Updating emotional content in working memory: a depression-specific deficit?

Association between the performance of executive function and the remission of depressive state after clinical treatment in patients with depression

BACKGROUND

Previous studies have reported that patients with depression have significant cognitive impairment. The aim of this study is to comprehensively evaluate the impairment of executive functions in patients with depression and whether the cognitive behavior performance of executive function is association with remission of depressive state after clinical treatment.

METHODS

We used cognitive-behavioral test to evaluate the performance of executive functions of 95 inpatients with depression before hospitalization and conducted two follow-up evaluations of their depression status on the 15th day of hospitalization and approximately 9 months after discharge.

RESULTS

The performance of executive function except the accuracy of inhibition control in patients with depression were significantly worse than that of healthy controls. Multivariate linear regression analysis found that the reaction time of working memory not only had a significant linear relationship with the baseline depression scores of patients with depression, but also had a significant linear relationship with the reduced depression scores after two follow-up visits.

LIMITATIONS

We only used cognitive-behavioral data as indicators to evaluate the cognitive performances of participants and only measured three components of executive function.

CONCLUSIONS

The reaction time of working memory was a stable and effective predictor of symptom relief in patients with depression after clinical treatment. These results provide initial evidence for working memory to predict the clinical prognosis of inpatients with depression prospectively, which could be further leveraged to improve intervention approaches and analyze the heterogeneity of depression.

The Cognitive Cost of Repetitive Thinking: A Study on the Effects of Shifting and Updating on Rumination of Emotional Experiences

The present study aimed to investigate the consequence of resource competition between post-emotional processing and concurrent cognitive tasks. Previous studies have shown that such a resource competition engenders both short-term (e.g., defeats in the execution of the working memory task) and long-term effects (e.g., procrastination or rumination following an emotional experience). We expected these effects to vary as a function of the different WM components involved (shifting, Study 1; updating, Study 2). In two studies, participants (Study 1: N = 48; Study 2: N = 42) were administered one out of two variants of a visuospatial task (Study 1: shifting; Study 2: updating) adopted by Curci and colleagues before and after a negative or neutral manipulation. Rumination was assessed immediately after the second WM task performance and 24 h later. In Study 1, results showed that the exposure to negative content impaired the subsequent executive performance compared with exposure to neutral material, while no difference was found in Study 2. Rumination for emotional material was higher and more persistent over time as a function of shifting resources but not for updating ones. These findings provide information on the possible role of individuals' cognitive resources on rumination for emotional experiences.

"Don't [ruminate], be happy": A cognitive perspective linking depression and anhedonia

Anhedonia, a lack of pleasure in things an individual once enjoyed, and rumination, the process of perseverative and repetitive attention to specific thoughts, are hallmark features of depression. Though these both contribute to the same debilitating disorder, they have often been studied independently and through different theoretical lenses (e.g., biological vs. cognitive). Cognitive theories and research on rumination have largely focused on understanding negative affect in depression with much less focus on the etiology and maintenance of anhedonia. In this paper, we argue that by examining the relation between cognitive constructs and deficits in positive affect, we may better understand anhedonia in depression thereby improving prevention and intervention efforts. We review the extant literature on cognitive deficits in depression and discuss how these dysfunctions may not only lead to sustained negative affect but, importantly, interfere with an ability to attend to social and environmental cues that could restore positive affect. Specifically, we discuss how rumination is associated to deficits in working memory and propose that these deficits in working memory may contribute to anhedonia in depression. We further argue that analytical approaches such as computational modeling are needed to study these questions and, finally, discuss implications for treatment.

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.

Working memory function in patients with major depression disorder: A narrative review

Working memory (WM) deficits are recognized as serious cognitive impairment in patients with major depressive disorder (MDD). This review aims to clarify the effects of impaired WM function in patients with MDD and explore non-invasive and effective treatments that can be adopted in clinical practice. This review (1) synthesizes extant literature examining brain function and brain areas in terms of WM in individuals with depression, (2) utilizes the outcomes of the studies presented in this review to discuss the effects of impaired WM function on cognitive processing in individuals with depression, (3) integrates the treatments explored in current studies and (4) provides some suggestions for future research. We found that (1) central executive (CE) components affect the processing of WM, and this might be one of the factors influencing cognitive biases, as it is implicated in repetitive negative thinking and rumination; (2) the left dorsal anterior cingulate cortex (dACC), the left dorsolateral prefrontal cortex (DLPFC) and the regions of the default mode network (DMN) play a vital role in CE functioning; and (3) psychotherapy, cognitive training, exercise and physical therapy can be used as complementary treatments for MDD.

