Emotional working memory training reduces rumination and alters the EEG microstate in anxious individuals

A Systematic Review and Narrative Synthesis of Cognitive Training in the Treatment of Mental Illness and Substance Use Disorder

Introduction: The one unifying and distinguishing feature of all neuropsychiatric illnesses is the co-occurrence of cognitive dysfunction. Cognitive training (CT) was developed to enhance neural connectivity and cognition and improve day-to-day functioning. However, the benefits of CT are still debated. This current systematic review aimed to examine the efficacy of CT and to identify diagnostic and CT characteristics associated with superior outcomes across a range of psychiatric disorders. Method: Studies investigating CT in psychiatric illnesses were extracted from Embase, PubMed, CINAHL, PsycINFO, and PsycARTICLES up to 17 August 2023. Inclusion criteria were randomised control trials (RCT) and English language. The primary search strategy included terms relating to cognitive training, cognitive remediation, cognitive enhancement, or cognitive rehabilitation and randomised control trials, clinical trials, or experiments. Risk of bias was assessed using RevMan Web version 8.1.1. Narrative synthesis was used to analyse findings. Due to the heterogeneity of participant demographics, diagnoses, and interventions, meta-analyses were considered inappropriate. Results: Fifteen studies, including a total of 1075 participants, were identified. Approximately 67% of studies reported significant improvements in at least one trained domain of cognitive function after CT, and 47% observed improvements in psychiatric symptoms or function. Cognitive transfer effects were not observed. Sample sizes for studies were generally small, and most CT durations were 6 weeks or less. Conclusions: Findings suggest that CT can improve cognitive function in trained domains, though little evidence of cognitive transfer effects was observed. Due to the lack of standardisation in CT format and delivery, and inadequate measures of psychiatric symptoms or daily function, there is insufficient evidence to conclude whether or not this technique may benefit cognitive impairment in psychiatric disorders, or lead to subsequent improvement in disease symptomatology. Further studies of longer duration and using consistent methodologies must be conducted to identify the benefits of CT in psychiatric disorders.

Worry and rumination as a transdiagnostic target in young people: a co-produced systematic review and meta-analysis

PROTOCOL REGISTRATION

PROSPERO (CRD42023408899).

Changes in electroencephalographic microstates between evening and morning are associated with overnight sleep slow waves in healthy individuals

STUDY OBJECTIVES

Microstates are semi-stable voltage topographies that account for most of electroencephalogram (EEG) variance. However, the impact of time of the day and sleep on microstates has not been examined. To address this gap, we assessed whether microstates differed between the evening and morning and whether sleep slow waves correlated with microstate changes in healthy participants.

METHODS

Forty-five healthy participants were recruited. Each participant underwent 6 minutes of resting state EEG recordings in the evening and morning, interleaved by sleep EEGs. Evening-to-morning changes in microstate duration, coverage, and occurrence were assessed. Furthermore, correlation between microstate changes and sleep slow-wave activity (SWA) and slow-wave density (SWD) were performed.

RESULTS

Two-way ANOVAs with microstate class (A, B, C, and D) and time (evening and morning) revealed significant microstate class × time interaction for duration (F(44) = 5.571, p = 0.002), coverage (F(44) = 6.833, p = 0.001), and occurrence (F(44) = 5.715, p = 0.002). Post hoc comparisons showed significant effects for microstate C duration (padj = 0.048, Cohen's d = -0.389), coverage (padj = 0.002, Cohen's d = -0.580), and occurrence (padj = 0.002, Cohen's d = -0.606). Topographic analyses revealed inverse correlations between SWD, but not SWA, and evening-to-morning changes in microstate C duration (r = -0.51, padj = 0.002), coverage (r = -0.45, padj = 0.006), and occurrence (r = -0.38, padj = 0.033).

CONCLUSIONS

Microstate characteristics showed significant evening-to-morning changes associated with, and possibly regulated by, sleep slow waves. These findings suggest that future microstate studies should control for time of day and sleep effects.

