Association between neuroticism and amygdala responsivity emerges under stressful conditions

An Honest Reckoning With the Amygdala and Mental Illness

Anxiety disorders are a leading source of human misery, morbidity, and premature mortality. Existing treatments are far from curative for many, underscoring the need to clarify the underlying neural mechanisms. Although many brain regions contribute, the amygdala has received the most intense scientific attention. Over the past several decades, this scrutiny has yielded a detailed understanding of amygdala function, but it has failed to produce new clinical assays, biomarkers, or cures. Rising to this urgent public health challenge demands an honest reckoning with the functional-neuroanatomical complexity of the amygdala and a shift from theories anchored on "the amygdala" to models centered on specific amygdala nuclei and cell types. This review begins by examining evidence from studies of rodents, monkeys, and humans for the "canonical model," the idea that the amygdala plays a central role in fear- and anxiety-related states, traits, and disorders. Next, the authors selectively highlight work indicating that the canonical model, while true, is overly simplistic and fails to adequately capture the actual state of the evidentiary record, the breadth of amygdala-associated functions and illnesses, or the complexity of the amygdala's functional architecture. The authors describe the implications of these facts for basic and clinical neuroimaging research. The review concludes with some general recommendations for grappling with the complexity of the amygdala and accelerating efforts to understand and more effectively treat amygdala-related psychopathology.

Pharmacotherapeutic strategies for the treatment of anorexia nervosa - novel targets to break a vicious cycle

INTRODUCTION

Anorexia nervosa (AN) has one of the highest mortality rates of all mental illnesses. No approved pharmacological treatments exist for AN, but novel neurobiological targets show promise.

AREAS COVERED

Studies show that in individuals with AN, there are alterations in brain neurotransmitter signaling, alongside associated mental rigidity and comorbid anxiety and depression. Available and new therapies could be used to improve alterations in neurobiology and behavior. This narrative review serves as a review of previously published literature assessing the efficacy of traditional pharmacotherapy in treating AN while also exploring novel treatments, including dissociative anesthetics, psychedelics, cannabinoids, hormones, neurosteroids, and ketogenic nutrition.

EXPERT OPINION

If best practice psychotherapeutic interventions have failed, we recommend a neuroscience and brain research-based medication approach that targets dopamine neurotransmitter receptors to enhance cognitive flexibility and illness insight while reducing dread and avoidance toward food. It is furthermore essential to recognize and treat comorbid conditions such as anxiety, depression, or obsessive-compulsive disorder as they interfere with recovery, and typically do not resolve even with successful AN treatment. Novel strategies have the promise to show efficacy in improving mood and reducing specific AN psychopathology with hopes to be used in clinical practice soon.

Transdiagnostic phenomena of psychopathology in the context of the RDoC: protocol of a multimodal cross-sectional study

In the past, affective and cognitive processes related to psychopathology have been examined within the boundaries of phenotype-based diagnostic labels, which has led to inconsistent findings regarding their underlying operating principles. Investigating these processes dimensionally in healthy individuals and by means of multiple modalities may provide additional insights into the psychological and neuronal mechanisms at their core. The transdiagnostic phenomena Neuroticism and Rumination are known to be closely linked. However, the exact nature of their relationship remains to be elucidated. The same applies to the associations between Hedonic Capacity, Negativity Bias and different Emotion Regulation strategies.This multimodal cross-sectional study examines the relationship of the transdiagnostic phenomena Neuroticism and Rumination as well as Hedonic Capacity, the Negativity Bias and Emotion Regulation from a RDoC (Research Domain Criteria) perspective. A total of 120 currently healthy subjects (past 12 months) will complete several questionnaires regarding personality, emotion regulation, hedonic capacity, and psychopathologies as well as functional magnetic resonance imaging (fMRI) during cognitive and emotional processing, to obtain data on the circuit, behavioral and self-report level.This study aims to contribute to the understanding of the relationship between cognitive and affective processes associated with psychopathologies as well as their neuronal correlates. Ultimately, a grounded understanding of these processes could guide improvement of diagnostic labels and treatments. Limitations include the cross-sectional design and the limited variability in psychopathology scores due to the restriction of the sample to currently healthy subjects.

Relationships between diversity demographics, psychological distress, and suicidal thinking in the veterinary profession: a nationwide cross-sectional study during COVID-19

Purpose

This study aimed to determine the relationship between demographic diversity and veterinary professionals regarding their psychological distress and suicidal experiences. This study also aimed to determine what demographic factors were associated with psychological distress and suicidal experiences for veterinary professionals.

Methods

This study used a cross-sectional web-based questionnaire to assess the prevalence of diversity, psychological distress, and suicidality in individuals over 18 working in the veterinary field within the United States. The study received 2,482 responses resulting in 2,208 responses that were included in the analysis. Descriptive statistics were performed to identify the categories with the highest rates of psychological distress, suicidal thoughts, and suicidal behaviors. Binomial logistic regressions were conducted to identify the strongest statistical predictors of psychological distress (Kessler-6-K6), suicidal thinking and suicide behaviors.

Results

Of the 2,208 respondents included in the analysis, 888 (41%) were experiencing serious psychological distress and 381 (17.3%) had considered suicide in the past 12 months. Results of the binomial regressions indicate gender, social class, age, and disability status were the strongest predictors of psychological distress. When controlling for psychological distress, the strongest predictors of suicidal thinking were sexual orientation, marital status, and professional role.

Implications

Limited research has been done to explore the relationship between demographic diversity of veterinary professionals and psychological distress, suicidal thoughts, and suicidal behaviors specifically. These results shed light on multiple demographic factors that promote and attenuate mental health, as well as the importance of asking respondents their demographic identities in veterinary medicine research. This research attempts to identify these mental health factors without collapsing categories with small sample sizes, which does cause a limitation in statistical power, yet also demonstrates how to increase inclusivity in research.

