶段（＜150 ms）对感觉信息存在动态的处理过程.     

Effects of ISI and stimulus probability on event-related go/nogo potentials after somatosensory stimulation

The present study investigated the characteristics of the middle-latency negative potential of event-related potentials (ERPs) using somatosensory go/nogo tasks. We manipulated interstimulus interval (ISI) in Experiment 1 and stimulus probability in Experiment 2 and analyzed the subtracted difference waveform resulting from subtraction of the ERP evoked by the go stimulation from that evoked by the nogo stimulation. In Experiment 1, the peak latency of negativity became significantly longer as the ISI increased, but the peak amplitude was unchanged. The reaction time (RT) was longer with increasing ISI. In Experiment 2, manipulation of the stimulus probability yielded an increase in peak amplitude with decreasing probability of the nogo stimulus, but did not affect the latency. The RT increased as the probability of a nogo stimulus rose. Because manipulation of the ISI and stimulus probability elicited different brain activities, we hypothesized that manipulation of the ISI elicited a delay of the stimulus evaluation process including response inhibition, and that stimulus probability significantly affected the strength of the response inhibition process.     

Negativity bias of the self across time: An event-related potentials study

To investigate the neural basis of self-evaluation across time as a function of emotional valence, event-related potentials were recorded among participants instructed to make self-reference judgments when evaluating their past, present and future selves. Results showed that, when evaluating present and past selves, negative words elicited a more positive ERP deflection in the time window between 650 ms and 800 ms (LPC) relative to positive words. However, when evaluating the future selves, there was no significant difference on the amplitude of the LPC evoked by negative versus positive words. Findings provided evidence for the effect of emotional valence on the self across time at a neurophysiological level and identified the time course of negative bias in the temporal self. More specifically, people were inclined to be relatively less negative and optimistic about their future self but had mixed emotions about past and present selves.     

Time course of attentional bias in social anxiety: The effects of spatial frequencies and individual threats

Hypervigilance and attentional bias to threat faces with low-spatial-frequency (LSF) information have been found in individuals with social anxiety. The vigilance–avoidance hypothesis posits that socially anxious individuals exhibit initial vigilance and later avoidance to threatening cues. However, the temporal dynamics of these two processes in response to various LSF threats in social anxiety remain unclear. In the current study, we presented faces containing anger, disgust, and fear in high and low spatial frequencies and compared the neural correlates with sensory perception and attention in individuals with high versus low social anxiety (HSA/LSA, n = 24). A visual search task was used to investigate the attentional effects of threats and spatial frequencies, and event-related potentials, particularly, the visual components of P1 and P250, were measured to index visual perceptual and attentional processes, respectively. We found that HSA individuals showed pronounced P1 and reduced P250 to LSF (vs. HSF) faces, regardless of emotion type, suggesting a general pattern of initial vigilance and later avoidance to LSF faces in social anxiety. Furthermore, while LSA individuals showed enhanced P250 to both fear and disgust (vs. neutral) faces, HSA individuals showed pronounced P250 to disgust faces alone. Our results, thus, elucidate the temporal profile of early vigilance and later avoidance in social anxiety, highlighting its broad implication for all faces and predominance in the low spatial frequency. Considering individual threats, our results demonstrate specific attentional avoidance of fear faces in social anxiety.     

How experience shapes memory for faces: An event-related potential study on the own-age bias

Young adults more accurately remember own-age than older faces. We tested whether this own-age bias (OAB) is reduced by increased experience. Young experts (geriatric nurses) and controls performed a recognition experiment with young and old faces. Critically, while control participants demonstrated better memory for young faces, no OAB was observed in the experts. Event-related potentials revealed larger N170 and P2 amplitudes for young than old faces in both groups, suggesting no group differences during early perceptual processing. At test, N250 repetition effects were more anteriorily distributed for own- than other-age faces in control participants, whereas experts showed no corresponding effects. A larger late positive component (LPC) for old than young faces was observed in controls, but not in experts. Larger LPCs may reflect prolonged stimulus processing compromising memory retrieval. In sum, experience with other-age faces does not affect early perceptual processing, but modulates later stages related to memory retrieval.     