Valence-specific EEG microstate modulations during self-generated affective states

Introduction

This study aims to explore the temporal dynamics of brain networks involved in self-generated affective states, specifically focusing on modulating these states in both positive and negative valences. The overarching goal is to contribute to a deeper understanding of the neurodynamic patterns associated with affective regulation, potentially informing the development of biomarkers for therapeutic interventions in mood and anxiety disorders.

Methods

Utilizing EEG microstate analysis during self-generated affective states, we investigated the temporal dynamics of five distinct microstates across different conditions, including baseline resting state and self-generated states of positive valence (e.g., awe, contentment) and negative valence (e.g., anger, fear).

Results

The study revealed noteworthy modulations in microstate dynamics during affective states. Additionally, valence-specific mechanisms of spontaneous affective regulation were identified. Negative valence affective states were characterized by the heightened presence of attention-associated microstates and reduced occurrence of salience-related microstates during negative valence states. In contrast, positive valence affective states manifested a prevalence of microstates related to visual/autobiographical memory and a reduced presence of auditory/language-associated microstates compared to both baseline and negative valence states.

Discussion

This study contributes to the field by employing EEG microstate analysis to discern the temporal dynamics of brain networks involved in self-generated affective states. Insights from this research carry significant implications for understanding neurodynamic patterns in affective regulation. The identification of valence-specific modulations and mechanisms has potential applications in developing biomarkers for mood and anxiety disorders, offering novel avenues for therapeutic interventions.

Change in Resting-State Functional Connectivity Following Working Memory Training in Individuals With Repetitive Negative Thinking

BACKGROUND

Repetitive negative thinking (RNT) symptoms, which are characterized by pervasive, uncontrollable negative thoughts, are common in individuals with mood, anxiety, and traumatic stress disorders. Inability to regulate the contents of working memory is a hypothesized etiological factor in RNT, which suggests that training to improve working memory may be beneficial. This study examined the effects of working memory training on resting-state functional connectivity (rsFC) in individuals with elevated RNT and whether such changes would be associated with clinical improvement.

METHODS

We conducted a secondary analysis of pre-post resting-state data collected as part of a randomized controlled trial (NCT04912089) of working memory training interventions (n = 42) compared with a waitlist control group (n = 23). We hypothesized that individuals who completed training would show increased rsFC between the 2 key intrinsic connectivity networks-the default mode network (posterior cingulate cortex) and the frontoparietal network (dorsolateral prefrontal cortex). We explored whether the magnitude of rsFC change was associated with change in RNT symptom severity.

RESULTS

rsFC increased between the posterior cingulate cortex and regions including the frontal and parietal cortex in the training group compared with the waitlist group. Increased connectivity between the posterior cingulate cortex and superior frontal cortex was associated with RNT symptom reduction.

CONCLUSIONS

These data provide evidence that working memory training can modulate neural circuitry at rest in individuals with RNT. Results are consistent with accounts of working memory training effects on large-scale neurocircuitry changes and suggest that these changes may contribute to clinical promise of this type of intervention on transdiagnostic RNT symptoms.

Open access EEG dataset of repeated measurements from a single subject for microstate analysis

Electroencephalography (EEG) microstate analysis is a neuroimaging analytical method that has received considerable attention in recent years and is widely used for analysing EEG signals. EEG is easily influenced by internal and external factors, which can affect the repeatability and stability of EEG microstate analysis. However, there have been few reports and publicly available datasets on the repeatability of EEG microstate analysis. In the current study, a 39-year-old healthy male underwent a total of 60 simultaneous electroencephalography and electrocardiogram measurements over a period of three months. After the EEG recording was completed, magnetic resonance imaging (MRI) was also conducted. To date, this EEG dataset has the highest number of repeated measurements for one individual. The dataset can be used to assess the stability and repeatability of EEG microstates and other analytical methods, to decode resting EEG states among subjects with open eyes, and to explore the stability and repeatability of cortical spatiotemporal dynamics through source analysis with individual MRI.