Psychological implications of humane endings on the veterinary profession

The veterinary profession has a unique responsibility to animals during the final stages of their lives. The veterinarian's obligations extend to humane endings, involving all species of animals in a range of circumstances including, but not limited to, euthanasia of individually owned animals, euthanasia of animals for research purposes, depopulation of animals during emergencies, and slaughter of animals raised for food. The veterinary profession continues to improve animal welfare through advances in end-of-life decision-making and humane killing techniques,1-3 but the psychological impacts on veterinarians have not received the same level of consideration. Building on the influential AVMA Humane Endings Guideline, the AVMA recognizes that support for the mental health of veterinarians engaged in such activities needs to be a priority. This article aims to provide the foundation and rationale for improved preparation and establishment of sustainable mental health resources and to offer recommendations on pragmatic solutions to support and prepare veterinary professionals as leaders impacted by participation in humane endings-related activities. While end-of-life decision-making and implementation may present mental health challenges to veterinarians, it is crucial to recognize that there are stressors specific to each situation and that every individual's experience is valid. Addressing the mental health issues surrounding the decision-making process and implementation of humane endings activities start with a comprehensive understanding of each activity's unique context and the veterinarian's leadership role. Therefore, this article highlights the psychological impact of depopulation and its similarities and exclusive challenges compared with euthanasia and humane slaughter.

Trait anxiety is associated with amygdala expectation and caloric taste receipt response across eating disorders

Anxious traits are elevated in eating disorders (EDs), are considered risk factors for ED development, and trait anxiety has been linked to ED psychopathology. How trait anxiety relates to ED neurobiology is not well understood. In this study 197 individuals across the ED spectrum (anorexia nervosa n = 91; other specified EDs n = 34; bulimia nervosa n = 56; binge ED n = 16), and 120 healthy controls were assessed for anxious traits and learned to expect and receive caloric or neutral taste stimuli during brain imaging. Amygdala sucrose expectation response differed across groups (Wilk's lambda = 0.945, p = 0.023), and was higher on the left in anorexia nervosa compared to healthy controls (p = 0.002). Expected sucrose receipt response across taste reward regions was not different between groups. In the ED sample, trait anxiety negatively moderated the relationship between amygdala expectation and right dorsal (p = 0.0062) and ventral (p = 0.0046) anterior insula receipt response. A subgroup analysis showed similar results for anorexia nervosa, and partially in bulimia nervosa. Across EDs, appetitive motivation correlated positively with bilateral orbitofrontal cortex, caudate head, and ventral striatal sucrose receipt response (r = 0.215 to 0.179, p = 0.002 to 0.012). Across the study sample, trait anxiety showed an inverted-U-shaped relationship with right (r = 0.147, p = 0.034) and left (r = 0.162, p = 0.016) amygdala expectation response. Amygdala sucrose expectation response is elevated in anorexia nervosa, correlates with sucrose receipt response, and this relationship is negatively moderated by trait anxiety across EDs. Trait anxiety may have an important role in how expectation drives taste stimulus receipt brain response and perhaps food approach in individuals with EDs.

Personality traits affect anticipatory stress vulnerability and coping effectiveness in occupational critical care situations

The present study aimed at investigating the influence of personality on both anticipatory stress vulnerability and the effectiveness of coping strategies in an occupational stressful context. Following assessment of individual personality traits (Big Five Inventory), 147 volunteers were exposed to the anticipation of a stressful event. Anxiety and cardiac reactivity were assessed as markers of vulnerability to anticipatory stress. Participants were then randomly assigned to three groups and subjected to a 5-min intervention: relaxation breathing, relaxation breathing combined with cardiac biofeedback, and control. The effectiveness of coping interventions was determined through the cardiac coherence score achieved during the intervention. Higher neuroticism was associated with higher anticipatory stress vulnerability, whereas higher conscientiousness and extraversion were related to lower anticipatory stress vulnerability. Relaxation breathing and biofeedback coping interventions contributed to improve the cardiac coherence in all participants, albeit with greater effectiveness in individuals presenting higher score of openness to experience. The present findings demonstrated that personality traits are related to both anticipatory stress vulnerability and effectiveness of coping interventions. These results bring new insights into practical guidelines for stress prevention by considering personality traits. Specific practical applications for health professionals, who are likely to manage stressful situations daily, are discussed.

Amygdala reactivity during socioemotional processing and cortisol reactivity to a psychosocial stressor

Threat-related amygdala reactivity and the activation of the Hypothalamic-Pituitary-Adrenal (HPA) axis have been linked to negative psychiatric outcomes. The amygdala and HPA axis have bidirectional connections, suggesting that functional variation in one system may influence the other. However, research on the functional associations between these systems has demonstrated mixed findings, potentially due to small sample sizes and cortisol sampling and data analytic procedures that investigate only pre-post differences in cortisol rather than the specific phases of the cortisol stress response. Further, previous research has primarily utilized samples of adults of mostly European descent, limiting generalizability to those of other ethnoracial identities and ages. Therefore, studies addressing these limitations are needed in order to investigate the functional relations between amygdala reactivity to threat and HPA axis stress responsivity. Using a sample of 159 adolescents from a diverse cohort (75% African American, ages 15-17 years), the present study evaluated associations between amygdala reactivity during socioemotional processing using fMRI and HPA axis reactivity to a socially-evaluative cold pressor task. Greater amygdala activation to fearful and neutral faces was associated with greater cortisol peak values and steeper activation slope. As cortisol peak values and cortisol activation slope capture the intensity of the cortisol stress response, these data suggest that greater activation of the amygdala in response to social distress and ambiguity among adolescents may be related to hyper-reactivity of the HPA axis.

The Stressful Personality: A Meta-Analytical Review of the Relation Between Personality and Stress

The current study presented the first meta-analytic review on the associations between the Big Five personality traits and stress measured under different conceptualizations (stressor exposure, psychological and physiological stress responses) using a total of 1,575 effect sizes drawn from 298 samples. Overall, neuroticism was found to be positively related to stress, whereas extraversion, agreeableness, conscientiousness, and openness were negatively linked to stress. When stress assessed under different conceptualizations was tested, only neuroticism, agreeableness, and conscientiousness were related to stressor exposure. All of the Big Five personality traits were significantly associated with psychological stress perception, whereas the five personality traits showed weak to null associations with physiological stress response. Further moderation analyses suggested that the associations between personality traits and stress under different conceptualizations were also contingent upon different characteristics of stress, sample, study design, and measures. The results supported the important role of personality traits in individual differences in stress.

