Individual differences in the encoding of contextual details following acute stress:An explorative study

Information processing under stressful circumstances depends on many experimental conditions, like the information valence or the point in time at which brain function is probed. This also holds true for memorizing contextual details (or 'memory contextualization'). Moreover, large interindividual differences appear to exist in (context-dependent) memory formation after stress, but it is mostly unknown which individual characteristics are essential. Various characteristics were explored from a theory-driven and data-driven perspective, in 120 healthy men. In the theory-driven model, we postulated that life adversity and trait anxiety shape the stress response, which impacts memory contextualization following acute stress. This was indeed largely supported by linear regression analyses, showing significant interactions depending on valence and time point after stress. Thus, during the acute phase of the stress response, reduced neutral memory contextualization was related to salivary cortisol level; moreover, certain individual characteristics correlated with memory contextualization of negatively valenced material: (a) life adversity, (b) alpha-amylase reactivity in those with low life adversity and (c) cortisol reactivity in those with low trait anxiety. Better neutral memory contextualization during the recovery phase of the stress response was associated with (a) cortisol in individuals with low life adversity and (b) alpha-amylase in individuals with high life adversity. The data-driven Random Forest-based variable selection also pointed to (early) life adversity-during the acute phase-and (moderate) alpha-amylase reactivity-during the recovery phase-as individual characteristics related to better memory contextualization. Newly identified characteristics sparked novel hypotheses about non-anxious personality traits, age, mood and states during retrieval of context-related information

Resting-state functional connectivity in combat veterans suffering from impulsive aggression

Impulsive aggression is common among military personnel after deployment and may arise because of impaired top-down regulation of the amygdala by prefrontal regions.This study sought to further explore this hypothesis via resting-state functional connectivity analyses in impulsively aggressive combat veterans. Male combat veterans with (n¼28) and without (n¼30) impulsive aggression problems underwent resting-state functional magnetic resonance imaging. Functional connectivity analyses were conducted with the following seed-regions: basolateral amygdala (BLA), centromedial amygdala, anterior cingulate cortex (ACC), and anterior insular cortex (AIC). Regions-of-interest analyses focused on the orbitofrontal cortex and periaqueductal gray, and yielded no significant results. In exploratory cluster analyses, we observed reduced functional connectivity between the (bilateral) BLA and left dorsolateral prefrontal cortex in the impulsive aggression group, relative to combat controls. This finding indicates that combat-related impulsive aggression may be marked by weakened functional connectivity between the amygdala and prefrontal regions, already in the absence of explicit emotional stimuli. Group differences in functional connectivity were also observed between the (bilateral) ACC and left cuneus, which may be related to heightened vigilance to potentially threatening visual cues, as well as between the left AIC and right temporal pole, possibly related to negative memory association in impulsive aggression

Time-dependent effects of psychosocial stress on the contextualization of neutral memories

Memories about stressful experiences need to be both specific and generalizable to adequately guide future behavior. Memory strength is influenced by emotional significance, and contextualization (i.e., encoding experiences with their contextual details) enables selective context-dependent retrieval and protects against overgeneralization. The current randomized-controlled study investigated how the early and late phase of the endogenous stress response affects the contextualization of neutral and negative information. One hundred healthy male participants were randomly divided into three experimental groups that performed encoding either 1) without stress (control), 2) immediately after acute stress (early) or 3) two hours after acute stress (late). Stress was induced via the Trier Social Stress Test and salivary alpha-amylase and cortisol levels were measured throughout the experiment. In the Memory Contextualization Task, neutral and angry faces (items) were depicted against unique context pictures during encoding. During testing 24 h later, context-dependent recognition memory of the items was assessed by presenting these in either congruent or incongruent contexts (relative to encoding). Multilevel analyses revealed that neutral information was more contextualized when encoding took place two hours after psychosocial stress, than immediately after the stressor. Results suggest that the late effects in the unique, time-dependent sequence of a healthy endogenous stress response, could complement reduced contextualization immediately after stress. The contextualization of negative information was not influenced by psychosocial stress, as opposed to earlier reported effects of exogenous hydrocortisone administration. An imbalance between the early and late effects of the endogenous stress response could increase vulnerability for stress-related psychopathology.</p