Aging and distractor resistance in working memory: Does emotional valence matter?

Background

Emotional stimuli used as targets of working memory (WM) tasks can moderate age-related differences in WM performance, showing that aging is associated with reductions in negativity bias. This phenomenon is referred to as the positivity effect. However, there is little research on whether emotional distractors have a similar moderating effect. Moreover, the underlying neural mechanism of this effect has not been studied. In this study, we examined the behavioral and neurophysiological basis for age differences in resistance to emotional distractors within WM.

Methods

Older adults (n = 30, ages 60–74) and young adults (n = 35, ages 19–26) performed a 2-back task in which a digit was superimposed on a face with a happy, angry, or neutral expression as a distractor. Event-related potential (ERP) was simultaneously recorded to assess P2, N2, and later positive potential (LPP) amplitudes.

Results

Older adults were less accurate and slower than young adults on the WM task. Moreover, the results demonstrated a significant interaction between age and emotional valence on response accuracy, young adults' performance was worse when the distractor was neutral or positive than when it was negative, but there was no effect of the emotional valence of distractors on older adults’ WM performance. ERP analyses revealed greater P2 amplitude in older adults than young adults, regardless of the emotional valence of distractors. However, older adults and young adults did not differ on N2 or LPP amplitude, and negative distractors elicited greater N2 than positive distractors in both age groups.

Conclusions

The behavioral findings provided evidence of age-related reductions in negativity bias. Thus, the behavioral measures indicated a positivity effect in WM. However, the ERP results did not show this same interaction. These discrepant results raise questions about whether and to what extent older and young adults differ in controlling the effect of emotional distractors in WM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-022-00953-y.

Cognitive processing of emotional information during menstrual phases in women with and without postpartum depression: differential sensitivity to changes in gonadal steroids

Gonadal steroids (GSs) have been repeatedly shown to play a central role in the onset of postpartum depression (PPD). The underlying mechanisms, however, are only partially understood. We investigated the relationship between cognitive processing of emotional information and naturally occurring hormonal fluctuations in women with and without previous PPD. Euthymic, parous women, with a history (hPPD, n=32) and without a history (nhPPD, n=43) of PPD, were assessed during late-follicular and late-luteal phases. Participants were administered cognitive tasks assessing attention (dot-probe; emotional Stroop), evaluation (self-referential encoding) and incidental recall, and self-report measures. Menstrual-phase-specific differences were found between late-follicular vs. late-luteal phases among hPPD only, with depression-associated patterns observed in the late-luteal phase on the self-referential encoding and incidental recall task and emotional Stroop task, but not on the dot-probe task. No main effect for menstrual phase was found on any of the tasks or questionnaires, apart from the brooding component of rumination. Women with hPPD demonstrate a differential bias in cognitive processing of emotional information that is menstrual phase dependent, and did not correspond to similar difference in mood symptoms. These biases may reflect sensitivity to gonadal steroid fluctuations that are associated with PPD.

Comparing emotional working memory in adolescents and young adults with and without depressive symptoms: developmental and psychopathological differences

Depressive symptoms are associated with working memory impairments. Yet, comparative studies examining working memory across the developmental spectrum in depressed and non depressed cohorts are lacking. This study examined emotional working memory in 74 adolescents (mean age = 14; 21 with depressive symptoms) and 92 adults (mean age = 22; 36 with depressive symptoms). Participants completed two versions of an emotional face n-back task, and either paid attention to the valence of the emotion or the gender. Both tasks were completed at low load (0-back) and high load (2-back). In the high load condition, healthy adolescents showed a bias towards positive faces, both speeding up reaction times (RTs) when emotion was task relevant but slowing RTs when they were task irrelevant. This interaction was neither significant in adolescents with depressive symptoms nor in young adults. Depressive symptoms did not influence RTs in low load. The results indicate that adolescents with depressive symptoms might lack the bias towards positive affective material at high load WM task present in healthy adolescents.