Childhood Trauma and Depressive Level Among Chinese College Students in Guangzhou: The Roles of Rumination and Perceived Stress

OBJECTIVE

Although previous studies have validated the effect of childhood trauma on depressive level, few studies have utilized the diathesis-stress theory to investigate the specific roles of perceived stress and rumination in the pathway between childhood trauma and depression in Chinese college students. This study aims to demonstrate the mediation effect of perceived stress and the moderation effect of rumination in the pathway between childhood trauma and depressive level in Chinese college students.

METHODS

A total of 995 Chinese college students in Guangzhou were included in this study by recruitment advertisement from October to December 2021. And they were asked to finish four self-report questionnaires, including Childhood Trauma Questionnaire-Short Form, Perceived Stress Scale, the 22-item Ruminative Response Scale, and Beck Depression Scale-II. Then the data were analyzed with Mplus 8.3.

RESULTS

Results revealed significant correlations among childhood trauma, perceived stress, rumination and depressive level. Further analyses revealed that perceived stress played a mediation role between childhood trauma and depressive level (estimate=0.09, standard error [SE]=0.02, t=5.93, 95% confidence interval [CI]=0.06-0.12), and rumination played a moderation role between childhood trauma and perceived stress (estimate=-0.17, SE=0.06, t=-2.86, 95% CI=-0.28- -0.05]) as well as between childhood trauma and depressive level (estimate=0.10, SE=0.04, t=2.74, 95% CI=0.03-0.16).

CONCLUSION

These results revealed the mediation effect of perceived stress and the moderation effect of rumination in the pathway between childhood trauma and depressive level in Chinese college students, which helped us to understand how the childhood trauma influenced the depressive level and gave us multi-dimensional indications for reducing the effect of childhood trauma on depressive level.

The Functional Aspects of Resting EEG Microstates: A Systematic Review

A growing body of clinical and cognitive neuroscience studies have adapted a broadband EEG microstate approach to evaluate the electrical activity of large-scale cortical networks. However, the functional aspects of these microstates have not yet been systematically reviewed. Here, we present an overview of the existing literature and systematize the results to provide hints on the functional role of electrical brain microstates. Studies that evaluated and manipulated the temporal properties of resting-state microstates and utilized questionnaires, task-initiated thoughts, specific tasks before or between EEG session(s), pharmacological interventions, neuromodulation approaches, or localized sources of the extracted microstates were selected. Fifty studies that met the inclusion criteria were included. A new microstate labeling system has been proposed for a comprehensible comparison between the studies, where four classical microstates are referred to as A-D, and the others are labeled by the frequency of their appearance. Microstate A was associated with both auditory and visual processing and links to subjects' arousal/arousability. Microstate B showed associations with visual processing related to self, self-visualization, and autobiographical memory. Microstate C was related to processing personally significant information, self-reflection, and self-referential internal mentation rather than autonomic information processing. In contrast, microstate E was related to processing interoceptive and emotional information and to the salience network. Microstate D was associated with executive functioning. Microstate F is suggested to be a part of the Default Mode Network and plays a role in personally significant information processing, mental simulations, and theory of mind. Microstate G is potentially linked to the somatosensory network.

