The Cognitive And Neural Correlates Of Inhibition In Trait Anxiety

Trait anxiety, a vulnerable personality factor for anxiety disorders and depression, is defined as an individual’s disposition to experience frequent and intense anxiety and worry in response to various stress situations. High levels of trait anxiety confer elevated risk for the development of anxiety and other psychiatric disorders. Although a large number of studies suggest that trait anxiety is associated with impaired inhibition of threat distractors, recent studies have been demonstrating that this impairment of inhibition can even be observed in the absence of threat. On the basis of the common assumption that the general cognitive control is impaired in individuals with HTA, two major predictions have been put forward concerning the underlying mechanisms of this impairment. On the one hand, the attentional control theory of trait anxiety expected that HTA individuals may show greater recruitment of top-down resources to compensate their reduced processing efficiency and to maintain the same levels of task performance as low anxious individuals. On the other hand, Bishop (2009) argued that trait anxiety is linked to impoverished recruitment of top-down resources to inhibit neutral distractors. The present study thus evaluated the two competing predictions in several experimental paradigms to elaborate the neuro-cognition of inhibition in trait anxiety, by means of event-related potentials with high high time-resolution. We foused on how trait anxiey influences inhibition which is sub-components of attention control. According to Friedman and Miyake (2004) the inhibition function of the central executive involves at least two components:prepotent response inhibition and resistance to interference from distracters (cognitive inhibition). The first two experiments investigated the neural correlates of response inhibition in trait anxiety, and two extra experiments investigated the neural correlates of cognitive inhibition in trait anxiety.The first study is the first to utilize a dual-task design with event-related potentials (ERPs) to investigate how WM load modulates distractor processing in trait anxiety. Attentional control theory posits that trait anxiety is associated with a general deficit in inhibition of task-irrelevant information, whereas Load theory of attention proposes that a high working memory (WM) load increases the potential for distractors to interfere with cognitive control processes. However, the influence of WM load on distractor processing in trait anxiety has not been explored thoroughly. Here, this question was investigated using a dual-task design in combination with event-related potentials. Female participants were required to remember either one (low WM load) or six letters (high WM load) while performing a flanker task. Our results showed that a high WM load disrupted participants’ performance in incongruent trials and this effect was exacerbated for the high trait-anxious (HTA) group. This exacerbation was reflected by delayed reaction times (RTs) and more negative N2amplitudes in incongruent trials for the HTA group relative to the low trait-anxious group under high WM load. Both groups, however, did not differ in their ability to inhibit task-irrelevant distractors under low WM load in either behavioral or neural terms. Furthermore, when WM load was high, trait anxiety levels of HTA individuals correlated with interference effects on RTs and N2amplitudes, respectively. Our results document that trait anxiety is associated with less efficient recruitment of top-down mechanisms required for the inhibition of distractors when limited WM resources are depleted by high WM load. We suggest that WM load should be taken into consideration in studies investigating attentional control deficits in trait anxiety.The second study investigated the neural dynamics of conflict adaptation in trait anxiety in a color-naming Stroop task using ERPs. Conflict monitoring and resolution can be measured by examining conflict adaptation, the dynamical adjustment of cognitive control based on previous-trial conflict. For ERPs, individuals with low trait-anxious (LTA) showed larger conflict slow potential (SP) amplitudes for incongruent (high-conflict) trials following congruent (low-conflict) trials relative to incongruent trials following incongruent trials. Importantly, individuals with HTA showed no such differences in conflict SP amplitudes after previous-trial conflict; however, they showed larger N450amplitudes for incongruent trials following congruent trials relative to incongruent trials following incongruent trials. These results suggest that individuals with HTA are associated with hyperactive conflict-detection mechanism and impairments in recruitment of cognitive resources after previous conflict to solve current conflict. Thus, our finding support impoverished recruitment of top-down resources in trait anxiety rather than ACT expected compensatory and greater recruitment of top-down resources in trait anxiety. Our finding extends recent observations implying an important role of individual difference in personality in regulating conflict-driven cognitive control.In the third study, we present a research on the manifestation of general inefficient filtering of neutral distractors during visual—spatial WM maintenance stages in HTA individuals. Research has indicated that highly trait-anxious (HTA) individuals exhibit a specific deficit in filtering threat-related distractors from visual-spatial working memory (WM). Prior demonstrations of impaired inhibition control in HTA individuals have mainly focused on tasks that required the inhibition of prepotent response tendencies. Studies on the suppression of emotionally neutral distractors from WM in trait anxiety have also been minimal. Female participants performed a visual—spatial WM task while ERPs were recorded. They were made to remember the orientations of red rectangles within half of the screen and to ignore all salient green rectangles. As predicted, no significant main effect of group and no interaction between group and condition were found in the N2pc component, suggesting that group differences did not manifest in the initial process of object individuation. During the subsequent WM maintenance phase, HTA individuals were highly inefficient at filtering the irrelevant items from WM, as reflected not only by parallel late contralateral delay activity (CDA;450to900ms) amplitudes for the distractor condition and the four red items, but also by a smaller filtering efficiency score in the HTA group than in the low-trait-anxiety group. Extending previous studies, our findings verify a general filtering impairment in HTA individuals for task-irrelevant salient distractors during a WM maintenance phase.The fouth study examined anxiety-related group differences in neural activity associated with the amount of representations in visual-spatial working memory (WM), using the ERPs in a lateralized change detection task. CDA was proposed as a neural marker of the amount of representations in visual WM. Different levels of memory load were varied within each block. Despite unimpaired behavioral performance in individuals with high trait-anxious (HTA), they displayed several changes in the neuronal markers of the memory processes. The CDA amplitude reached asymptote at loads of three and four objects for HTA and low trait-anxious (LTA) individuals, respectively. This result indicates that HTA individuals reach the upper limit of representation capacity with a smaller memory load than LTA individuals. For individuals with HTA, the smaller CD A for higher loads could be attributed to less contralateral cortical activity, which further supports their reduced representations of items in WM.