No Time-Dependent Effects of Psychosocial Stress on Fear Contextualization and Generalization:A Randomized-Controlled Study With Healthy Participants

The formation of context-dependent fear memories (fear contextualization) can aid the recognition of danger in new, similar, situations. Overgeneralization of fear is often seen as hallmark of anxiety and trauma-related disorders. In this randomized-controlled study, we investigated whether exposure to a psychosocial stressor influences retention of fear contextualization and generalization in a time-dependent manner. The Trier Social Stress Test was used to induce psychosocial stress. Healthy male participants (n = 117) were randomly divided into three experimental groups that were subjected to the acquisition phase of the Fear Generalization Task: (1) without stress, (2) immediately after acute stress, or (3) 2 h after acute stress. In this task, a male with neutral facial expression (conditioned stimuli) was depicted in two different contexts that modulated the conditioned stimuli–unconditioned stimuli (=shock) association (threat, safe). Salivary alpha-amylase and cortisol levels were measured throughout the experiment. After a 24-h delay, context-dependency of fear memory was investigated with an unannounced memory test consisting of the threat and safe contexts alternated with a novel context (the generalization context). Multilevel analyses revealed that participants showed increased fear-potentiated startle responses to the conditioned stimuli in the threat compared to the safe context, at the end of the acquisition phase, indicating adequate fear contextualization. Directly after acquisition, there were no time-dependent effects of psychosocial stress on fear contextualization. Context-dependency of fear memories was retained 24 h later, as fear-potentiated startle responding was modulated by context (threat > safe or novel). At that time, the context-dependency of fear memories was also not influenced by the early or late effects of the endogenous stress response during acquisition. These results with experimental stress deviate in some aspects from those earlier obtained with exogenous hydrocortisone administration, suggesting a distinct role for stress mediators other than cortisol

Pattern classification based on the amygdala does not predict an individual's response to emotional stimuli

Functional magnetic resonance imaging (fMRI) studies have often recorded robust univariate group effects in the amygdala of subjects exposed to emotional stimuli. Yet it is unclear to what extent this effect also holds true when multi-voxel pattern analysis (MVPA) is applied at the level of the individual participant. Here we sought to answer this question. To this end, we combined fMRI data from two prior studies (N = 112). For each participant, a linear support vector machine was trained to decode the valence of emotional pictures (negative, neutral, positive) based on brain activity patterns in either the amygdala (primary region-of-interest analysis) or the whole-brain (secondary exploratory analysis). The accuracy score of the amygdala-based pattern classifications was statistically significant for only a handful of participants (4.5%) with a mean and standard deviation of 37% ± 5% across all subjects (range: 28–58%; chance-level: 33%). In contrast, the accuracy score of the whole-brain pattern classifications was statistically significant in roughly half of the participants (50.9%), and had an across-subjects mean and standard deviation of 49% ± 6% (range: 33–62%). The current results suggest that the information conveyed by the emotional pictures was encoded by spatially distributed parts of the brain, rather than by the amygdala alone, and may be of particular relevance to studies that seek to target the amygdala in the treatment of emotion regulation problems, for example via real-time fMRI neurofeedback training.publishedVersio