Normative Temporal Dynamics of Resting EEG Microstates

The large-scale electrophysiological events known as electroencephalographic microstates provide an important window into the intrinsic activity of whole-brain neuronal networks. The spontaneous activity of coordinated brain networks, including the ongoing temporal dynamics expressed by microstates, are thought to reflect individuals' neurocognitive functioning, and predict development, disease progression, and psychological differences among varied populations. A comprehensive understanding of human brain function therefore requires characterizing typical and atypical patterns in the temporal dynamics of microstates. But population-level estimates of normative microstate temporal dynamics are still unknown. To address this gap, I conducted a systematic search of the literature and accompanying meta-analysis of the average dynamics of microstates obtained from studies investigating spontaneous brain activity in individuals during periods of eyes-closed and eyes-open rest. Meta-analyses provided estimates of the average temporal dynamics of microstates across 93 studies totaling 6583 unique individual participants drawn from diverse populations. Results quantified the expected range of plausible estimates of average microstate dynamics across study samples, as well as characterized heterogeneity resulting from sampling variability and systematic differences in development, clinical diagnoses, or other study methodological factors. Specifically, microstate dynamics significantly differed for samples with specific developmental differences or clinical diagnoses, relative to healthy, typically developing samples. This research supports the notion that microstates and their dynamics reflect functionally relevant properties of large-scale brain networks, encoding typical and atypical neurocognitive functioning.

Disrupted properties of functional brain networks in major depressive disorder during emotional face recognition: an EEG study via graph theory analysis

Previous neuroimaging studies have revealed abnormal brain networks in patients with major depressive disorder (MDD) in emotional processing. While any cognitive task consists of a series of stages, little is yet known about the topology of functional brain networks in MDD for these stages during emotional face recognition. To address this problem, electroencephalography (EEG)-based functional brain networks of MDD patients at different stages of facial information processing were investigated in this study. First, EEG signals were collected from 16 patients with MDD and 18 age-, gender-, and education-matched normal subjects when performing an emotional face recognition task. Second, the global field power (GFP) method was employed to divide group-averaged event-related potentials into different stages. Third, using the phase transfer entropy (PTE) approach, the brain networks of MDD patients and normal individuals were constructed for each stage in negative and positive face processing, respectively. Finally, we compared the topological properties of brain networks of each stage between the two groups using graph theory approaches. The results showed that the analyzed three stages of emotional face processing corresponded to specific neurophysiological phases, namely, visual perception, face recognition, and emotional decision-making. It was also demonstrated that depressed patients showed abnormally decreased characteristic path length at the visual perception stage of negative face recognition and normalized characteristic path length in the stage of emotional decision-making during positive face processing compared to healthy subjects. Furthermore, while both the MDD and normal groups' brain networks were found to exhibit small-world network characteristics, the brain network of patients with depression tended to be randomized. Moreover, for patients with MDD, the centro-parietal region may lose its status as a hub in the process of facial expression identification. Together, our findings suggested that altered emotional function in MDD patients might be associated with disruptions in the topological organization of functional brain networks during emotional face recognition, which further deepened our understanding of the emotion processing dysfunction underlying MDD.

Changes in affective control covary with changes in mental health difficulties following affective control training (AffeCT) in adolescents

BACKGROUND

Everyday affective fluctuations are more extreme and more frequent in adolescence compared to any other time in development. Successful regulation of these affective experiences is important for good mental health and has been proposed to depend on affective control. The present study examined whether improving affective control through a computerised affective control training app (AffeCT) would benefit adolescent mental health.

METHODS

One-hundred and ninety-nine participants (11-19 years) were assigned to complete 2 weeks of AffeCT or placebo training on an app. Affective control (i.e. affective inhibition, affective updating and affective shifting), mental health and emotion regulation were assessed at pre- and post-training. Mental health and emotion regulation were assessed again one month and one year later.

RESULTS

Compared with the placebo group, the AffeCT group showed significantly greater improvements in affective control on the trained measure. AffeCT did not, relative to placebo, lead to better performance on untrained measures of affective control. Pre- to post-training change in affective control covaried with pre- to post-training change in mental health problems in the AffeCT but not the placebo group. These mental health benefits of AffeCT were only observed immediately following training and did not extend to 1 month or year post-training.

CONCLUSION

In conclusion, the study provides preliminary evidence that AffeCT may confer short-term preventative benefits for adolescent mental health.