Widowhood Impairs Emotional Cognition Among Elderly

Background

The negative impacts of spousal bereavement on the emotional health of the elderly (e.g., depression and anxiety) have been revealed. However, whether widowhood impairs emotional cognition among the elderly is less known. The purpose of this study is to reveal the emotional cognitive deficits among the widowed elderly.

Methods

In this study, we recruited 44 widowed elderly (WE) and 44 elder couples (non-widowed elderly, NWE) and examined their emotional cognition including attention and visual working memory, which were measured by the visual search task and delayed-match-to-sample task, respectively. Three kinds of emotional faces (i.e., sad, angry, and happy) were adopted as the attentional or mnemonic targets.

Results

It revealed that WE had a general deficit in search efficiency across emotional types, while they showed mnemonic deficits in negative faces but not positive faces. Furthermore, the modeling analysis revealed that the level of depression or state anxiety of the elderly moderated the effects of widowhood on the deficits of mnemonic processing, i.e., the deficits were only evident among WE with the high level of depression or state anxiety.

Conclusion

These findings reveal the attentional deficits in sad, angry, and happy faces and the mnemonic deficits in sad and angry faces among elderly who suffer from widowhood and point out the important role of emotional problems such as depression and state anxiety in modulating these emotional cognitive deficits.

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, Cognitive Biases and Emotion Regulation in Depression: A New Proposal for an Integrative Interplay Model

Research traditions on cognition and depression focus on relatively unconnected aspects of cognitive functioning. On one hand, the neuropsychological perspective has concentrated on cognitive control difficulties as a prominent feature of this condition. On the other hand, the clinical psychology perspective has focused on cognitive biases and repetitive negative patterns of thinking (i.e., rumination) for emotional information. A review of the literature from both fields reveals that difficulties are more evident for mood-congruent materials, suggesting that cognitive control difficulties interact with cognitive biases to hinder cognitive switching, working memory updating, and inhibition of irrelevant information. Connecting research from these two traditions, we propose a novel integrative cognitive model of depression in which the interplay between mood-congruent cognitive control difficulties, cognitive biases, and rumination may ultimately lead to ineffective emotion-regulation strategies to downregulate negative mood and upregulate positive mood.

Cognitive control over emotional information in current and remitted depression

Cognitive theories of depression propose that difficulty exerting cognitive control over emotional information may be involved in the development, maintenance, and/or recurrence of depression. This study evaluated depression-related biases in three cognitive control functions, namely inhibition, working memory updating, and set shifting. Currently depressed (n = 53), remitted depressed (n = 55), and non-clinical control (n = 51) participants completed computer-based paradigms designed to measure inhibition, working memory updating, and set shifting, respectively, involving emotional stimuli. As hypothesized, currently depressed participants exhibited biases in cognitive control over emotional information but did not exhibit broad impairments on a non-emotional measure of cognitive control. Specifically, currently depressed participants showed a reduced ability to inhibit the processing of negative distracting stimuli and to update working memory with emotional information, relative to control participants. Currently depressed participants also had greater difficulty shifting away from an emotion-relevant task set than from an emotion-irrelevant task set, whereas control participants did not show this bias. Remitted depressed participants did not demonstrate similar biases to currently depressed participants.

Behavioral and neural dynamics of cognitive control in the context of rumination

Rumination is a characteristic feature of several clinical disorders (e.g., major depressive disorder, insomnia disorder). Emerging evidence suggests that a reduced flexibility in the balance between proactive and reactive control might be related to trait rumination. This study aimed to investigate the proactive-reactive control balance in the context of trait rumination. In the current study, we investigated behavioral performance and event-related potentials (ERPs) while participants were performing an AX- Continuous Performance Task, to evaluate whether a shift towards more reactive control (i.e., conflict monitoring and resolution) at the expense of proactive control (i.e., maintenance and updating of task-relevant information) is associated with increased trait rumination. Our behavioral results as well as our ERP results did not demonstrate that a shift towards more reactive control at the expense of proactive control was associated with increased trait rumination. Future research is needed to investigate the proactive-reactive control balance in the context of trait rumination. This study is the first to explore the recruitment dynamics of cognitive control using behavioral as well as electrophysiological measures in the context of rumination.

