Working memory capacity and suppression of intrusive thoughts

Neural basis underlying the association between thought control ability and happiness: The moderating role of the amygdala

Thought control ability (TCA) plays an important role in individuals' health and happiness. Previous studies demonstrated that TCA was closely conceptually associated with happiness. However, empirical research supporting this relationship was limited. In addition, the neural basis underlying TCA and how this neural basis influences the relationship between TCA and happiness remain unexplored. In the present study, the voxel-based morphometry (VBM) method was adopted to investigate the neuroanatomical basis of TCA in 314 healthy subjects. The behavioral results revealed a significant positive association between TCA and happiness. On the neural level, there was a significant negative correlation between TCA and the gray matter density (GMD) of the bilateral amygdala. Split-half validation analysis revealed similar results, further confirming the stability of the VBM analysis findings. Furthermore, gray matter covariance network and graph theoretical analyses showed positive association between TCA and both the node degree and node strength of the amygdala. Moderation analysis revealed that the GMD of the amygdala moderated the relationship between TCA and happiness. Specifically, the positive association between TCA and self-perceived happiness was stronger in subjects with a lower GMD of the amygdala. The present study indicated the neural basis underlying the association between TCA and happiness and offered a method of improving individual well-being.

Low working memory reduces the use of mental contrasting

Mentally contrasting a desired future with reality is a self-regulation strategy that helps people effectively pursue important personal wishes. People with higher self-regulation skills are more likely to spontaneously use mental contrasting. Because one central cognitive function underlying self-regulation is working memory capacity, we investigated whether people with low rather than high working memory capacity are less likely to spontaneously use mental contrasting. Study 1 provided correlational evidence that participants with lower working memory capacity, as measured by the Operation-Span Task, were less likely to use mental contrasting when elaborating an important interpersonal wish. Study 2 provided experimental evidence that manipulating low working memory capacity by inducing cognitive load (vs. no load) led fewer participants to use mental contrasting. The findings have theoretical implications by illuminating the processes that impede mental contrasting, and they have applied implications for understanding how to foster the use of mental contrasting in everyday life.

Structural Fingerprinting of the Frontal Aslant Tract: Predicting Cognitive Control Capacity and Obsessive-Compulsive Symptoms

White matter of the human brain is influenced by common genetic variations and shaped by neural activity-dependent experiences. Variations in microstructure of cerebral white matter across individuals and even across fiber tracts might underlie differences in cognitive capacity and vulnerabilities to mental disorders. The frontoparietal and cingulo-opercular networks of the brain constitute the central system supporting cognitive functions, and functional connectivity of these networks has been used to distinguish individuals known as "functional fingerprinting." The frontal aslant tract (FAT) that passes through the two networks has been implicated in executive functions. However, whether FAT can be used as a "structural fingerprint" to distinguish individuals and predict an individual's cognitive function and dysfunction is unknown. Here we investigated the fingerprinting property of FAT microstructural profiles using three independent diffusion MRI datasets with repeated scans on human participants including both females and males. We found that diffusion and geometric profiles of FAT can be used to distinguish individuals with a high accuracy. Next, we demonstrated that fractional anisotropy in different FAT segments predicted distinct cognitive functions, including working memory, inhibitory control, and relational reasoning. Finally, we assessed the contribution of altered FAT microstructural profiles to cognitive dysfunction in unmedicated patients with obsessive-compulsive disorders. We found that the altered microstructure in FAT was associated with the severity of obsessive-compulsive symptoms. Collectively, our findings suggest that the microstructural profiles of FAT can identify individuals with a high accuracy and may serve as an imaging marker for predicting an individual's cognitive capacity and disease severity.SIGNIFICANCE STATEMENT The frontoparietal network and cingulo-opercular network of the brain constitute a dual-network architecture for human cognitive functions, and functional connectivity of these two networks can be used as a "functional fingerprint" to distinguish individuals. However, the structural underpinnings of these networks subserving individual heterogeneities in their functional connectivity and cognitive ability remain unknown. We show here that the frontal aslant tract (FAT) that passes through the two networks distinguishes individuals with a high accuracy. Further, we demonstrate that the diffusion profiles of FAT predict distinct cognitive functions in healthy subjects and are associated with the clinical symptoms in patients with obsessive-compulsive disorders. Our findings suggest that the FAT may serve as a unique structural fingerprint underlying individual cognitive capability.

A mindful approach to controlling intrusive thoughts

Intrusive thoughts of negative experiences can pose a threat to our well-being. To some extent, unwanted memories can be intentionally controlled via an executive control mechanism that downregulates the occurrence of intrusions. Mindfulness training can improve executive control. It is not known whether mindfulness training can be used as an intervention to improve intentional memory control and reduce intrusions. To this end, 148 healthy participants completed a 10-day app-based mindfulness training or an active control task. At baseline, inhibitory control and working memory were assessed as measures of executive functioning. Post-mindfulness training, intrusions were assessed via the Think/No-Think task. It was expected that mindfulness training would reduce intrusions. Furthermore, we hypothesised that this would be moderated by baseline executive functioning. Results revealed that, contrary to our hypothesis, both groups increased equally in dispositional mindfulness between baseline and post-test. As such, our exploratory analysis revealed that higher dispositional mindfulness across both groups resulted in fewer intrusions and enhanced the ability to downregulate intrusions over time. Furthermore, this effect was moderated by inhibitory control at baseline. These results provide insight into factors that can improve the ability to control unwanted memories, which could have considerable implications for treatments in psychopathologies characterized by the frequent occurrence of intrusive thoughts. PROTOCOL REGISTRATION: The stage 1 protocol for this Registered Report was accepted in principle on 11th March, 2022. The protocol, as accepted by the journal, can be found at: https://doi.org/10.17605/OSF.IO/U8SJN .