Adjunctive cognitive training with exposure enhances fear and neural outcomes in social anxiety

Exposure-based cognitive behavioral therapy (CBT) is the gold standard for treating social anxiety disorder (SAD), yet response is not universal. CBT is thought to operate via extinction-related learning during exposure, which in turn relies on cognitive processes such as working memory. The present proof-of-concept study investigates the potential for training working memory to improve anxiety related outcomes following exposure. Thirty-three adults with elevated social anxiety were randomized to complete a working memory training or sham training condition. Post-training, participants completed a working memory assessment, speech exposure session, and two fMRI tasks. Participants who received working memory training demonstrated lower distress ratings by the end of the speech exposures and better performance on the fMRI working memory task than those in sham. Working memory training completers had greater neural activation in frontoparietal regions during an in-scanner working memory task and exhibited less neural activation in the fusiform gyrus in response to an emotional face processing task than those in sham. Adding working memory training to exposure procedures could strengthen functioning of frontoparietal regions and alter emotional processing - key mechanisms implicated in extinction learning. Findings provide preliminary evidence that training working memory in conjunction with exposure may enhance exposure success.

Rumination burdens the updating of working memory

Working memory is a vital, but capacity-limited, cognitive instrument that requires frequent updating as our goals and environment change. Individuals diagnosed with depression have a reduced capacity compared with the general population, as they have a propensity to fixate on negative information, even when it is not relevant for the task at hand. Here we investigated how characteristics of psychiatric illnesses, such as rumination, affect a person's ability to efficiently update emotional information in mind. We used both neutral and negative pictures of scenes in a working memory updating task that required participants to occasionally replace items held in mind during a brief delay period. Participants were presented with a probe item at the end of each trial and asked to report whether that item was in their current memory set. Responses were slowest and least accurate for images that had been replaced (i.e., "lures"), indicating there was some difficulty in successfully updating working memory in this paradigm. Participants who have both a high propensity to ruminate and a low working memory capacity were significantly more likely to false alarm to these lures. While emotional valence did not impact accuracy for these participants, their false alarms were faster for negative stimuli compared with neutral stimuli, indicating that task-irrelevant emotional information was more difficult to remove from working memory. These results demonstrate how rumination impairs goal-directed behavior by obscuring the boundary between relevant and irrelevant information in working memory.

Event-related microstate dynamics represents working memory performance

In recent years, EEG microstate analysis has attracted much attention as a tool for characterizing the spatial and temporal dynamics of large-scale electrophysiological activities in the human brain. Canonical 4 states (classes A, B, C, and D) have been widely reported, and they have been pointed out for their relationships with cognitive functions and several psychiatric disorders such as schizophrenia, in particular, through their static parameters such as average duration, occurrence, coverage, and transition probability. However, the relationships between event-related microstate changes and their related cognitive functions, as is often analyzed in event-related potentials under time-locked frameworks, is still not well understood. Furthermore, not enough attention has been paid to the relationship between microstate dynamics and static characteristics. To clarify the relationships between the static microstate parameters and dynamic microstate changes, and between the dynamics and working memory (WM) function, we first examined the temporal profiles of the microstates during the N-back task. We found significant event-related microstate dynamics that differed predominantly with WM loads, which were not clearly observed in the static parameters. Furthermore, in the 2-back condition, patterns of state transitions from class A to C in the high- and low-performance groups showed prominent differences at 50-300 ms after stimulus onset. We also confirmed that the transition patterns of the specific time periods were able to predict the performance level (low or high) in the 2-back condition at a significant level, where a specific transition between microstates, namely from class A to C with specific polarity, contributed to the prediction robustly. Taken together, our findings indicate that event-related microstate dynamics at 50-300 ms after onset may be essential for WM function. This suggests that event-related microstate dynamics can reflect more highly-refined brain functions.

Time Perspective, Working Memory, and Depression in Non-Clinical Samples: Is There a Link?