Neurite density imaging in amygdala nuclei reveals interindividual differences in neuroticism

Neuroticism is known to have significant health implications. While previous research revealed that interindividual differences in the amygdala function are associated with interindividual differences in neuroticism, the impact of the amygdala’s structure and especially microstructure on variations in neuroticism remains unclear. Here, we present the first study using NODDI to examine the association between the in vivo microstructural architecture of the amygdala and neuroticism at the level of neurites. We, therefore, acquired brain images from 221 healthy participants using advanced multi‐shell diffusion‐weighted imaging. Because the amygdala comprises several nuclei, we, moreover, used a high‐resolution T1 image to automatically segment the amygdala into eight different nuclei. Neuroticism and its facets have been assessed using the NEO‐PI‐R. Finally, we associated neuroticism and its facets with the volume and microstructure of the amygdala nuclei. Statistical analysis revealed that lower neurite density in the lateral amygdala nucleus (La) was significantly associated with higher scores in depression, one of the six neuroticism facets. The La is the sensory relay of the amygdala, filtering incoming information based on previous experiences. Reduced neurite density and related changes in the dendritic structure of the La could impair its filtering function. This again might cause harmless sensory information to be misevaluated as threatening and lead to the altered amygdala responsivity as reported in previous studies investigating the functional correlates of neuroticism and neuroticism‐related disorders like depression.

Mild early-life stress exaggerates the impact of acute stress on corticolimbic resting-state functional connectivity

Abundant evidence shows that early‐life stress (ELS) predisposes for the development of stress‐related psychopathology when exposed to stressors later in life, but the underlying mechanisms remain unclear. To study predisposing effects of mild ELS on stress sensitivity, we examined in a healthy human population the impact of a history of ELS on acute stress‐related changes in corticolimbic circuits involved in emotional processing (i.e., amygdala, hippocampus and ventromedial prefrontal cortex [vmPFC]). Healthy young male participants (n = 120) underwent resting‐state functional magnetic resonance imaging (fMRI) in two separate sessions (stress induction vs. control). The Childhood Trauma Questionnaire (CTQ) was administered to index self‐reported ELS, and stress induction was verified using salivary cortisol, blood pressure, heart rate and subjective affect. Our findings show that self‐reported ELS was negatively associated with baseline cortisol, but not with the acute stress‐induced cortisol response. Critically, individuals with more self‐reported ELS exhibited an exaggerated reduction of functional connectivity in corticolimbic circuits under acute stress. A mediation analysis showed that the association between ELS and stress‐induced changes in amygdala–hippocampal connectivity became stronger when controlling for basal cortisol. Our findings show, in a healthy sample, that the effects of mild ELS on functioning of corticolimbic circuits only become apparent when exposed to an acute stressor and may be buffered by adaptations in hypothalamic–pituitary–adrenal axis function. Overall, our findings might reveal a potential mechanism whereby even mild ELS might confer vulnerability to exposure to stressors later in adulthood.

Is neuroticism really bad for you? Dynamics in personality and limbic reactivity prior to, during and following real-life combat stress

The personality trait of neuroticism is considered a risk factor for stress vulnerability, putatively via its association with elevated limbic reactivity. Nevertheless, majority of evidence to date that relates neuroticism, neural reactivity and stress vulnerability stems from cross-sectional studies conducted in a “stress-free” environment. Here, using a unique prospective longitudinal design, we assessed personality, stress-related symptoms and neural reactivity at three time points over the course of four and a half years; accounting for prior to, during, and long-time following a stressful military service that included active combat. Results revealed that despite exposure to multiple potentiality traumatic events, majority of soldiers exhibited none-to-mild levels of posttraumatic and depressive symptoms during and following their military service. In contrast, a quadratic pattern of change in personality emerged overtime, with neuroticism being the only personality trait to increase during stressful military service and subsequently decrease following discharge. Elevated neuroticism during military service was associated with reduced amygdala and hippocampus activation in response to stress-related content, and this association was also reversed following discharge. A similar pattern was found between neuroticism and hippocampus-anterior cingulate cortex (ACC) functional connectivity in response to stress-related content. Taken together these findings suggest that stressful military service at young adulthood may yield a temporary increase in neuroticism mediated by a temporary decrease in limbic reactivity, with both effects being reversed long-time following discharge. Considering that participants exhibited low levels of stress-related symptoms throughout the study period, these dynamic patterns may depict behavioral and neural mechanisms that facilitate stress resilience.

Neuroticism and reward-related ventral striatum activity: Probing vulnerability to stress-related depression

Elevated neuroticism may confer vulnerability to the depressogenic effects of stressful life events (SLEs). However, the mechanisms underlying this susceptibility remain poorly understood. Accumulating evidence suggests that stress-related disruptions in neural reward processing might undergird links between stress and depression. Using data from the Saint Louis Personality and Aging Network (SPAN) study and Duke Neurogenetics Study (DNS), we examined whether neuroticism moderates links between stressful life events (SLE) and depression as well as SLEs and ventral striatum (VS) response to reward. In the longitudinal SPAN sample (n = 971 older adults), SLEs prospectively predicted future depressive symptoms, especially among those reporting elevated neuroticism, even after accounting for prior depressive symptoms and previous SLE exposure (NxSLE interaction: p = .016, ΔR² = 0.003). Cross-sectional analyses of the DNS, a young adult college sample with neuroimaging data, replicated this interaction (n = 1,343: NxSLE interaction: p = .019, ΔR² = 0.003) and provided evidence that neuroticism moderates the association between SLEs and reward-related VS response (n = 1,195, NxSLE: p = .017, ΔR² = 0.0048). Blunted left VS response to reward was associated with a lifetime depression diagnosis, r = -0.07, p = .02, but not current depressive symptoms, r = -0.003, p = .93. These data suggest that neuroticism may promote vulnerability to stress-related depression and that sensitivity to stress-related reductions in VS response may be a potential neural mechanism underlying vulnerability to clinically significant depression. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The brain under stress-A systematic review and activation likelihood estimation meta-analysis of changes in BOLD signal associated with acute stress exposure