Deep brain stimulation of the subthalamic nucleus to improve symptoms and cognitive functions in patients with refractory obsessive-compulsive disorder: a longitudinal study

There are conflicting results regarding the effect of deep brain stimulation (DBS) of different regions on the cognitive functions of patients with severe refractory obsessive-compulsive disorder (OCD). Moreover, it is not yet clear whether the rate of improvement in obsession-compulsion symptoms and cognitive functions following DBS is interrelated. We investigated the effect of the subthalamic nucleus (STN)-DBS on both the severity of symptoms and cognitive functions of patients and also investigated the possible interrelationship between the two. Twelve patients (10 males and two females; 56.17 ± 4.52 years old) were assessed before and 1 month and 3 months after the DBS surgery using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the N-Back, the selective and divided attention (SDA), the Tower of London (TOL), and the Wisconsin Card Sorting (WCS) tests. We found that the severity of symptoms and cognitive functions improved significantly after DBS and this effect lasted at least up to 3 months. Furthermore, it was revealed that the severity of symptoms and cognitive profiles of patients were significantly correlated. Compulsion severity had the highest correlation with perseveration errors, while obsession severity was most correlated with the number of n-back errors. Based on our findings, it seems that the STN acts at least to some extent as a common functional/anatomical ground for the severity of symptoms and cognitive functions of patients with severe refractory OCD, and it can probably be considered as the region of interest for DBS in this group of patients.

A Systematic Review of Clinical Psychophysiology of Obsessive-Compulsive Disorders: Does the Obsession with Diet Also Alter the Autonomic Imbalance of Orthorexic Patients?

(1) Background: A new mental illness is attracting the attention of researchers and mental health professionals. Orthorexia nervosa (ON) is a possible new mental disorder, the main symptom of which is an obsessive and insecure focus on healthy foods and consequent compulsive behaviors. There is a common consensus among researchers that ON is considered partly overlapping with obsessive-compulsive disorders (OCDs). (2) Methods: MEDLINE and Scopus were searched for articles published in the last 10 years regarding the psychophysiological aspects of OCD and ON. Eight studies met the eligibility criteria. The inclusion criteria encompassed adults diagnosed with OCD and/or ON. However, only studies involving OCD patients were found. (3) Results: Some research groups have shown that OCD disorders can be considered among anxiety disorders because they are characterized by anxious hyper activation. Other research, however, has shown profiles characterized by low psychophysiological reactivity to stressful stimuli. Despite this, there seems to be a consensus on the poor inhibition abilities, even when activation is low, and the dissociation between cognitive and psychophysiological activation emerged. (4) Conclusions: However discordant, some points seem to bring the researchers to agreement. In fact, there is consensus on conducting a multidimensional assessment that can measure all of the aspects of suffering (cognition, emotion, and behavior) and highlight the poor body-mind integration. This clinical approach would make it possible to propose interventions aimed at treating some mental illnesses such as food obsession that can paradoxically impair the psychophysical balance. Nevertheless, the applied systematizing approach to existing studies on ON is very much needed for better understanding of the psychophysical nature of this new mental illness and its implications for prevention and treatment.

Effects of comorbid posttraumatic stress disorder on cognitive dysfunction in Chinese male methamphetamine patients

OBJECTIVES

Cognitive dysfunction and posttraumatic stress disorder (PTSD) are common in methamphetamine patients. However, few studies have investigated the cognitive performance of methamphetamine patients with PTSD. The purpose of this study was to investigate the impact of comorbid PTSD on cognitive function in Chinese male methamphetamine patients.

METHODS

We analyzed 464 methamphetamine patients and 156 healthy volunteers. The PTSD Screening Scale (PCL-5) was used to assess PTSD and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess cognitive function.

RESULTS

Compared with healthy controls, methamphetamine patients had more cognitive dysfunction in immediate memory, visuospatial/constructional, language, attention and delayed memory. Moreover, methamphetamine patients with PTSD had less cognitive dysfunction in immediate memory, attention, and delayed memory than methamphetamine patients without PTSD. Further stepwise regression analysis showed that PTSD alterations in arousal and reactivity cluster were risk predictors for language, and PTSD negative alteration in cognition and mood cluster were risk predictors for delayed memory.

CONCLUSIONS

Our results indicate that methamphetamine patients without PTSD have poorer cognitive dysfunction than those with PTSD. Some demographic and PTSD symptom clusters are protective or risk factors for cognitive dysfunction in methamphetamine patients.

Reduced working memory performance in PTSD and suicide among veterans presenting for treatment

Suicide is among the leading causes of death in the United States, underscoring the continued need to understand the mechanisms underlying suicide risk. A growing body of research has examined the role of working memory deficits in suicidal thoughts and behaviors (STBs), yet little research has evaluated putative pathways via which working memory impairments may heighten suicide risk. Elevated posttraumatic stress symptoms (PTSS) represent one plausible mechanism through which poor working memory performance may increase STBs. The present study utilized data from 140 treatment-seeking veterans who presented for an intake evaluation in the PTSD Clinical Team of a large VA Medical Center. Veterans completed self-report measures, a semi-structured PTSD evaluation, and a digit span working memory test. In addition to concurrent suicidal ideation assessed during the intake, additional information regarding past suicide attempts, presence of a safety plan, documentation of past suicidal behaviors, and engagement with suicide crisis lines were collected via electronic medical records. Consistent with hypotheses, a significant indirect path emerged such that poor working memory performance predicted greater suicidal ideation, greater likelihood of a past suicide attempt, and greater latent suicide risk via increased PTSS. However, no direct effect of working memory on STBs or indirect paths of PTSS on STBs via working memory emerged. These findings suggest that the relation between working memory and STBs may be explained by PTSS severity.