Compassion apps for better mental health: qualitative review

Background There is increasing empirical evidence for the positive mental health effects of compassion-based interventions. Although numerous smartphone apps offering compassion-based interventions (‘compassion apps’) are now available for the general public, the quality of these apps has not yet been reviewed. A qualitative review of existing compassion apps serves as a crucial first step toward testing the efficacy of these apps, by identifying good-quality compassion apps that might be worth the investment of a scientific trial. Aims The current study focuses on reviewing the quality of existing compassion apps. Method Existing compassion apps were identified through searches in the Google Play Store and App Store. The 24 included apps were reviewed on their quality by using the Mobile App Rating Scale, and on their consistency with current evidence by comparing them to existing and studied compassion-based interventions. Results Of the 24 included apps, eight were identified that met the criteria of being consistent with existing and studied compassion-based interventions, and acceptable to good overall quality. The other 16 apps failed to meet one or both of these criteria. Conclusions Good-quality compassion apps are available, but many of the available apps fail to meet certain quality criteria. In particular, many apps failed to offer sufficient relevant and correct information, or failed to offer this information in an entertaining and interesting way. It is recommended that future compassion apps are based on a clear definition of compassion, offer evidence- and theory-based exercises and implement tools for increasing engagement

Seeking treatment for mental illness and substance abuse:A cross-sectional study on attitudes, beliefs, and needs of military personnel with and without mental illness

Background Often, military personnel do not seek treatment for mental illness or wait until they reach a crisis point. Effective, selective, and indicated prevention is best achieved by seeking treatment early. Aims We aimed to examine military personnel's attitudes, beliefs, and needs around seeking treatment for mental illness. We compared those who sought treatment to those who did not and those with and without the intention to seek treatment. Finally, we examined factors associated with intentions of not seeking treatment. Method We conducted a cross-sectional questionnaire study of military personnel with (N = 324) and without (N = 554) mental illness. Descriptive and regression analyses (logistic and ordinal) were performed. Results The majority of the personnel believed treatment was effective (91.6%); however, most preferred to solve their own problems (66.0%). For personnel with mental illness, compared to those who sought treatment, those who did not had a higher preference for self-management and found advice from others less important. For those without mental illness, those with no intention to seek treatment indicated a higher preference for self-management, stigma-related concerns, denial of symptoms, lower belief in treatment effectiveness and found it less important to be an example, compared to those with treatment-seeking intentions. A clear indication of where to seek help was the most reported need (95.7%). Regression analyses indicated that not seeking treatment was most strongly related to preference for self-management (OR(95%CI) = 4.36(2.02–9.39); no intention to seek treatment was most strongly related to a lower belief that treatment is effective (OR(95%CI) = .41(0.28–0.59) and with not having had positive earlier experiences with treatment seeking (OR(95%CI) = .34(0.22–0.52). Conclusions To facilitate (early) treatment seeking, interventions should align with a high preference for self-management, mental illness stigma should be targeted, and a clear indication of where to seek treatment is needed

Mental health issues and illness and substance use disorder (non-)disclosure to a supervisor:A cross-sectional study on beliefs, attitudes and needs of military personnel

Objectives Research suggests that military personnel frequently delay disclosing mental health issues and illness (MHI), including substance use disorder, to supervisors. This delay causes missed opportunities for support and workplace accommodations which may help to avoid adverse occupational outcomes. The current study aims to examine disclosure-related beliefs, attitudes and needs, to create a better understanding of personnel’s disclosure decision making.Design A cross-sectional questionnaire study among military personnel with and without MHI. Beliefs, attitudes and needs regarding the (non-)disclosure decision to a supervisor were examined, including factors associated with (non-)disclosure intentions and decisions. Descriptive and regression (logistic and ordinal) analyses were performed.Setting The study took place within the Dutch military.Participants Military personnel with MHI (n=324) and without MHI (n=554) were participated in this study.Outcome measure (Non-)disclosure intentions and decisions.Results Common beliefs and attitudes pro non-disclosure were the preference to solve one’s own problems (68.3%), the preference for privacy (58.9%) and a variety of stigma-related concerns. Common beliefs and attitudes pro disclosure were that personnel wanted to be their true authentic selves (93.3%) and the desire to act responsibly towards work colleagues (84.5%). The most reported need for future disclosure (96.8%) was having a supervisor who shows an understanding for MHI. The following factors were associated both with non-disclosure intentions and decisions: higher preference for privacy (OR (95% CI))=(1.99 (1.50 to 2.65)intention, 2.05 (1.12 to 3.76)decision) and self-management (OR (95% CI))=(1.64 (1.20 to 2.23)intention, 1.79 (1.00 to 3.20)decision), higher stigma-related concerns (OR (95% CI))=(1.76 (1.12 to 2.77)intention, 2.21 (1.02 to 4.79)decision) and lower quality of supervisor–employee relationship (OR (95% CI))=(0.25 (0.15 to 0.42)intention, 0.47 (0.25 to 0.87)decision).Conclusion To facilitate (early-)disclosure to a supervisor, creating opportunities for workplace support, interventions should focus on decreasing stigma and discrimination and align with personnels’ preference for self-management. Furthermore, training is needed for supervisors on how to recognise, and effectively communicate with, personnel with MHI. Focus should also be on improving supervisor–employee relationships