Crossmodal links in spatial attention are mediated by supramodal control processes: evidence from event-related potentials

Crossmodal links in spatial attention were studied in an experiment where participants had to detect peripheral tactile or visual targets on the attended side, while ignoring all stimuli on the unattended side and in the currently irrelevant modality. Both relevant locations and relevant modalities were specified on a trial-by-trial basis by auditory precues. Spatial orienting in the cue-target interval was reflected in anterior negativities and occipital positivities contralateral to the cued side, either when vision or touch was cued as relevant. These effects resembled previously reported ERP modulations during shifts of visual attention, implicating supramodal mechanisms in the control of spatial attention and demonstrating their independence of cue modality. Early effects of spatial attention on somatosensory and visual ERPs were of equivalent size for currently relevant and irrelevant modalities. Results support the idea that crossmodal links in spatial attention are mediated by supramodal control mechanisms.     

Circadian rhythm and desensitization in chemosensory event-related potentials in response to odorous and painful stimuli

Olfactory (H2S) and trigeminal (CO2) event-related potentials (ERPs) were studied with respect to circadian rhythm and desensitization. ERPs, perceived odor and pain intensity, oral temperature, blood pressure, heart rate, nasal volume, and sleepiness were assessed four times at 04:00, 08:00, 12:00, 16:00, 20:00, and 24:00 hr in five young men. For each of these 24 sessions per participant, H2S and CO2 were each presented in 15 series of five stimuli with a 5-s ISI within and 30-s ISI between series. ERP amplitudes, but not latencies, followed a circadian rhythm (largest at 16:00 and smallest at 04:00) similar to oral temperature and opposite to sleepiness. Amplitudes decreased (most pronounced at 16:00 and 20:00) and latencies increased with repeated stimulation, suggesting desensitization, in accordance with odor and pain intensity. These findings imply that circadian rhythm and desensitization should be considered in chemosensory ERP studies.     

Mechanisms of attentional biases towards threat in anxiety disorders: An integrative review

A wealth of research demonstrates attentional biases toward threat in the anxiety disorders. Several models have been advanced to explain these biases in anxiety, yet the mechanisms comprising and mediating the biases remain unclear. In the present article, we review evidence regarding the mechanisms of attentional biases through careful examination of the components of attentional bias, the mechanisms underlying these components, and the stage of information processing during which the biases occur. Facilitated attention, difficulty in disengagement, and attentional avoidance comprise the components of attentional bias. A threat detection mechanism likely underlies facilitated attention, a process that may be neurally centered around the amygdala. Attentional control ability likely underlies difficulty in disengagement, emotion regulation goals likely underlie attentional avoidance, and both of these processes may be neurally centered around prefrontal cortex functioning. The threat detection mechanism may be a mostly automatic process, attentional avoidance may be a mostly strategic process, and difficulty in disengagement may be a mixture of automatic and strategic processing. Recommendations for future research are discussed.     

Cortisol-induced enhancement of emotional face processing in social phobia depends on symptom severity and motivational context

We investigated the effects of cortisol administration on approach and avoidance tendencies in 20 patients with social anxiety disorder (SAD). Event-related brain potentials (ERPs) were measured during a reaction time task, in which patients evaluated the emotional expression of photographs of happy and angry faces by making an approaching (flexion) or avoiding (extension) arm movement. Patients showed significant avoidance tendencies for angry but not for happy faces, both in the placebo and cortisol condition. Moreover, ERP analyses showed a significant interaction of condition by severity of social anxiety on early positive (P150) amplitudes during avoidance compared to approach, indicating that cortisol increases early processing of social stimuli (in particular angry faces) during avoidance. This result replicates previous findings from a non-clinical sample of high anxious individuals and demonstrates their relevance for clinical SAD. Apparently the cortisol-induced increase in processing of angry faces in SAD depends on symptom severity and motivational context.