Escaping from worries: Comparing the effectiveness of focusing on one's breath, a neutral and a positive distractor in worry control

Focused-distraction strategies are commonly used for thought control, but their effectiveness in handling personal worries with different types of distractors has rarely been examined. To examine this issue, 101 undergraduate and graduate students whose depression levels fell below mild depression were recruited (64.4% female, M age  = 20.27) and were randomly assigned to one of the three strategy conditions: 34 participants for the focused-breathing strategy (FBS), 34 for the focused-positive-distractor strategy (FPS), and 33 for the focused-neutral-distractor strategy (FNS). After a short introduction and practice, they applied the assigned strategy during a 5-min worry control session to prevent thoughts regarding a recent worrying event. The number of worry intrusions was measured using an online self-caught method. Participants rated their emotional states before and after the worry control session. Their working memory capacities (WMCs) and depressive tendency were comparable across conditions. The results showed the FBS and FPS groups exhibited fewer worry intrusions than did the FNS group. Furthermore, worry intrusions were negatively related to WMC for the FNS group but independent of WMC for the other two. The above findings together indicate that the FBS and FPS are relatively effective and effortless methods for reducing worry intrusions. Negative emotions decreased after the worry control session for all groups. However, decoupling of negative emotions from worry intrusions was only observed for the FBS and FNS groups. Overall, FBS outperforms FPS and FNS in managing worries from the above aspects. Several theoretical and practical implications of the study were discussed.

Are failures to suppress obsessive-intrusive thoughts associated with working memory?

BACKGROUND AND OBJECTIVES

Obsessive compulsive disorder (OCD) is characterised by repeated attempts to suppress obsessive-intrusive thoughts (OITs). Nonclinical individuals also regularly engage in thought suppression. Attempts to suppress OITs are often unsuccessful and there is wide variation in suppression abilities across nonclinical and clinical samples. Understanding the mechanisms that explain variations in suppression abilities could enhance our understanding of OCD. This study aimed to investigate one potential mechanism - working memory - using a comprehensive thought suppression task.

METHODS

Eighty-three nonclinical participants completed a computerized thought dismissibility task (in which they replaced an obsessive-intrusive thought with a neutral thought), and a computerized working memory task. Participants also completed measures of OCD and negative mood.

RESULTS

None of the suppression variables (OIT frequency, mean OIT duration, mean latency to return, total OIT duration) were correlated with working memory capacity. Obsessive-compulsive symptoms were correlated with total OIT duration, but the relationship was not significant after controlling for negative mood.

LIMITATIONS

The thought dismissibility task does not account for differences in motivation to suppress OITs. The sample was non-clinical and mostly female.

CONCLUSION

An individual's ability to suppress OITs is not associated with their working memory capacity, suggesting poor working memory does not explain persistent OITs in individuals with OCD.

Association between spatial working memory and Re-experiencing symptoms in PTSD

BACKGROUND AND OBJECTIVES

Few studies have evaluated the link between working memory (WM) and post-traumatic stress disorder (PTSD). Further, it is unknown whether this relationship is accounted for by other relevant variables including negative affect, emotional dysregulation, or general non-WM-related cognitive control deficits, which are associated with PTSD. The purpose of this study was to determine the extent to which a computerized WM task could predict PTSD symptomology incrementally beyond the contribution of other relevant variables associated with PTSD.

METHODS

Thirty veterans were eligible to complete emotional symptom questionnaires, a heart-rate variability measure, and computerized tasks (i.e., emotional Stroop and automated complex span tasks). A three-stage hierarchical regression was conducted with the PCL-5 total score and symptom clusters (i.e., re-experiencing, avoidance, hyperarousal, and negative cognition/mood) as the dependent variable.

RESULTS

Results revealed that only the re-experiencing symptom cluster was significantly predicted by executive, verbal, and visuospatial WM tasks, which explained an additional 29.7% of the variance over and above other relevant variables. Most notably, the visuospatial task was the only WM task that significantly explained PCL-5 re-experiencing symptoms.

LIMITATIONS

This study was based on a small sample of veterans with PTSD and causality cannot be determined with this cross-sectional study.

CONCLUSIONS

Overall, the results suggest that deficits in visuospatial WM are significantly associated with PTSD re-experiencing symptoms after controlling for other relevant variables. Further research should evaluate whether an intervention to improve visuospatial WM capacity can be implemented to reduce re-experiencing symptoms.

Executive functioning deficits exacerbate posttraumatic stress symptoms: A longitudinal mediation model

Executive functioning (EF) consists of a set of related, but distinct, higher-level cognitive abilities that are used to organize and integrate lower-level processes in the service of engaging in goal-direct behavior. Evidence suggests that deficits in EF are a vulnerability factor for the development of posttraumatic stress (PTS) symptoms. Less understood, however, is the role that EF plays in symptom maintenance and exacerbation following trauma exposure. As such, the primary purpose of the present study was to determine whether EF deficits exacerbate PTS symptoms over the course of one year. A secondary aim of this study was to use a cross-lagged design to determine the directional relations among EF deficits and PTS. Trauma-exposed adults (N = 98) completed a clinical interview and self-report measures at an initial assessment session (Time 1 [T1]). Participants also completed self-report measures at 6- (Time 2 [T2]; n = 92) and 12-month (Time 3 [T3]; n = 91) follow-up sessions. As predicted, EF deficits at T2 mediated the relationship between PTS symptoms from T1 to T3, thus suggesting that EF deficits exacerbate PTS symptoms following trauma exposure. Results from a cross-lagged path analysis from T2 to T3 suggest that deficits in EF exert a stronger influence on the maintenance of PTS symptoms than vice versa. These results have implications for (a) identifying individuals that are at elevated risk for developing PTS symptoms, (b) developing precision medicine-based approaches for alleviating PTS symptoms, and (c) improving well-established PTSD treatments for those with relative deficits in EF.