The emotion regulation effect of cognitive control is related to depressive state through the mediation of rumination: An ERP study

Deficits in cognitive control have been found in depression, but how they contribute to depressive symptoms remains unknown. The present study investigated whether the regulatory efficacy of cognitive control on negative emotion varies with depression level and whether the regulatory efficacy affects depressive symptoms via the mediation of rumination. Fifty participants screened by the Zung Self-Rating Depressive Scale (SDS) with high and low depression levels were selected. They were instructed to controlled-process different semantic representations of aversive pictures, and the amplitude of the late positive potential (LPP) evoked by the pictures was used as the measure of electrocortical response. We found that controlled-processing neutral representations of aversive pictures significantly decreased the amplitude of LPP relative to that under controlled-processing unpleasant ones in an early window in the low depression group and that this regulatory effect was impaired in the high depression group. Furthermore, a mediation analyses indicated that the regulatory efficacy of controlled-processing different semantic representations was associated with SDS score via the mediation of rumination. These findings shed light on the mechanisms underlying the association between the function of cognitive control in emotion generation and depressive symptoms and indicated a pathway from the regulatory efficacy of cognitive control to depression via rumination.

Effects of Left Versus Right Dorsolateral Prefrontal Cortex Repetitive Transcranial Magnetic Stimulation on Affective Flexibility in Healthy Women: A Pilot Study

OBJECTIVE

To determine the antidepressant mechanism of action for repetitive transcranial magnetic stimulation (rTMS) to the left dorsolateral prefrontal cortex (DLPFC) in healthy women. Our primary hypothesis was that a single session of left DLPFC rTMS, compared with a session of right DLPFC rTMS, would result in better (reduced) negative nonaffective switch costs in healthy women.

BACKGROUND

The antidepressant mechanism of action for rTMS is not clear. It is possible that rTMS to the DLPFC improves emotion regulation, which could be a part of its antidepressant mechanism.

METHODS

Twenty-five healthy women were randomized to receive left high-frequency (HF) rTMS versus right HF rTMS in one session and then contralateral stimulation during a second session. Emotion regulation was assessed via switch costs for reappraisal of negatively valenced information on an affective flexibility task.

RESULTS

For negative nonaffective switch costs, the interaction effect in the two-way ANOVA was not significant (F1,19=3.053, P=0.097). Given that left HF rTMS is the approved treatment for depression, post hoc t tests were completed with particular interest in the left-side findings. These tests confirmed that negative nonaffective switch costs significantly improved immediately after left rTMS (t1,19=2.664, P=0.015) but not right rTMS.

CONCLUSIONS

These findings suggest that left DLPFC HF rTMS may lead to antidepressant effects by improving the regulation of emotion.

Early childhood depression, emotion regulation, episodic memory, and hippocampal development

Depression in adults is associated with deficits in a number of cognitive domains, however it remains less clear how early in development theses deficits can be detected in early onset depression. There are several different hypotheses about the links between cognitive function and depression. For example, it has been argued that executive function deficits contribute to emotion regulation difficulties, which in turn increase risk for depression. Further, it has been suggested that some cognitive deficits, such as episodic memory, may reflect hippocampal abnormalities linked to both depression and episodic memory. We examined these questions in adolescents participating in a longitudinal study of preschool onset depression. We measured cognitive function at adolescence using the National Institutes of Health toolbox (vocabulary, processing speed, executive function, working memory and episodic memory), and examined relationships of cognitive deficits to depression, emotion regulation, life stress and adversity, as well as hippocampal volume trajectories over three imaging assessments starting at school age. Depression related deficits in episodic memory were found. Youths with either current and past depression showed episodic memory deficits even after controlling for other psychopathology and family income. Depression severity, emotion dysregulation, and life stress/adversity all predicted episodic memory impairment, as did smaller intercepts and slopes of hippocampal growth over time. Modest relationships of depression to hippocampal volume and strong relationships between emotion regulation and both episodic memory and hippocampal volume were found. These data are consistent with prior work in adults linking depression, episodic memory, emotion regulation, life stress/adversity, and hippocampal volume in adults and suggest similar relations are evident as early as adolescence when memory systems are under development. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Longitudinal Relations Between Depressive Symptoms and Executive Functions From Adolescence to Early Adulthood: A Twin Study