Psychosocial stress is an omnipresent phenomenon whose neural correlates in humans are still poorly understood. Several paradigms have been developed to induce acute stress in fMRI settings, but it is unclear whether there is a global brain activation pattern related to psychosocial stress. To integrate the different neuronal activation patterns, we conducted an activation likelihood estimation analysis on 31 studies totaling 1279 participants. Studies used the ScanSTRESS, Montreal Imaging Stress Test, aversive viewing paradigm (AVP), Social-Evaluative Threat or Cyberball. The analysis revealed bilateral activation clusters comprising the claustrum, insula and inferior frontal gyrus. This indicates that exposure to psychosocial stress leads to activations in brain areas involved in affective processing and the endocrine stress response. Furthermore, in a systematic review, Cyberball and AVP presented themselves as outliers due to increased activation in motor areas and lack of induction of stress related activity changes, respectively. As different paradigms emphasize different dimensions of psychosocial stress such as social evaluation or performance pressure, future research is needed to identify differences between the paradigms.

The Dynamics of Personality Approach (DPA): 20 Tenets for Uncovering the Causal Mechanisms of Personality

Over the last few decades, most personality psychology research has been focused on assessing personality via scores on a few broad traits and investigating how these scores predict various behaviours and outcomes. This approach does not seek to explain the causal mechanisms underlying human personality and thus falls short of explaining the proximal sources of traits as well as the variation of individuals’ behaviour over time and across situations. On the basis of the commonalities shared by influential process–oriented personality theories and models, we describe a general dynamics of personality approach (DPA). The DPA relies heavily on theoretical principles applicable to complex adaptive systems that self–regulate via feedback mechanisms, and it parses the sources of personality in terms of various psychological functions relevant in different phases of self–regulation. Thus, we consider personality to be rooted in individual differences in various cognitive, emotional–motivational, and volitional functions, as well as their causal interactions. In this article, we lay out 20 tenets for the DPA that may serve as a guideline for integrative research in personality science. © 2020 The Authors. European Journal of Personality published by John Wiley & Sons Ltd on behalf of European Association of Personality Psychology

Better Safe Than Sorry: A Common Signature of General Vulnerability for Psychopathology

Several labels, such as neuroticism, negative emotionality, and dispositional negativity, indicate a broad dimension of psychopathology. However, largely separate, often disorder-specific research lines have developed that focus on different cognitive and affective characteristics that are associated with this dimension, such as perseverative cognition (worry, rumination), reduced autobiographical memory specificity, compromised fear learning, and enhanced somatic-symptom reporting. In this article, we present a theoretical perspective within a predictive-processing framework in which we trace these phenotypically different characteristics back to a common underlying “better-safe-than-sorry” processing strategy. This implies information processing that tends to be low in sensory-perceptual detail, which allows threat-related categorical priors to dominate conscious experience and for chronic uncertainty/surprise because of a stagnated error-reduction process. This common information-processing strategy has beneficial effects in the short term but important costs in the long term. From this perspective, we suggest that the phenomenally distinct cognitive and affective psychopathological characteristics mentioned above represent the same basic processing heuristic of the brain and are only different in relation to the particular type of information involved (e.g., in working memory, in autobiographical memory, in the external and internal world). Clinical implications of this view are discussed.

From Description to Explanation: Integrating Across Multiple Levels of Analysis to Inform Neuroscientific Accounts of Dimensional Personality Pathology

Dimensional approaches to psychiatric nosology are rapidly transforming the way researchers and clinicians conceptualize personality pathology, leading to a growing interest in describing how individuals differ from one another. Yet, in order to successfully prevent and treat personality pathology, it is also necessary to explain the sources of these individual differences. The emerging field of personality neuroscience is well-positioned to guide the transition from description to explanation within personality pathology research. However, establishing comprehensive, mechanistic accounts of personality pathology will require personality neuroscientists to move beyond atheoretical studies that link trait differences to neural correlates without considering the algorithmic processes that are carried out by those correlates. We highlight some of the dangers we see in overpopulating personality neuroscience with brain-trait associational studies and offer a series of recommendations for personality neuroscientists seeking to build explanatory theories of personality pathology.

Spontaneous microstates related to effects of low socioeconomic status on neuroticism

Individuals with high neuroticism had the decreased control functions of anterior cingulate cortex (ACC) over amygdala (emotion regions) and low socioeconomic status (SES) had negative effects on the functions of ACC. Based on these, we hypothesized that the decreased functions of ACC might make individuals with low SES had high level of neuroticism. According to the score of objective SES (OSES) and subjective SES (SSES) scales, subjects were divided into four groups (low SSES, high SSES, low OSES and high OSES) to investigate the roles of dynamic characteristics related to the ACC in the relationships between SES and neuroticism using resting-state EEG (RS-EEG) microstates analysis. It had been found that RS-EEG microstates can be divided into four types (MS1, MS2, MS3 and MS4) and the MS3 was related cingulo-opercular brain networks (including ACC and anterior insular). As our prediction, SSES had direct effects on neuroticism relative to OSES. Moreover, the neuroticism for low SSES was positively related to the occurrence and contribution of MS3, as well as the possibilities of transitions between MS3 and MS1. Based on these, we thought that low-SSES individuals might be more difficult to inhibit the negative emotions, especially inhibit the spontaneous thoughts related to these emotions.