Subjective Cognitive Decline Is More Accurate When Metamemory Is Better

Objective

Subjective cognitive decline (SCD) has emerged as one of the first manifestations of Alzheimer's disease (AD). However, discrepancies in its relationship with tests of memory and other cognitive abilities have hindered SCD's diagnostic utility. Inter-individual heterogeneity in metamemory, or memory awareness, and the use of clinical measures of cognition lacking sensitivity to early cognitive dysfunction, may contribute to these discrepancies. We aimed to assess if the relationship between SCD and markers of early cognitive dysfunction is moderated by metamemory abilities.

Methods

The sample included 79 cognitively healthy older adults (77% female, 68% White, and 32% Black participants) with a mean age of 74.4 (SD = 6.1) and 15.9 (SD = 2.7) years of education. Metamemory was assessed using an episodic Feeling of Knowing test with four 5-item trials. Outcome measures included a resolution metric defined as a gamma correlation reflecting the accuracy of item-level predictions ("Will you know the correct answer?"). Early cognitive dysfunction was measured through the Loewenstein-Acevedo Scale for Semantic Interference and Learning (LASSI-L) and the Short-Term Memory Binding Test (STMB), measures sensitive to preclinical AD. SCD was assessed with a 20-item questionnaire that asked participants to compare themselves to others their age on a 7-point Likert scale. Regression analyses examined whether a potential relation between SCD and early cognitive dysfunction was moderated by metamemory.

Results

Subjective cognitive decline was associated with susceptibility to semantic proactive interference such that greater complaints were associated with increased susceptibility to semantic proactive interference (b = -0.30, p = 0.003) only. Metamemory moderated the association between SCD and susceptibility to and recovery of semantic proactive interference such that those with more accurate metamemory showed a stronger association between increased complaints and susceptibility to semantic proactive interference (b = -0.71, p = 0.005; b = -0.62, p = 0.034). Metamemory, however, did not moderate the association of SCD with retroactive semantic interference nor short term memory binding.

Discussion

The accuracy of an individual's metamemory, specifically their ability to adjust moment to moment predictions in line with their performance, can influence the extent to which SCD maps onto objective cognition. Such self-referential assessment should be considered when interpreting SCD.

Improved Executive Functions and Reduced Craving in Youths with Methamphetamine Addiction: Evidence from Combined Transcranial Direct Current Stimulation with Mindfulness Treatment

OBJECTIVE

Transcranial direct current stimulation (tDCS) and mindfulness practices have been proposed as a potential approach to improve executive functions (EFs) and reduce craving in persons with substance use disorders. Based on the neural mechanisms of action of each of these interventions, the combination of both non-pharmacological interventions might have additive effects. In the current study, the effects of tDCS combined with mindfulness-based substance abuse treatment (MBSAT) to improve EFs and reduce craving were investigated in early abstinent methamphetamine abuse.

METHODS

Eighty (youths aged between 18 and 21) early-abstinent methamphetamine users were randomly assigned to the research groups (tDCS group [n = 20], mindfulness group [n = 20], combined mindfulness-tDCS group [n = 20], and sham group [n = 20]). Active tDCS (1.5 mA,20 min, 12 sessions) or sham tDCS was appliedover the left dorsolateral prefrontal cortex and the MBSAT protocol was used over twelve 50-min sessions.

RESULTS

Both in the post-test phase (immediately after the intervention) and follow-up phase (one month after the intervention), performance in most EFs tasks significantly improved in the combination group which received real tDCS ＋ MBSAT, as compared to baseline values and sham stimulation group. Similarly, a significant reduction in craving was observed after intervention inall treatment groups, but not the sham stimulation group. Interestingly, the increase in EFs and the reduction in craving post versus pre tDCS ＋ MBSAT intervention were correlated.

CONCLUSION

Findings from the current study provide initial support for the clinical effectiveness of combination tDCS ＋ MBSAT, possibly influencing cognitive/affective processes.

Cardiorespiratory fitness as protection against the development of memory intrusions: A prospective trauma analogue study

Intrusive and distressing memories are at the core of post-traumatic stress disorder (PTSD). Since cardiorespiratory fitness (CRF) has been linked with improved mental health, emotion regulation, and memory function, CRF may, by promoting these capabilities, protect against the development of intrusions after trauma. We investigated the CRF-intrusion relationship and its potential mediators in 115 healthy individuals, using a trauma film to induce intrusions. As potential mediators, we assessed indices of pre-trauma mental health such as heart rate variability, subjective and psychobiological peri-traumatic responses, and memory. Critically, results showed that higher CRF was related to fewer intrusions, but no mediators emerged for the CRF-intrusion relationship. These results indicate that individuals displaying higher CRF are less prone to develop traumatic memory intrusions. Future studies may want to investigate whether promoting fitness prior to possible trauma exposure can boost resilience against the development of debilitating re-experiencing symptoms of PTSD.

The Effectiveness of Mindfulness-Based-Stress-Reduction for Military Cadets on Perceived Stress

This study aimed to develop a program of mindfulness-based stress reduction for military cadets (MBSR-MC). On the basis of a pretest-posttest design, participants were assigned to either a control or an experimental group to examine the effectiveness of MBSR-MC. First, 60 volunteering cadets of National Defense University were randomly assigned to the MBSR-MC group (n = 30) and the control group (n = 30). In the pretest, all participants were required to complete the Taiwanese version of the Five Facet Mindfulness Questionnaire (T-FFMQ) and a perceived stress scale (PSS). Subsequently, the MBSR-MC group participated in the 8-week MBSR-MC program, whereas the control group did not receive any experimental treatment. One week following the completion of the program, a posttest consisted of the same questions as the pretest was conducted. Statistical analysis showed that (1) Comparing with the control group, the MBSR-MC group showed superior performance in three subscales of T-FFMQ, namely Acting with awareness, Non-judgment, and Non-reactivity. However, no significant difference was found in the remaining two facets: Observing and Describing. (2) The perceived stress score of the MBSR-MC group was significantly lower than that of the control group. Furthermore, an analysis of mediating effect showed that Acting with awareness, Non-judgment, and Non-reactivity were mediating variables of the relationship between MBSR-MC and perceived stress. The aforementioned results indicated that MBSR-MC training significantly increased military cadets' Acting with awareness, Non-judgment, and Non-reactivity, thereby significantly reducing their perceived stress. Therefore, this study supported the effectiveness of the MBSR-MC program on perceived stress.