Depression is associated with deficits in executive functions (EFs)-cognitive control abilities that regulate goal-directed thoughts and actions-but the etiology of these associations is unclear. We examined the relations between depressive symptoms and multiple EF latent variables in a population-based sample of 439 twin pairs assessed at mean ages 12, 17, and 23 years. Greater depressive symptoms negatively related to a Common EF factor capturing shared variance across response inhibition, working memory updating, and mental set shifting tasks, and also negatively related to an Updating-Specific factor, but not a Shifting-Specific factor. Cross-lagged panel models suggested that the Common EF correlations reflected within-wave associations rather than prospective effects, whereas the Updating-Specific correlations reflected associations of earlier depression levels with later Updating-Specific ability. Twin models were consistent with a model in which Common EF and Updating-Specific abilities relate to depression through correlated genetic risk, with no significant environmental correlations.

The removal of information from working memory

What happens to goal-relevant information in working memory after it is no longer needed? Here, we review evidence for a selective removal process that operates on outdated information to limit working memory load and hence facilitates the maintenance of goal-relevant information. Removal alters the representations of irrelevant content so as to reduce access to it, thereby improving access to the remaining relevant content and also facilitating the encoding of new information. Both behavioral and neural evidence support the existence of a removal process that is separate from forgetting due to decay or interference. We discuss the potential mechanisms involved in removal and characterize the time course and duration of the process. In doing so, we propose the existence of two forms of removal: one is temporary, and reversible, which modifies working memory content without impacting content-to-context bindings, and another is permanent, which unbinds the content from its context in working memory (without necessarily impacting long-term forgetting). Finally, we discuss limitations on removal and prescribe conditions for evaluating evidence for or against this process.

Effort-cost decision-making in psychosis and depression: could a similar behavioral deficit arise from disparate psychological and neural mechanisms?

Motivational impairment is a common feature of both depression and psychosis; however, the psychological and neural mechanisms that give rise to motivational impairment in these disorders are poorly understood. Recent research has suggested that aberrant effort-cost decision-making (ECDM) may be a potential contributor to motivational impairment in both psychosis and depression. ECDM refers to choices that individuals make regarding the amount of 'work' they are willing to expend to obtain a certain outcome or reward. Recent experimental work has suggested that those with psychosis and depression may be less willing to expend effort to obtain rewards compared with controls, and that this effort deficit is related to motivational impairment in both disorders. In the current review, we aim to summarize the current literature on ECDM in psychosis and depression, providing evidence for transdiagnostic impairment. Next, we discuss evidence for the hypothesis that a seemingly similar behavioral ECDM deficit might arise from disparate psychological and neural mechanisms. Specifically, we argue that effort deficits in psychosis might be largely driven by deficits in cognitive control and the neural correlates of cognitive control processes, while effort deficits in depression might be largely driven by reduced reward responsivity and the associated neural correlates of reward responsivity. Finally, we will provide some discussion regarding future directions, as well as interpretative challenges to consider when examining ECDM transdiagnostically.