The Role of Personality, Political Attitudes and Socio-Demographic Characteristics in Explaining Individual Differences in Fear of Coronavirus: A Comparison Over Time and Across Countries

Since the emergence of the SARS-CoV-2 pandemic in December 2019 about 500,000 people died within the first 6 months. The virus itself, as well as the related political decisions, intensified an increasing feeling of fear in billions of people worldwide. However, while some people remained unperturbed, others experienced panic over the current situation. In order to investigate individual differences in the perceptions, emotions and behaviors in response to the Coronavirus pandemic, an online survey was conducted between 6th and 27th of March 2020. Participants included 7309 individuals from 96 countries, who provided information on socio-demographics, personality, political orientation and general life satisfaction. To determine the specificity of fear of Coronavirus, we also investigated fear related to two other current political issues: the refugee and the climate crises. Overall, in parallel with the escalation of the pandemic, fear of Coronavirus increased significantly over the 22-day period, with the strongest predictors being the personality variable neuroticism, as well as education, sex and being an at-risk person. A detailed longitudinal analysis of the largest sample, Germany, revealed that political orientation was also an important predictor of fear of Coronavirus. Specifically, conservatives were more afraid of Coronavirus than liberals. However, as the perceived threat of the virus increased, the influence of political orientation disappeared, whereas personality remained a stable predictor. The pattern of results regarding the perceived threat of the refugee and climate crises painted a different picture: political orientation was by far the best predictor, more important even than personality. Conservatives were more worried about the refugees, and liberals about climate change. Cross-cultural analyses showed pronounced differences between countries, dependent on the crisis. Nonetheless, the importance of personality for the prediction of fear of Coronavirus remained stable over time and across the world within the investigated 22-day period.

Endogenous cortisol-related alterations of right anterior insula functional connectivity under acute stress

BACKGROUND

Previous studies have suggested that the right anterior insula (rAI) plays a vital role in salience processing and stress-related disorders. In this study, we aimed to investigate the relationship between rAI functional connectivity changes and individual differences in cortisol responses after acute stress, in order to provide insights into psychiatric illness vulnerabilities.

METHODS

Thirty-five young men were enrolled in a randomized, counterbalanced two-session study, with aversive movie clip combined with electrical shocks as stress stimulation and the neutral movie clip as control stimulation. Resting-state fMRI data was acquired after movie exposure. The rAI was chosen as seed for functional connectivity analysis. We then examined the effect of acute stress on rAI functional connectivity and its association with individuals' cortisol response.

RESULTS

We found decreased rAI functional connectivity in the fronto-parietal regions, but increased functional connectivity in the visual and somatosensory areas following acute stress. Moreover, stress-induced cortisol response was significantly positively correlated with the rAI functional connectivity in the medial prefrontal cortex, and negatively correlated with the orbital-frontal cortex, lingual gyrus, and middle temporal gyrus.

LIMITATIONS

Only young Chinese males without any trauma experience were recruited in this study.

CONCLUSIONS

The results suggested tight link between specific rAI functional connectivity alterations and individual stress reactivity, which may help elucidate the potential neurobiological mechanism underlying vulnerability to stress-related disorders.

Structural equation modeling of the associations between amygdala activation, personality, and internalizing, externalizing symptoms of psychopathology

There is an expanding literature on the theoretical and empirical connections between personality and psychopathology, and their shared neurobiological correlates. Recent cybernetic theories of personality and psychopathology, as well as affective neuroscience theory, provide grounding for understanding neurobiological-personality-psychopathology (NPP) associations. With the emergence of large sample datasets (e.g., Human Connectome Project) advanced quantitative modeling can be used to rigorously test dynamic statistical representations of NPP connections. Also, research suggests that these connections are influenced by sex, and large samples provide the opportunity to examine how NPP associations might be moderated by sex. The current study used a large sample from the Duke Neurogenetics Study (DNS) to examine how amygdala activation to facial expressions was linked with self-report of personality traits and clinical interviews of internalizing and externalizing symptoms of psychopathology. Structural equation modeling results revealed direct associations of amygdala activation with personality trait expression, as well as indirect associations (though personality) with symptoms of psychopathology. Moreover, the NPP links were moderated by sex. The current results are in line with research that identifies a broader role played by the amygdala in personality and provide potential insights for continued research in personality neuroscience and recent theories on the neurobiology of personality.

The effect of final dissertation defense language, native vs. non-native, in the psychophysiological stress response of university students

The objective of this study was to analyze the effect of final dissertation defense language in the autonomic stress response and cortical arousal of Physiotherapy students. We analysed in 110 students divided in 2 groups: native language (83) and non-native language (27), the autonomic stress response in four different moments of the dissertation defense; the cortical arousal and subjective perception of distress before and after the dissertation; and academic performance perception of students and the real performance obtained. Results showed a high sympathetic modulation at the beginning of the evaluation, which was maintained until the end of the evaluation in both groups. In addition, no decrease in cortical activity was found, possibly due to the short time of exposure to the stressful event. The final dissertation defense of Physiotherapy students produces an anticipatory anxiety response and a maintained high sympathetic nervous system activation during the defense, not negatively affecting cortical arousal, regardless of defending in native or non-native language.

Good vibrations: An observational study of real-life stress induced by a stage performance

Stressors induce physiological changes in the brain and periphery that support adaptive defensive responses. The consequences of psychological stress on cognitive functioning are often measured in laboratory settings using experimentally induced stress that leads to mainly negative subjective feelings. There is a need for verification of these studies using real-life stressors that may potentially induce both positive and negative subjective feelings. In an observational study, we investigated real-life stress induced by voluntary stage performance at a large-scale music festival, including 126 participants (60 female, age range = 16-57 years). Our primary measurements involved salivary cortisol, heart rate, blood pressure, and positive and negative affect. In addition, participants completed a 2-back working memory task and a speeded decision-making task. We found that stage performance significantly increased salivary cortisol - with a particularly low number of cortisol non-responders - and heart rate, even when controlling for potential confounding factors, such as sleep, movement, and alcohol use. Interestingly, stage performance significantly decreased negative affect while increasing positive affect. This positively experienced stressor ("eustressor") was related to impaired working memory performance: the stronger the increases in cortisol, the slower participants responded to targets. Decision-making, however, was not affected. In conclusion, we show how stressful experiences in real-life can lead to positive affect, but still have a similar negative impact on cognitive functioning. We suggest that future research should focus more on the consequences of real-life stressors, and the consequences of eustress, in order to extend our understanding of the concept of psychological stress.

Neuroticism modulates neural activities of posterior cingulate cortex and thalamus during psychosocial stress processing

OBJECTIVE

Individuals with higher neuroticism are vulnerable to stress and are prone to develop depression, however, the neural mechanisms underlying it have not been clarified clearly.