Non-clinical depression is a major issue on college campuses, with some surveys estimating that 30% of college students have experienced a major depressive episode. One theoretical framework of depression is Zimbardo and Boyd (1999) time perspective model, which posits that our perspectives on time impact different aspects of life including our emotions, judgments, and decision making. The current study seeks to determine the role of this time perspectives model and a range of cognitive constructs including hope, rumination, and working memory on their influence in depression. Currently enrolled college students and participants not currently enrolled in college completed the Center for Epidemiologic Studies Depression Scale, the Zimbardo Time Perspective Inventory, the Adult Hope Scale, the Rumination Reflection Questionnaire, and the Automated Working Memory Assessment. Linear regression analysis revealed that, for the college students, Rumination and Past Negative scores predicted depressive symptoms. For the non-college students, Rumination, Present Fatalism, Hope Agency and Verbal Working Memory scores predicted depressive symptoms. The current results reiterate the importance of rumination in depression symptomology and that current cognitive depression models and treatments may benefit from including time perspective measures. Further implications of the results are discussed.

Development of a gamified cognitive training app “Social Brain Train” to enhance adolescent mental health: a participatory design study protocol

Background: Adolescence is a sensitive period for the onset of mental health disorders. Effective, easy-to-disseminate, scalable prevention and early interventions are urgently needed. Affective control has been proposed as a potential target mechanism. Training affective control has been shown to reduce mental health symptoms and improve emotion regulation. However, uptake and adherence to such training by adolescents has been low. Thus, the current study aims to receive end user (i.e., adolescents) feedback on a prototype of a novel app-based gamified affective control training program, the Social Brain Train. Methods: The proposed study aims to recruit participants aged 13-16 years old (N = 20) to provide user feedback on the Social Brain Train app. The first group of participants (n = 5) will complete an online questionnaire assessing demographics, symptoms of depression and anxiety, social rejection sensitivity and attitudes toward the malleability of cognition and mental health. They will complete two tasks assessing cognitive capacity and interpretation bias. Participants will be then be invited to an online group workshop, where they will be introduced to the app. They will train on the app for three days, and following app usage, participants will complete the aforementioned measures again, as well as provide ratings on app content, and complete a semi-structured interview to obtain in-depth user feedback, which will be used to inform modifications to the app. Following these modifications, a second group of participants (n = 15) will follow the same procedure, except they will train on the app for 14 days. Feedback from both groups of participants will be used to inform the final design. Conclusions: By including young people in the design of the Social Brain Train app, the proposed study will help us to develop a novel mental health intervention that young people find engaging, acceptable, and easy-to-use

The effectiveness of affective compared to neutral working memory training in university students with test anxiety

BACKGROUND

Test anxiety (TA), defined as the emotional, physiological, and behavioural responses surrounding situations involving formal evaluation of performance, is a relatively common occurrence, and, when present, can be a disruptive factor in students' academic careers. Research indicates that working memory, in particular, affective working memory, is impaired in individuals with TA. The current study therefore explored whether training the application of working memory in affective contexts could reduce TA and associated cognitive and affective impairments.

METHOD

60 Iranian university students (50% female; 19-22 years) with TA symptoms were randomized to receive 20 sessions of affective working memory training (aWMT), neutral working memory training (nWMT) or to a no-training control group. Prior and immediately after training, all participants completed measures of TA, working memory, cognitive control, and emotion regulation.

RESULTS

Compared to the control group, both the aWMT and the nWMT groups demonstrated improved cognitive and affective functioning from pre-to post-training. However, the reduction in TA symptoms and improvement in emotion regulation was greater in the aWMT group compared to the nWMT group.

CONCLUSION

aWMT may be an effective means of not only reducing TA, but also enhancing cognitive and affective functioning. These preliminary findings are promising given the potential for free and easy dissemination of aWMT in schools and online settings, including low- and middle-income countries.