The influence of self-relevant materials on working memory in dysphoric undergraduates

A human working memory advantage for social network information

As a social species, humans live in complexly bounded social groups. In order to navigate these networks, humans rely on a set of social-cognitive processes, including social working memory. Here, we designed a novel network memory task to study working memory for social versus non-social network information across 241 participants (18-65 years) in a tightly controlled, preregistered study. We show that humans demonstrate a working memory advantage for social, relative to non-social, network information. We also observed a self-relevant positivity bias, but an 'other' negativity bias. These findings are interpreted in the context of an evolutionary need to belong to one's social group, to identify risks to one's social safety and to appropriately track one's social status within a complex network of social relationships.

Distinct Effects of Anxiety and Depression on Updating Emotional Information in Working Memory

Anxiety and depression have been shown to negatively influence the processing of emotional information in working memory. However, most studies have examined anxiety-related or depression-related working memory deficits independently, without considering their high co-morbidity. We tested the effects of emotional valence on working memory performance among healthy young adults with varying levels of anxiety and depressive symptoms. Ninety young adults aged between 18-24 (51 female) completed an emotional 2-back task in which positive, negative, and neutral images were presented. Multi-level modeling was used to examine anxiety and depressive symptoms as predictors of response accuracy and latency across the three emotional valence conditions. The results showed that participants responded to negative images with the highest accuracy and to positive images with the lowest accuracy. Both negative and positive images elicited slower responses than neutral images. Importantly, we found that more severe anxiety symptoms predicted a smaller difference in response accuracy between negative and neutral stimuli, whereas more severe depressive symptoms predicted a larger updating reaction time difference between positive and neutral stimuli. These findings demonstrated the uniquely anxiety-related deficits in processing negative contents and the uniquely depression-related deficits in updating positive contents in working memory, thus highlighting the necessity of novel cognitive bias modification interventions targeting the anxiety-specific and depression-specific deficits in working memory.

Interaction between working memory load and the ability to resist interference from negative distractors in dysphoria

Although the relationship between emotional working memory (WM) and depressive symptoms has been well established in clinical samples, research in the subclinical population has produced mixed results. The present study tested the effect of WM load on control of interference from emotional (positive, negative, neutral) distractors in dysphoria. Dysphoric (n = 32) and non-dysphoric (n = 35) university students were administered the emotional 2-back (lower WM load) and 3-back (higher WM load) tasks. Results showed that resisting negative distractors was more difficult for the dysphoric group than the non-dysphoric group, but only in the 3-back task. The results demonstrate that dysphoria is associated with greater interference from negative distractors under high WM load. We conclude that both WM load and emotional valence have an effect on WM performance in dysphoria, and the poor ability to resist interference from negative distractors in WM might be a key cognitive vulnerability factor for depression.

Cognitive Control and Ruminative Responses to Stress: Understanding the Different Facets of Cognitive Control

Rumination has been linked to the onset and course of depression. Theoretical models and empirical evidence suggest that deficits controlling negative material in working memory underlie rumination. However, we do not know which component of cognitive control (inhibition, shifting, or updating) contributes most to rumination, and whether different components predict the more maladaptive (brooding) versus the more adaptive (reflection) forms of rumination. We aimed to advance theory and research by examining the contribution of different facets of cognitive control to the level and trajectory of brooding and reflection. At baseline, participants completed three cognitive tasks that assessed their inhibition, shifting, and updating biases, respectively. Next, using experience sampling methodology, participants rated their level of rumination and negative affect nine times during the 48 h after their most stressful exam. At each time point, higher levels of brooding, but not reflection, predicted higher levels of negative affect at the next time point. Furthermore, several facets of shifting and inhibition, but not updating, predicted brooding immediately after the exam and its trajectory of change over 48 h. Additionally, difficulty inhibiting neutral words predicted both brooding and reflection. These findings inform theoretical models describing the role of cognitive control in brooding and reflection.

Increased neural sensitivity to self-relevant stimuli in major depressive disorder

The current research examined how individuals with depression process emotional, self-relevant stimuli. Across two studies, individuals with depression and healthy controls read stimuli that varied in self-relevance while EEG data were recorded. We examined the late positive potential (LPP), an ERP component that captures the dynamic allocation of attention to motivationally salient stimuli. In Study 1, participants read single words in a passive-viewing task. Participants viewed negative, positive, or neutral words that were either normative or self-generated. Exploratory analyses indicated that participants with depression exhibited affective modulation of the LPP for self-generated stimuli only (both positive and negative) and not for normative stimuli; healthy controls exhibited similar affective modulation of the LPP for both self-relevant and normative stimuli. In Study 2, using a separate sample and a different task, stimuli were provided within the context of sentence stems referring to the self or other people. Participants with depression were more likely to endorse negative self-referent sentences and reject positive ones compared to healthy controls. Depressed participants also exhibited an increased LPP to negative stimuli compared to positive or neutral stimuli. Together, these two studies suggest that depression is characterized by relatively increased sensitivity to affective self-relevant stimuli, perhaps in the context of a broader reduction in emotional reactivity to stimuli that are not self-relevant. Thus, depression may be characterized by a more nuanced pattern based on the degree of stimulus self-relevance than either a global decrease or increase in reactivity to affective stimuli.

Attentional bias modification reduces clinical depression and enhances attention toward happiness

Difficulty in clinical antidepressant treatment leads to the pursuit of alternative treatments, such as cognitive-behavior therapy (CBT). CBT combined with regular antidepressants have indicated an optimal therapeutic effect in clinic. Attentional bias is important in the occurrence and remission of depression, however, few studies have explored the effect of attentional bias modification (ABM) on depression, and inconsistent results have been obtained due to the heterogeneity in the targeted populations, training tasks, strategies, and materials. Hence, the current study aimed to explore the therapeutic effect of ABM on depression in clinical depression. Study I was designed to explore the optimal training methods regarding task (dot-probe vs. cue-target), material (faces vs. self-referent words), and strategy (mixed ABM toward positive and away from negative stimuli vs. positive ABM toward positive stimuli) in unselected undergraduates once daily for 10 days (N = 309). Study II was carried out to observe the effect of 10 days ABM toward positive and away from negative faces (based on Study I) on clinical depression (N = 32). Depression level was assessed via a self-reporting questionnaire and a structured interview, while attentional bias was tested by cue-target task and attention to positive and negative inventory (APNI). In unselected undergraduates (Study I), two strategies significantly reduced the self-reporting depression scores: mixed ABM toward positive stimuli and away from negative stimuli with emotional faces, and positive ABM toward positive materials only with self-referent words. In patients with major depressive disorder (MDD) (Study II), the mixed ABM with emotional faces resulted in enhanced attentional bias toward happy materials in the cue-target task and APNI, which predicted a delayed depression reduction in clinical depression at the one-month follow-up investigation. Our finding confirms the literature and broadens the knowledge with the evidence of the optimal therapeutic effect of ABM combined with regular antidepressants in clinical depression. The findings that a quick enhancement in positive attentional bias, predicting a later therapeutic effect on clinical depression reduction, indicate a potential mechanism that could underlie the therapeutic process of ABM in depression. The findings that two training strategies are effective in depression reduction suggest that different strategies should be utilized to treat different types of depression. This study offers a potential way to cure depression and could be further practiced in clinic.