METHOD

The Montreal Imaging Stress Task (MIST) was administered to 148 healthy adults during functional magnetic resonance imaging (fMRI). Whole-brain voxel-wise regression analyses were used to detect associations of neuroticism with neural activity involved in perceiving and processing psychosocial stress. In addition, two-sample t-tests were conducted between the high-neurotic and low-neurotic group in order to supplement the results found in regression analyses.

RESULTS

Higher neuroticism scores were associated with higher activities in the posterior cingulate cortex (PCC)/precuneus and thalamus (p < 0.05, false discovery rate correction). Moreover, two sample t-tests also revealed that the high-neurotic group had higher neural stress responses in precuneus and bilateral thalamus in comparison to the low-neurotic group (p < 0.05, false discovery rate correction).

LIMITATIONS

Our study mainly recruited young adults, which may limit the generalizability of our findings.

CONCLUSIONS

Our findings highlight the crucial role of PCC/precuneus and thalamus in the association between neuroticism and stress and may provide insight into the cognitive model of depression.

Improved quality of life and reduced depressive symptoms in medical students after a single-session intervention

OBJECTIVE

Anxiety and depression are prevalent among medical students. Brazilian medical students have higher levels of depression and lower quality of life than their U.S. counterparts, and no preventive intervention exists for this risk group in Brazil. The Unified Protocol for Transdiagnostic Treatment of Emotional Disorders (UP), a cognitive-behavioral treatment protocol for neuroticism, was recently adapted into a single-session, preventive intervention. This study tested the impact of this protocol on psychiatric symptoms and quality of life in Brazilian medical students.

METHODS

In this open trial, the intervention protocol was translated and adapted to Brazilian Portuguese. Medical students over 18 years of age without psychotic symptoms, severe depressive episodes, or acute psychiatric risk were included, undergoing a psychiatric clinical interview (Mini-International Neuropsychiatric Interview [MINI]) and evaluation at baseline and at 7 and 30 days after a single-session UP that included experimental avoidance, quality of life, self-esteem, empathy, and anxiety symptom scales. A new evaluation was performed 90 days after the intervention.

RESULTS

Sixty-two students participated. Ninety days after the intervention, there were significant reductions in the number of students who met the criteria for social anxiety disorder (p = 0.013) or panic disorder (p = 0.001). There were also significant improvements in depressive symptoms (Beck Depression Inventory, p < 0.001) and quality of life (Quality of Life Enjoyment and Satisfaction Questionnaire, p < 0.001).

CONCLUSION

UP improved anxiety and depressive symptoms in medical students. The single-session group format could reduce costs and facilitate application. Future placebo-controlled studies are necessary to confirm these findings.

Prefrontal cortex activity triggered by affective faces exposure and its relationship with neuroticism

The emotional processing of affective faces is an essential element of social relationships. Individual differences in personality traits such as neuroticism can influence how we manage these interactions. The objective of this study was to analyze changes in prefrontal cortex (PFC) activity in response to visual exposure to affective faces, and to ascertain whether changes in PFC activity were related to scores in neuroticism, including depression, anxiety, low self-esteem and dependence facets. Fifty-two healthy undergraduate female students participated in the present study. Results showed significant differences depending on face valence in the left and right ventrolateral PFC. We found a reduction in oxygen consumption in reaction to neutral and happy faces, and a small increase in oxygenation in reaction to angry faces both in the left and the right PFC. There were significant positive correlations in the left ventrolateral PFC between oxygenation changes during exposure to neutral and happy faces and the neuroticism factor. Anxiety and depression facets showed positive significant correlations with oxygenation changes for all Time blocks. Notice that participants with high neuroticism scores did not show differences in ventrolateral PFC activity depending on face valence. We suggest that PFC would play a protective role in response to emotional stimuli. The reduced regulatory control of PFC over the amygdala could explain vulnerability to emotional disorders in subjects with high neuroticism.

Neuroticism Modulates the Functional Connectivity From Amygdala to Frontal Networks in Females When Avoiding Emotional Negative Pictures

Amygdala activity was previously found to correlate with neuroticism as an effect of valence, but so far few studies have focused on motivational context. The network subserving altered amygdala activity has not yet been investigated although some studies showed strong effective connections with prefrontal cortex (PFC). The goal of this study was to test the modulatory role of neuroticism on the functional connectivity (FC) between amygdala and other brain regions, especially PFC, during emotion processing from motivational direction. We applied an emotional picture viewing paradigm with different motivational directions (approaching and avoiding) in a large participant sample. The results showed that neuroticism predicted the amount of amygdala FC to dorsomedial PFC (dmPFC) and middle cingulate cortex (MCC). Increased FC during negative vs. positive pictures was found primarily in low neuroticism subjects, especially during the avoid condition. This valence and motivation dependent connectivity increase were disrupted for high neurotic participants. No effect of neuroticism was found for the approach condition. We showed that neuroticism, especially in the context of passive affect regulation, may have impaired connectivity between amygdala and putative regulatory cortical networks.

Childhood trauma history is linked to abnormal brain connectivity in major depression

Patients with major depressive disorder (MDD) present with heterogeneous symptom profiles, while neurobiological mechanisms are still largely unknown. Brain network studies consistently report disruptions of resting-state networks (RSNs) in patients with MDD, including hypoconnectivity in the frontoparietal network (FPN), hyperconnectivity in the default mode network (DMN), and increased connection between the DMN and FPN. Using a large, multisite fMRI dataset (n = 189 patients with MDD, n = 39 controls), we investigated network connectivity differences within and between RSNs in patients with MDD and healthy controls. We found that MDD could be characterized by a network model with the following abnormalities relative to controls: (i) lower within-network connectivity in three task-positive RSNs [FPN, dorsal attention network (DAN), and cingulo-opercular network (CON)], (ii) higher within-network connectivity in two intrinsic networks [DMN and salience network (SAN)], and (iii) higher within-network connectivity in two sensory networks [sensorimotor network (SMN) and visual network (VIS)]. Furthermore, we found significant alterations in connectivity between a number of these networks. Among patients with MDD, a history of childhood trauma and current symptoms quantified by clinical assessments were associated with a multivariate pattern of seven different within- and between-network connectivities involving the DAN, FPN, CON, subcortical regions, ventral attention network (VAN), auditory network (AUD), VIS, and SMN. Overall, our study showed that traumatic childhood experiences and dimensional symptoms are linked to abnormal network architecture in MDD. Our results suggest that RSN connectivity may explain underlying neurobiological mechanisms of MDD symptoms and has the potential to serve as an effective diagnostic biomarker.