Heightened risk of posttraumatic stress disorder in adults with autism spectrum disorder: The role of cumulative trauma and memory deficits

BACKGROUND

Individuals with Autism Spectrum Disorder (ASD) are known to be at increased risk of exposure to traumas such as maltreatment and abuse, however less is known about possible susceptibility towards the development of Posttraumatic Stress Disorder (PTSD) and associated risk factors.

AIMS

This study investigated the rates of trauma exposure and PTSD, and the role of cumulative trauma exposure and memory as risk factors for PTSD in adults who self-reported having received an ASD diagnosis, compared to a typically developing (TD) comparison group.

METHODS

Questionnaires assessing self-reported frequency of trauma exposure (LEC), PTSD symptomology (PCL-S) and memory (EMQ- R and BRIEF-A) were completed online by 38 ASD adults and 44 TD adults.

RESULTS

Rates of trauma exposure and PTSD symptomatology were significantly higher in the ASD group, compared to the TD group, with deficits in working memory and everyday memory mediating this association. Interestingly, a cumulative effect of trauma exposure on PTSD symptom severity was only found in the ASD group.

CONCLUSIONS

High rates of trauma and probable PTSD in ASD adults highlight the importance of routine screening. Cumulative trauma exposure and memory deficits may act to increase risk of PTSD in ASD; longitudinal research is called for.

Prospective associations between intelligence, working memory capacity, and intrusive memories of a traumatic film: Potential mediating effects of rumination and memory disorganization

BACKGROUND AND OBJECTIVES

Field research indicates that lower intelligence may predispose trauma-exposed individuals towards the development of re-experiencing symptoms. However, this assumption requires further testing in controlled prospective studies. In the current analog study, we tested whether lower fluid intelligence and lower working memory capacity (WMC) independently contribute to intrusion development. Moreover, we investigated potential mediating effects of trauma memory characteristics and trait rumination.

METHODS

118 healthy participants completed tests measuring fluid intelligence and WMC. Two days later, they were exposed to a film clip depicting traumatic events (i.e., so-called trauma film). After exposure to the film, intrusions were assessed using a diary and an intrusion triggering task.

RESULTS

Our analyses revealed a negative correlation between fluid intelligence and intrusions during the intrusion triggering task. WMC did not correlate with any intrusion measure. Moreover, planned analyses did not yield any mediation effects.

LIMITATIONS

We used the trauma film paradigm to examine analog posttraumatic stress symptoms. This approach limits the generalizability of our findings with regard to symptom development following real-life traumatic events.

CONCLUSIONS

Our results show for the first time that higher fluid intelligence is associated with fewer intrusions of a trauma film. This association was evident for laboratory but not for ambulatory intrusions. By demonstrating this association using a prospective experimental design, our study importantly corroborates previous field research.

Transcranial Direct Current Stimulation Improves Executive Dysfunctions in ADHD: Implications for Inhibitory Control, Interference Control, Working Memory, and Cognitive Flexibility

Objective: This study examined effects of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) on major executive functions (EFs), including response inhibition, executive control, working memory (WM), and cognitive flexibility/task switching in ADHD. Method: ADHD children received (a) left anodal/right cathodal DLPFC tDCS and (b) sham stimulation in Experiment 1 and (a) left anodal DLPFC/right cathodal OFC tDCS, (b) left cathodal DLPFC/right anodal OFC tDCS, and (c) sham stimulation in Experiment 2. The current intensity was 1 mA for 15 min with a 72-hr interval between sessions. Participants underwent Go/No-Go task, N-back test, Wisconsin Card Sorting Test (WCST), and Stroop task after each tDCS condition. Results: Anodal left DLPFC tDCS most clearly affected executive control functions (e.g., WM, interference inhibition), while cathodal left DLPFC tDCS improved inhibitory control. Cognitive flexibility/task switching benefited from combined DLPFC-OFC, but not DLPFC stimulation alone. Conclusion: Task-specific stimulation protocols can improve EFs in ADHD.

Creativity on demand - Hacking into creative problem solving

How can creative problem solving be enhanced? The paper identifies and examines modulatory approaches from the cognitive and neuroscientific literature that have been made to make creative problem solving better. We review neuromodulatory approaches of both global and local effects. Through a 2-process model of creative problem solving that involves both automatic and controlled processes, we demonstrate how these approaches could be used and what potential they may have for enhancing creative problem solving. We conclude that direct neuromodulation will be best used in unison with behavioral manipulations of cognition, and that better understanding of these manipulations should inform and guide research on direct neuromodulatory procedures.

Predictors of involuntary and voluntary emotional episodic memories of virtual reality scenarios in Veterans with and without PTSD

This study investigated predictors of involuntary and voluntary memories of stressful virtual reality scenarios. Thirty-two veterans of the two Persian Gulf Wars completed verbal memory tests and diagnostic assessments. They were randomly assigned to a Recounting (16) or a Suppression (16) condition. After immersion in the VR scenarios, the Recounting group described the scenarios and the Suppression group suppressed thoughts of the scenarios. One week later, participants completed surprise voluntary memory tests and another thought suppression task. The best predictors of voluntary memory were verbal memory ability, dissociation, and to a lesser extent, physiological arousal before and after scenarios. Dissociation and physiological stress responses selectively affected memory for neutral elements. Higher distress during scenarios impaired voluntary memory but increased the frequency of involuntary memories. Physiological stress responses promoted more frequent involuntary memories immediately after the scenarios. More frequent initial involuntary memories, tonic physiological arousal, and stronger emotional responses to dangerous events predicted difficulty inhibiting involuntary memories at follow-up. The effects of thought suppression were transient and weaker than those of other variables. The findings suggest that posttraumatic amnesia and involuntary memories of adverse events are more related to memory ability and emotional and physiological stress responses than to post-exposure suppression.