Regions of white matter abnormalities in the arcuate fasciculus in veterans with anger and aggression problems

Aggression after military deployment is a common occurrence in veterans. Neurobiological research has shown that aggression is associated with a dysfunction in a network connecting brain regions implicated in threat processing and emotion regulation. However, aggression may also be related to deficits in networks underlying communication and social cognition. The uncinate and arcuate fasciculi are integral to these networks, thus studying potential abnormalities in these white matter connections can further our understanding of anger and aggression problems in military veterans. Here, we use diffusion tensor imaging tractography to investigate white matter microstructural properties of the uncinate fasciculus and the arcuate fasciculus in veterans with and without anger and aggression problems. A control tract, the parahippocampal cingulum was also included in the analyses. More specifically, fractional anisotropy (FA) estimates are derived along the trajectory from all fiber pathways and compared between both groups. No between-group FA differences are observed for the uncinate fasciculus and the cingulum, however parts of the arcuate fasciculus show a significantly lower FA in the group of veterans with aggression and anger problems. Our data suggest that abnormalities in arcuate fasciculus white matter connectivity that are related to self-regulation may play an important role in the etiology of anger and aggression in military veterans

Effects of tDCS during inhibitory control training on performance and PTSD, aggression and anxiety symptoms: a randomized-controlled trial in a military sample

Background: Post-traumatic stress disorder (PTSD), anxiety, and impulsive aggression are linked to transdiagnostic neurocognitive deficits. This includes impaired inhibitory control over inappropriate responses. Prior studies showed that inhibitory control can be improved by modulating the right inferior frontal gyrus (IFG) with transcranial direct current stimulation (tDCS) in combination with inhibitory control training. However, its clinical potential remains unclear. We therefore aimed to replicate a tDCS-enhanced inhibitory control training in a clinical sample and test whether this reduces stress-related mental health symptoms. Methods: In a preregistered double-blind randomized-controlled trial, 100 active-duty military personnel and post-active veterans with PTSD, anxiety, or impulsive aggression symptoms underwent a 5-session intervention where a stop-signal response inhibition training was combined with anodal tDCS over the right IFG for 20 min at 1.25 mA. Inhibitory control was evaluated with the emotional go/no-go task and implicit association test. Stress-related symptoms were assessed by self-report at baseline, post-intervention, and after 3-months and 1-year follow-ups. Results: Active relative to sham tDCS neither influenced performance during inhibitory control training nor on assessment tasks, and did also not significantly influence self-reported symptoms of PTSD, anxiety, impulsive aggression, or depression at post-assessment or follow-up. Conclusions: Our results do not support the idea that anodal tDCS over the right IFG at 1.25 mA enhances response inhibition training in a clinical sample, or that this tDCS-training combination can reduce stress-related symptoms. Applying different tDCS parameters or combining tDCS with more challenging tasks might provide better conditions to modulate cognitive functioning and stress-related symptoms