Dispositional negativity, cognition, and anxiety disorders: An integrative translational neuroscience framework

When extreme, anxiety can become debilitating. Anxiety disorders, which often first emerge early in development, are common and challenging to treat, yet the underlying mechanisms have only recently begun to come into focus. Here, we review new insights into the nature and biological bases of dispositional negativity, a fundamental dimension of childhood temperament and adult personality and a prominent risk factor for the development of pediatric and adult anxiety disorders. Converging lines of epidemiological, neurobiological, and mechanistic evidence suggest that dispositional negativity increases the likelihood of psychopathology via specific neurocognitive mechanisms, including attentional biases to threat and deficits in executive control. Collectively, these observations provide an integrative translational framework for understanding the development and maintenance of anxiety disorders in adults and youth and set the stage for developing improved intervention strategies.

Neuroticism modulates mood responses to pharmacological sex hormone manipulation in healthy women

BACKGROUND

Women show increased risk of depressive symptoms during hormonal transition phases. The risk mechanisms may include changes in mood in response to fluctuating ovarian hormones moderated by predisposing risk factors for mood disorders, such as personality trait Neuroticism.

METHODS

A pooled sample of 92 mentally healthy women (28.3 ± 7.1, mean age ± SD) from two independent cohorts run in our lab, using gonadotropin-releasing hormone agonist (GnRHa) experimentally (n = 28) compared to placebo (n = 27) and as part in vitro fertilization (n = 37), were extracted from the Center for Integrated Molecular Brain Imaging database. All women filled in questionnaires of trait Neuroticism from the NEO personality Inventory-Revised (NEO PI-R) at baseline and self-reported levels of mood disturbances with the Profile of Mood States (POMS) daily during 14 days of GnRHa intervention or placebo. Effects of intervention by trait Neuroticism on serial daily reports of mood disturbances were examined using mixed model analyses.

RESULTS

Personality trait Neuroticism significantly modulated daily mood responses to GnRHa, but not placebo. Women with high and low scores on trait Neuroticism at baseline experienced more pronounced changes in mood when exposed to GnRHa, whereas women with medium trait Neuroticism scores remained relatively stable.

CONCLUSIONS

The susceptibility to hormone-triggered mood changes appears to depend upon women's general tendency to experience distress and destabilization of mood, as captured by personality trait Neuroticism. This could aid clinicians evaluate hormone-related vulnerability for mood disorders in women and may guide targeted prevention in reproductive care.

Preschool negative emotionality predicts activity and connectivity of the fusiform face area and amygdala in later childhood

Negative emotionality (NE) refers to individual differences in the propensity to experience and react with negative emotions and is associated with increased risk of psychological disorder. However, research on the neural bases of NE has focused almost exclusively on amygdala activity during emotional face processing. This study broadened this framework by examining the relationship between observed NE in early childhood and subsequent neural responses to emotional faces in both the amygdala and the fusiform face area (FFA) in a late childhood/early adolescent sample. Measures of NE were obtained from children at age 3 using laboratory observations, and functional magnetic resonance imaging (fMRI) data were collected when these children were between the ages of 9 and 12 while performing a visual stimulus identity matching task with houses and emotional faces as stimuli. Multiple regression analyses revealed that higher NE at age 3 is associated with significantly greater activation in the left amygdala and left FFA but lower functional connectivity between these two regions during the face conditions. These findings suggest that those with higher early NE have subsequent alterations in both activity and connectivity within an extended network during face processing.

Cognitive benefit and cost of acute stress is differentially modulated by individual brain state

Acute stress is associated with beneficial as well as detrimental effects on cognition in different individuals. However, it is not yet known how stress can have such opposing effects. Stroop-like tasks typically show this dissociation: stress diminishes speed, but improves accuracy. We investigated accuracy and speed during a stroop-like task of 120 healthy male subjects after an experimental stress induction or control condition in a randomized, counter-balanced cross-over design; we assessed brain–behavior associations and determined the influence of individual brain connectivity patterns on these associations, which may moderate the effect and help identify stress resilience factors. In the mean, stress was associated to increase in accuracy, but decrease in speed. Accuracy was associated to brain activation in a distributed set of brain regions overlapping with the executive control network (ECN) and speed to temporo-parietal activation. In line with a stress-related large-scale network reconfiguration, individuals showing an upregulation of the salience and down-regulation of the executive-control network under stress displayed increased speed, but decreased performance. In contrast, individuals who upregulate their ECN under stress show improved performance. Our results indicate that the individual large-scale brain network balance under acute stress moderates cognitive consequences of threat.

Tell me what to do: Stress facilitates stimulus-response learning by instruction

Learning by explicit instruction is a highly efficient way to instantaneously learn new behaviors and to overcome potentially harmful learning by trial-and-error. Despite the importance of instructed learning for education, influences on the efficacy of an instruction are currently unknown. Decades of research, however, showed that stress is a powerful modulator of learning and memory, including the acquisition of stimulus-response (S-R) associations. Moreover, brain areas critical for instructed learning are a major target of hormones and neurotransmitters released during stress. Thus, we investigated here whether acute stress affects instructed S-R learning and whether this effect differs for trial-and-error learning. To this end, healthy participants underwent a stressor (Socially Evaluated Cold Pressor Test) or a control manipulation before learning arbitrary S-R associations. For half of the stimuli, participants were explicitly instructed about the correct association, whereas the remaining associations had to be learned by trial-and-error. As expected, the instruction resulted in better performance and enhanced explicit rule knowledge compared to trial-and-error learning. Stress further boosted the beneficial effect of an explicit instruction on learning performance, while leaving trial-and-error learning unchanged. These beneficial effects of stress were directly correlated with the activity of the autonomic nervous system and the concentration of cortisol. Moreover, acute stress could override the detrimental effect of high trait anxiety levels on instructed S-R learning performance. Our findings indicate that acute stress may facilitate learning from instruction, which may represent a highly efficient way to learn how to act, without the necessity of own experience, that helps to save cognitive resources during a stressful encounter.