Arresting visuospatial stimulation is insufficient to disrupt analogue traumatic intrusions

Intrusive memories are a core symptom of Post-Traumatic Stress Disorder (PTSD). A growing body of analogue studies using trauma films suggest that carrying out specific demanding tasks (e.g., playing the video game Tetris, pattern tapping) after the analogue trauma can reduce intrusive memories. To examine the mechanism behind this effect, we tested whether mere engagement with attention-grabbing and interesting visual stimuli disrupts intrusive memories, and whether this depends on working memory resources and/or the concurrent activation of trauma film memories. In a total sample of 234 healthy participants, we compared no-task control conditions to a perceptual rating task with visually arresting video clips (i.e., non-emotional, complex, moving displays), to a less arresting task with non-moving, blurred pictures (Study 1), and to more demanding imagery tasks with and without repetitive reminders of the trauma film (Study 2). Generally, we found moderate to strong evidence that none of the conditions lead to differences in intrusion frequency. Moreover, our data suggest that intrusive memories were neither related to individual differences in working memory capacity (i.e., operation span performance; Study 1), nor to the degree of engagement with a visuospatial task (i.e., one-week recognition performance; Study 2). Taken together, our findings suggest that the boundary conditions for successful interference with traumatic intrusions may be more complex and subtle than assumed. Future studies may want to test the role of prediction errors during (re-)consolidation, deliberate efforts to suppress thoughts, or the compatibility of the task demands with the individual's skills.

Weaker Memory Performance Exacerbates Stress-Induced Cannabis Craving in Youths' Daily Lives

Theories of addiction posit that stimuli associated with drug use, including both exteroceptive (e.g., paraphernalia) and interoceptive (e.g., feeling tense or "stressed"), evoke craving and contribute to the pathogenesis of substance misuse. Control over drug cue response and stress is essential for moderating use. Building from laboratory data supporting associations between cue exposure, stress, and craving, this study tested whether these associations generalize to real-world settings and examined whether a well-vetted neurocognitive control capacity, i.e., working memory (WM), moderated associations. Youth (N = 85; 15-24 years) completed baseline and ecological momentary assessments. Cue exposure and participants' average stress predicted higher craving. Youth with weaker WM experienced stronger craving at higher-stress moments but not when faced with cues. Interactions were present for both previous-moment and same-moment stress. Craving among adolescents with stronger WM was not swayed by momentary stress. Findings suggest stronger WM protects against craving at more stressful moments.

Low working memory capacity in euthymic bipolar I disorder: No relation to reappraisal on emotion regulation

BACKGROUND

Emotion regulation (ER) applies behavioral and cognitive strategies to modify the appearance and intensity of emotions. Working memory capacity (WMC) plays an important role in the ER process, particularly through its influence on the efficiency of ER strategies.

METHODS

We investigated interactions between WMC and three ER strategies, namely cognitive reappraisal, expressive suppression, and rumination, in 43 euthymic patients with bipolar I disorder and 48 healthy control subjects. We used the Korean versions of the Operation Span Task, Emotion Regulation Questionnaire, Ruminative Response Scale, and Difficulties in Emotion Regulation Scale.

RESULTS

WMC modulated the efficacy of cognitive reappraisal in healthy controls with high WMC, but not in patients with bipolar disorder. There were no significant interactions between WMC and expressive suppression or rumination in either group.

LIMITATIONS

These include the small sample size, use of neutral words to evaluate negative emotion, use of self-administered questionnaires, and relatively high cut-off for the definition of euthymic states. A number of uncontrolled factors may have influenced our results including patients' duration of remission, number of episodes, psychiatric family history, and current psychiatric medications.

CONCLUSIONS

Our findings suggest that working memory does not function effectively in the reappraisal process during ER in patients with bipolar disorder. This may indicate that top-down regulation of emotion is impaired in bipolar disorder. Cognitive interventions aimed at improving ER in such patients may be ineffective.

Neural mechanisms of internal distraction suppression in visual attention

When performing a demanding cognitive task, internal distraction in the form of task-irrelevant thoughts and mind wandering can shift our attention away from the task, negatively affecting task performance. Behaviorally, individuals with higher executive function indexed by higher working memory capacity (WMC) exhibit less mind wandering during cognitive tasks, but the underlying neural mechanisms are unknown. To address this problem, we recorded functional magnetic resonance imaging (fMRI) data from subjects performing a cued visual attention task, and assessed their WMC in a separate experiment. Applying machine learning and time-series analysis techniques, we showed that (1) higher WMC individuals experienced lower internal distraction through stronger suppression of posterior cingulate cortex (PCC) activity, (2) higher WMC individuals had better neural representations of attended information as evidenced by higher multivoxel decoding accuracy of cue-related activities in the dorsal attention network (DAN), (3) the positive relationship between WMC and DAN decoding accuracy was mediated by suppression of PCC activity, (4) the dorsal anterior cingulate (dACC) was a source of top-down signals that regulate PCC activity as evidenced by the negative association between Granger-causal influence dACC→PCC and PCC activity levels, and (5) higher WMC individuals exhibiting stronger dACC→PCC Granger-causal influence. These results shed light on the neural mechanisms underlying the executive suppression of internal distraction in tasks requiring externally oriented attention and provide an explanation of the individual differences in such suppression.