Affective enhancement of working memory is maintained in depression

We currently know little about how performance on assessments of working memory capacity (WMC) that are designed to mirror the concurrent task demands of daily life are impacted by the presence of affective information, nor how those effects may be modulated by depression-a syndrome where sufferers report global difficulties with executive processing. Across 3 experiments, we investigated WMC for sets of neutral words in the context of processing either neutral or affective (depressogenic) sentences, which had to be judged on semantic accuracy (Experiments 1 and 2) or self-reference (Experiment 3). Overall, WMC was significantly better in the context of depressogenic compared with neutral sentences. However, there was no support for this effect being modulated by symptoms of depression (Experiment 1) or the presence of recurrent major depressive disorder (MDD; Experiments 2 and 3). Implications of these findings for cognitive theories of the role of WM in depression are discussed in the context of a growing body of research showing no support for a differential impact of depressogenic compared with neutral information on WM accuracy. (PsycINFO Database Record

Effects of Transcranial Magnetic Stimulation on the Cognitive Control of Emotion: Potential Antidepressant Mechanisms

Depression negatively impacts quality of life and is associated with high mortality rates. Recent research has demonstrated that improvement in depression symptoms with transcranial magnetic stimulation (TMS) to the dorsolateral prefrontal cortex (DLPFC) may involve changes in the cognitive control network, a regulatory system modulating the function of cognitive and emotional systems, composed of the DLPFC, dorsal anterior cingulate, and posterior parietal cortices. Transcranial magnetic stimulation to the DLPFC node of the cognitive control network may have antidepressant efficacy via direct effects on cognitive control processes involved in emotion regulation. This review provides a review of the impact of TMS on cognitive control processes, especially those related to emotion regulation, and posits that these effects are critical to the mechanism of action of TMS for depression. Treatment implications and future directions for study are discussed.

Alterations in visual cortical activation and connectivity with prefrontal cortex during working memory updating in major depressive disorder

The present study examined the impacts of major depressive disorder (MDD) on visual and prefrontal cortical activity as well as their connectivity during visual working memory updating and related them to the core clinical features of the disorder. Impairment in working memory updating is typically associated with the retention of irrelevant negative information which can lead to persistent depressive mood and abnormal affect. However, performance deficits have been observed in MDD on tasks involving little or no demand on emotion processing, suggesting dysfunctions may also occur at the more basic level of information processing. Yet, it is unclear how various regions in the visual working memory circuit contribute to behavioral changes in MDD. We acquired functional magnetic resonance imaging data from 18 unmedicated participants with MDD and 21 age-matched healthy controls (CTL) while they performed a visual delayed recognition task with neutral faces and scenes as task stimuli. Selective working memory updating was manipulated by inserting a cue in the delay period to indicate which one or both of the two memorized stimuli (a face and a scene) would remain relevant for the recognition test. Our results revealed several key findings. Relative to the CTL group, the MDD group showed weaker postcue activations in visual association areas during selective maintenance of face and scene working memory. Across the MDD subjects, greater rumination and depressive symptoms were associated with more persistent activation and connectivity related to no-longer-relevant task information. Classification of postcue spatial activation patterns of the scene-related areas was also less consistent in the MDD subjects compared to the healthy controls. Such abnormalities appeared to result from a lack of updating effects in postcue functional connectivity between prefrontal and scene-related areas in the MDD group. In sum, disrupted working memory updating in MDD was revealed by alterations in activity patterns of the visual association areas, their connectivity with the prefrontal cortex, and their relationship with core clinical characteristics. These results highlight the role of information updating deficits in the cognitive control and symptomatology of depression.

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Unmedicated individuals with major depressive disorder showed several forms of deficits during visual working memory updating.

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Impaired visual working memory updating performance.

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Diminished category-specific response patterns in visual association areas, particularly those involved in scene processing.

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Loss of frontal functional connectivity with the scene-selective visual region during updating of scene information.

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Rumination is associated with heightened activity and functional connectivity for obsolete information in working memory.

Internal switching and backward inhibition in depression and rumination

Prior research has suggested that impairments of switching abilities are associated with depression as well as rumination. Backward inhibition (BI) refers to the ability to inhibit the processing of previously relevant information and is demonstrated to be one of the key mechanisms underlying switching abilities. However, the association between BI in internal switching and depression/rumination remains uninvestigated. To examine this association, a modified Internal Shifting Task (IST) was administered to a sample of dysphoric and healthy control undergraduates. Results showed that depressive symptoms were not associated with difficulties in switching among subjects held in working memory, while trait ruminators performed poorly in switching internally. Surprisingly, no association between BI in internal switching and rumination/depressive symptoms was found. These findings indicate that rumination is characterized by poor performance in internal switching, but this deficit is not associated with BI.

