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

Effects of attention bias modification for anxiety: Neurophysiological indices and moderation by symptom severity

OBJECTIVE

Attention bias modification (ABM) aims to decrease anxiety symptom severity through the reduction of threat-related attention bias (AB). Individual differences in treatment response and poor measurement reliability of AB have called its clinical promise into question. The current study examined whether individual differences in anxiety severity at baseline moderated treatment response, and employed both behavioral and neurophysiological metrics of AB.

METHODS

Participants (N = 99) were randomly assigned to four weeks of ABM or placebo control training (PT). Self-reported anxiety symptom severity, and AB metrics and ERPs generated during the dot probe task were collected at baseline (Time 1), one-week post-intervention (Time 5), and at a three-month follow-up (Time 6).

RESULTS

ABM, relative to PT, reduced ERPs indexing attention discrimination (N170) and increased ERPs indexing salience tracking (P3). Increases in P3 were associated with ABM-related reductions in anxiety. Anxiety severity was reduced following ABM, but only among those with higher baseline anxiety symptom severity.

CONCLUSIONS

ABM effectively reduced symptom severity among those with higher levels of anxiety, and modulated neurophysiological indices of AB.

SIGNIFICANCE

Results provide evidence for attention-relevant ERPs as outcomes of ABM treatment responsivity and suggest that ABM may be most beneficial for those with more severe anxiety symptoms.

Spatial attentional biases toward height-related words in young males with physical stature dissatisfaction

By recording event-related potentials (ERPs) during a dot-probe task, the present study examined the neural dynamics of attentional bias toward height-related words among height dissatisfied males. Sixty male participants screened by Negative Physical Self Scale-Stature Concerns subscale (NPS-S) were assigned into a high height dissatisfaction (HHD) group and a low height dissatisfaction (LHD) group. The results showed that tall-related versus neutral words elicited larger N2pc for both HHD and LHD groups, whereas short-related versus neutral words elicited larger N2pc only for the HHD group. Additionally, an evident Pd was elicited by tall-related words for the HHD group, but not for the LHD group. Taken together, these findings revealed attentional biases toward height-related information for HHD individuals on a neural level. Specifically, HHD individuals showed an enhanced spatial attention oriented toward both tall-related and short-related words, and then, the allocated attention to the tall-related words was terminated by an active suppression mechanism.

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.

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.

Rapid processing of fearful faces relies on the right amygdala: evidence from individuals undergoing unilateral temporal lobectomy

Facial expressions of emotions have been shown to modulate early ERP components, in particular the N170. The underlying anatomical structure producing these early effects are unclear. In this study, we examined the N170 enhancement for fearful expressions in healthy controls as well as epileptic patients after unilateral left or right amygdala resection. We observed a greater N170 for fearful faces in healthy participants as well as in individuals with left amygdala resections. By contrast, the effect was not observed in patients who had undergone surgery in which the right amygdala had been removed. This result demonstrates that the amygdala produces an early brain response to fearful faces. This early response relies specifically on the right amygdala and occurs at around 170 ms. It is likely that such increases are due to a heightened response of the extrastriate cortex that occurs through rapid amygdalofugal projections to the visual areas.