Investigating the effect of proactive interference control training on intrusive memories

Intrusive re-experiencing is a hallmark symptom of Posttraumatic Stress Disorder (PTSD). According to prominent models of intrusive phenomena, intrusive memories may result from impairments in the efficiency of working memory capacity (WMC), more specifically proactive interference control. Yet, experimental research is scarce. Therefore, the present study aimed to investigate experimentally the role of proactive interference control in intrusive memories. We randomly assigned 57 healthy participants to either receive a high interference control training or a low interference control training. Participants were then exposed to highly distressing film clips. WMC was assessed before and after the training. Intrusion symptoms were assessed directly post-training and after one week using an Intrusion Provocation Task (IPT), a one-week intrusions diary, and the retrospective intrusion subscale of the Impact of Event Sale - Revised (IES-R). Results indicated that both groups reported improvements in WMC and fewer intrusions on the second IPT post-training, with no differences between groups. Similarly, no group differences on intrusions were found at one-week follow-up (i.e., intrusion diary and IES-R). To conclude, these data are not consistent with the hypothesis that WMC plays a role in intrusive re-experiencing. Implications for future research are discussed.

Melatonin ameliorates cognitive memory by regulation of cAMP-response element-binding protein expression and the anti-inflammatory response in a rat model of post-traumatic stress disorder

BACKGROUND

Post-traumatic stress disorder (PTSD) is an important psychological disease that can develop following the physical experience or witnessing of traumatic events. The psychopathological response to traumatic stressors increases inflammation in the hippocampus and induces memory deficits. Melatonin (MTG) plays critical roles in circadian rhythm disorders, Alzheimer's disease, and other neurological disorders. However, the cognitive efficiency of MTG and its mechanisms of action in the treatment of PTSD remain unclear. Thus, the present study investigated the effects of MTG on spatial cognitive impairments stimulated by single prolonged stress (SPS) in rats, an animal model of PTSD. Male rats received intraperitoneal (i.p.) administration of various doses of MTG for 21 consecutive days after the SPS procedure.

RESULTS

SPS-stimulated cognitive impairments in the object recognition task and Morris water maze were reversed by MTG treatment (25 mg/kg, i.p). Additionally, MTG significantly increased cognitive memory-related decreases in cAMP-response element-binding (CREB) protein and mRNA levels in the hippocampus. Our results also demonstrate that MTG significantly inhibited SPS-stimulated cognitive memory impairments by inhibiting the expression of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in the rat brain.

CONCLUSION

The present results indicate that MTG can be beneficial for SPS-stimulated memory impairments via changes in CREB expression and proinflammatory mediators. Thus, MTG may be a prophylactic strategy for the prevention or mitigation of the progression of some features of the PTSD pathology.

Treatment of post-traumatic psychiatric disorders: A continuum of immediate, post-immediate and follow-up care mediated by specific psychotherapeutic principles. Clinical experience in French-speaking countries

BACKGROUND

People who witness a horrific event are at risk of suffering from acute psychological disorders, potentially leading to chronic post-traumatic symptoms and severe medico-psycho-social complications. Traumatised individuals suffer from psychological damage that is initially indescribable: they are often unable to ask for care in the immediate aftermath of an event. Afterwards, traumatic events and their post-traumatic consequences are still often hidden or minimised by patients for reasons linked to the disorder itself (inexpressibility, shame, depressive thoughts, fear of stigmatisation, etc.). The provision of the initial stage of care has a major impact on the long-term prognosis. Although official French recommendations remain vague, and scientific studies lack power, there is a developing professional consensus on practices, and developments in neurobiology are opening up new opportunities to validate them.

OBJECTIVE

Drawing upon our clinical experience and clinical principles provided by our mentors, our aim is to clarify the phases of psychotherapeutic treatment, and we describe three practices: immediate care ("defusing"), post-immediate care ("French debriefing" or "post-immediate psychotherapeutic intervention") and follow-up care ("deferred debriefing" and psychotherapy). Although the international literature considers these phases as separate, here we describe a continuity of talking therapies that support long-term remission.

RESULTS

The effectiveness of the combination of immediate, post-immediate and follow-up care has been confirmed by events surrounding the recent Paris and Nice attacks. Specific psychotherapeutic principles are unrelated to a particular school of psychotherapy (notably cognitive and behavioural therapies, analytical therapies, various forms of hypnosis, and eye-movement therapies, etc.). Instead, they refer to specific principles that are effective in the treatment of post-traumatic psychiatric disorders. By helping the individual to verbalise their experience, talking re-establishes dissociated psychological functions. A process of reconsolidation enables sensory memory to be integrated into verbal memory. Supported by psychotherapy, language can be used to discover, or construct, a new sense of meaning for the individual.

CONCLUSION

A single session of post-immediate or deferred debriefing has been found to have a miraculous effect on post-traumatic symptoms, confirmed by follow-up. When disorders are chronic and complex, however, treatment can last several months or years. In each case, although certain therapeutic principles are key, other psychotherapeutic and pharmacological treatments should be adapted to the individual's clinical situation, and the symptoms they present.

An unpleasant emotional state reduces working memory capacity: electrophysiological evidence

Emotional states can guide the actions and decisions we make in our everyday life through their influence on cognitive processes such as working memory (WM). We investigated the long-lasting interference that an unpleasant emotional state had on goal-relevant WM representations from an electrophysiological perspective. Participants performed a change detection task that was preceded by the presentation of unpleasant or neutral task-irrelevant pictures in a blocked fashion. We focused on the contralateral delay activity (CDA), an event-related potential that is sensitive to the number of task-relevant items stored in WM. We found that the asymptotic limit for the CDA amplitude was lower during the unpleasant emotional state than during the neutral one; that is, an emotional state was capable of reducing how many task-relevant items the participants could hold in WM. Furthermore, both the individuals who experienced more intrusive thoughts and those who were dispositionally anxious were more susceptible to the influence of the emotional state. We provide evidence that an unpleasant emotional state diminished visual WM for task-relevant items, particularly in susceptible individuals. These results open new avenues to uncover the emotional-cognitive processing that underlies maladaptive WM representations and the role of such processing in the development of mental illness.