Die Bedeutung kognitiver Beeinträchtigungen bei depressiven Patienten

Zusammenfassung. Beeinträchtigungen der Exekutivfunktionen, der Aufmerksamkeit und des Gedächtnisses sind einige der häufigsten und hartnäckigsten Symptome depressiver Störungen. Bisher konnte allerdings kein eindeutiges Profil dieser Defizite identifiziert werden, wahrscheinlich auch deshalb, weil die Defizite von verschiedenen klinischen und demografischen Faktoren, wie dem Depressionssubtypus, Grübeln, Komorbiditäten und Alter beeinflusst werden. Die kognitiven Beeinträchtigungen verbessern sich mit der Remission der Störung, häufig findet jedoch keine vollständige Rückbildung statt. Sie sind klinisch sehr relevant und gehen einher mit Suizidalität, reduzierten Therapieeffekten und negativen Auswirkungen auf Alltagsaktivitäten. Aus diesen Gründen ergibt sich für betroffene Patienten die Notwendigkeit einer neuropsychologischen Behandlung. Erste Ergebnisse lassen hoffen, dass die kognitiven Beeinträchtigungen mithilfe neuropsychologischer Therapie, Achtsamkeitstraining, psychopharmakologischer Therapie und weiteren neurobiologischen Behandlungen, wie z. B. der repetitiven transkraniellen Magnetstimulation, erfolgreich behandelt werden können.

Updating emotional content in recovered depressed individuals: Evaluating deficits in emotion processing following a depressive episode

BACKGROUND AND OBJECTIVES

Previous research has demonstrated that depressed individuals have difficulty both disengaging from negative information and maintaining positive information in working memory (WM). The present study was conducted to examine whether the tendency for depressed individuals to maintain negative content in WM and to experience difficulties maintaining positive content in WM is due to negative mood (in)congruency effects during a depressive episode, or whether these tendencies are evident outside of a depressive episode.

METHODS

Individuals who had recovered from a depressive episode and never disordered controls performed emotion 0-back and 2-back tasks designed to assess biases in updating emotional content in working memory.

RESULTS

Similar to currently depressed individuals in previous studies, recovered depressed participants disengaged from happy stimuli more quickly and from sad stimuli more slowly than did their never-depressed counterparts.

LIMITATIONS

Despite the extension of a depression-specific finding to recovered depressed individuals, the present study does not test whether the identified emotion updating biases predict long-term relapse or recovery.

CONCLUSION

The obtained results suggest that a decreased ability to disengage from negative content and to maintain positive content in WM represents a trait-like cognitive style that impairs adaptive emotion regulation and may contribute to the recurrent nature of depression.

Surface vulnerability of cerebral cortex to major depressive disorder

Major depressive disorder (MDD) is accompanied by atypical brain structure. This study first presents the alterations in the cortical surface of patients with MDD using multidimensional structural patterns that reflect different neurodevelopment. Sixteen first-episode, untreated patients with MDD and 16 matched healthy controls underwent a magnetic resonance imaging (MRI) scan. The cortical maps of thickness, surface area, and gyrification were examined using the surface-based morphometry (SBM) approach. Increase of cortical thickness was observed in the right posterior cingulate region and the parietal cortex involving the bilateral inferior, left superior parietal and right paracentral regions, while decreased thickness was noted in the parietal cortex including bilateral pars opercularis and left precentral region, as well as the left rostral-middle frontal regions in patients with MDD. Likewise, increased or decreased surface area was found in five sub-regions of the cingulate gyrus, parietal and frontal cortices (e.g., bilateral inferior parietal and superior frontal regions). In addition, MDD patients exhibited a significant hypergyrification in the right precentral and supramarginal region. This integrated structural assessment of cortical surface suggests that MDD patients have cortical alterations of the frontal, parietal and cingulate regions, indicating a vulnerability to MDD during earlier neurodevelopmental process.