Working memory cannot regulate overt emotional capture

Individual differences in working memory capacity partly arise from variability in attention control, a process influenced by negative emotional content. Thus, individual differences in working memory capacity should predict differences in the ability to regulate attention in emotional contexts. To address this hypothesis, a complex-span working memory task was modified so that negative arousing images or neutral images subtended the background during the encoding phase. Across three experiments, negative arousing images impaired working memory encoding relative to neutral images, resulting in impoverished symmetry span scores. Contrary to the primary hypothesis, individual differences in working memory capacity derived from three complex span tasks failed to moderate the effect of negative arousing images on working memory encoding across two large scale studies. Additionally, in Experiment 3, both negative and arousing images captured attention and were processed despite their incongruence with task goals which led to increased memory for the images in a subsequent recognition task. Implications for theories of working memory and attention control in emotional contexts will be discussed.

Individual variation in working memory is associated with fear extinction performance

PTSD has been associated consistently with abnormalities in fear acquisition and extinction learning and retention. Fear acquisition refers to learning to discriminate between threat and safety cues. Extinction learning reflects the formation of a new inhibitory-memory that competes with a previously learned threat-related memory. Adjudicating the competition between threat memory and the new inhibitory memory during extinction may rely, in part, on cognitive processes such as working memory (WM). Despite significant shared neural circuits and signaling pathways the relationship between WM, fear acquisition, and extinction is poorly understood. Here, we analyzed data from a large sample of healthy Marines who underwent an assessment battery including tests of fear acquisition, extinction learning, and WM (N-back). Fear potentiated startle (FPS), fear expectancy ratings, and self-reported anxiety served as the primary dependent variables. High WM ability (N = 192) was associated with greater CS + fear inhibition during the late block of extinction and greater US expectancy change during extinction learning compared to individuals with low WM ability (N = 204). WM ability was not associated with magnitude of fear conditioning/expression. Attention ability was unrelated to fear acquisition or extinction supporting specificity of WM associations with extinction. These results support the conclusion that individual differences in WM may contribute to regulating fear responses.

Neural mechanisms of interference control in working memory capacity

The extent to which one can use cognitive resources to keep information in working memory is known to rely on (1) active maintenance of target representations and (2) downregulation of interference from irrelevant representations. Neurobiologically, the global capacity of working memory is thought to depend on the prefrontal and parietal cortices; however, the neural mechanisms involved in controlling interference specifically in working memory capacity tasks remain understudied. In this study, 22 healthy participants completed a modified complex working memory capacity task (Reading Span) with trials of varying levels of interference control demands while undergoing functional MRI. Neural activity associated with interference control demands was examined separately during encoding and recall phases of the task. Results suggested a widespread network of regions in the prefrontal, parietal, and occipital cortices, and the cingulate and cerebellum associated with encoding, and parietal and occipital regions associated with recall. Results align with prior findings emphasizing the importance of frontoparietal circuits for working memory performance, including the role of the inferior frontal gyrus, cingulate, occipital cortex, and cerebellum in regulation of interference demands.

Successfully controlling intrusive memories is harder when control must be sustained

After unpleasant events, people often experience intrusive memories that undermine their peace of mind. In response, they often suppress these unwanted memories from awareness. Such efforts may fail, however, when inhibitory control demands are high due to the need to sustain control, or when fatigue compromises inhibitory capacity. Here we examined how sustained inhibitory demand affected intrusive memories in the Think/No-Think paradigm. To isolate intrusions, participants reported, trial-by-trial, whether their preceding attempt to suppress retrieval had triggered retrieval of the memory they intended to suppress. Such counter-intentional retrievals provide a laboratory model of the sort of involuntary retrieval that may underlie intrusive memories. Using this method, we found that longer duration trials increased the probability of an intrusion. Moreover, on later No-Think trials, control over intrusions suddenly declined, with longer trial durations triggering more relapses of items that had been previously been purged. Thus, the challenges of controlling retrieval appear to cause a decline in control over time, due to a change in state, such as fatigue. These findings raise the possibility that characteristics often true of people with psychiatric disorders - such as compromised sleep, and increased demand on control - may contribute to difficulties in suppressing intrusive memories.

Examining procedural working memory processing in obsessive-compulsive disorder

Previous research has suggested that a deficit in working memory might underlie the difficulty of obsessive-compulsive disorder (OCD) patients to control their thoughts and actions. However, a recent meta-analyses found only small effect sizes for working memory deficits in OCD. Recently, a distinction has been made between declarative and procedural working memory. Working memory in OCD was tested mostly using declarative measurements. However, OCD symptoms typically concerns actions, making procedural working-memory more relevant. Here, we tested the operation of procedural working memory in OCD. Participants with OCD and healthy controls performed a battery of choice reaction tasks under high and low procedural working memory demands. Reaction-times (RT) were estimated using ex-Gaussian distribution fitting, revealing no group differences in the size of the RT distribution tail (i.e., τ parameter), known to be sensitive to procedural working memory manipulations. Group differences, unrelated to working memory manipulations, were found in the leading-edge of the RT distribution and analyzed using a two-stage evidence accumulation model. Modeling results suggested that perceptual difficulties might underlie the current group differences. In conclusion, our results suggest that procedural working-memory processing is most likely intact in OCD, and raise a novel, yet untested assumption regarding perceptual deficits in OCD.