Physical neglect during childhood alters white matter connectivity in healthy young males

BACKGROUND

Childhood adversity (CA) leads to greater vulnerability for psychopathology by causing structural as well as functional brain abnormalities. Recent findings on gray matter effects point towards the importance of identifying CA outcome as a function of different CA types, varying in the dimensions of threat and deprivation. Using diffusion tensor imaging, we investigate whether different forms of CA impact differently on white matter connectivity in a healthy cohort not confounded by other aspects of disease.

METHODS

In 120 healthy young males, we assessed different forms of maltreatment during childhood with the Childhood Trauma Questionnaire (CTQ). Fractional anisotropy (FA) and mean diffusivity (MD) images were generated and projected onto a white matter skeleton using tract-based spatial statistics. Correlational analysis between FA, MD, and CTQ subscores was then performed using voxelwise statistics.

RESULTS

Of all CTQ-subscores, only physical neglect (PN) predicted a decrease of FA but not MD in the bilateral anterior thalamic radiation around the middle frontal gyrus and the right inferior fronto-occipital fasciculus, the inferior longitudinal fasciculus, the cingulum and precuneus. Reduced FA in the posterior cingulum was related to the effects of PN during childhood on anxiety levels at trend level.

CONCLUSIONS

PN may have severe consequences and should be considered equally important to more active forms of abuse. FA changes, particularly in the cingulum, actually appear to a functional consequence and are linked to trait anxiety, a personality dimension that is suggested to be a transdiagnostic risk factor of affective disorders. Potentially this reveals a mechanistic chain that forms one pathyway from CA to disease.

Association between Neuroticism and Emotional Face Processing

Neuroticism is one of the “Big Five” personality factors and is characterized by a tendency to experience negative affect. We aimed to investigate how neuroticism influences the neural correlates for processing of emotional facial expressions. 68 healthy participants were presented with emotional dynamic facial stimuli, i.e. happy, neutral or angry, during functional MRI. Brain activations for the contrasts emotional vs. neutral, happy vs. neutral and angry vs. neutral were correlated with individuals’ neuroticism scores as obtained by the NEO Five Factor Inventory questionnaire and additionally investigated for gender differences. The bilateral medial temporal gyrus (MTG) was identified as key region in the processing of emotional faces and activations within this region correlated with individual neuroticism scores. Although female participants showed significantly stronger activation differences between emotional and neutral facial expressions in the left MTG, the correlation between activation and neuroticism scores did not show any significant gender differences. Our results offer for the first time a biological correlate within the face processing network for enhanced reactivity of neurotic individuals to emotional facial expressions which occurs similarly for both male and female participants.

Emotion and sex of facial stimuli modulate conditional automaticity in behavioral and neuronal interference in healthy men

Our surrounding provides a host of sensory input, which we cannot fully process without streamlining and automatic processing. Levels of automaticity differ for different cognitive and affective processes. Situational and contextual interactions between cognitive and affective processes in turn influence the level of automaticity. Automaticity can be measured by interference in Stroop tasks. We applied an emotional version of the Stroop task to investigate how stress as a contextual factor influences the affective valence-dependent level of automaticity. 120 young, healthy men were investigated for behavioral and brain interference following a stress induction or control procedure in a counter-balanced cross-over-design. Although Stroop interference was always observed, sex and emotion of the face strongly modulated interference, which was larger for fearful and male faces. These effects suggest higher automaticity when processing happy and also female faces. Supporting behavioral patterns, brain data show lower interference related brain activity in executive control related regions in response to happy and female faces. In the absence of behavioral stress effects, congruent compared to incongruent trials (reverse interference) showed little to no deactivation under stress in response to happy female and fearful male trials. These congruency effects are potentially based on altered context- stress-related facial processing that interact with sex-emotion stereotypes. Results indicate that sex and facial emotion modulate Stroop interference in brain and behavior. These effects can be explained by altered response difficulty as a consequence of the contextual and stereotype related modulation of automaticity.

How the brain connects in response to acute stress: A review at the human brain systems level

The brain's response to stress is a matter of extensive neurocognitive research in an attempt to unravel the mechanistic underpinnings of neural adaptation. In line with the broadly defined concept of acute stress, a wide variety of induction procedures are used to mimic stress experimentally. We set out to review commonalities and diversities of the stress-related functional activity and connectivity changes of functional brain networks in healthy adults across procedures. The acute stress response is consistently associated with both increased activity and connectivity in the salience network (SN) and surprisingly also with increased activity in the default mode network (DMN), while most studies show no changes in the central executive network. These results confirm earlier findings of an essential, coordinating role of the SN in the acute stress response and indicate a dynamic role of the DMN whose function is less clear. Moreover, paradigm specific brain responses have to be taken into account when investigating the role and the within and between network connectivity of these three networks.

How Human Amygdala and Bed Nucleus of the Stria Terminalis May Drive Distinct Defensive Responses

The ability to adaptively regulate responses to the proximity of potential danger is critical to survival and imbalance in this system may contribute to psychopathology. The bed nucleus of the stria terminalis (BNST) is implicated in defensive responding during uncertain threat anticipation whereas the amygdala may drive responding upon more acute danger. This functional dissociation between the BNST and amygdala is however controversial, and human evidence scarce. Here we used data from two independent functional magnetic resonance imaging studies [n = 108 males and n = 70 (45 females)] to probe how coordination between the BNST and amygdala may regulate responses during shock anticipation and actual shock confrontation. In a subset of participants from Sample 2 (n = 48) we demonstrate that anticipation and confrontation evoke bradycardic and tachycardic responses, respectively. Further, we show that in each sample when going from shock anticipation to the moment of shock confrontation neural activity shifted from a region anatomically consistent with the BNST toward the amygdala. Comparisons of functional connectivity during threat processing showed overlapping yet also consistently divergent functional connectivity profiles for the BNST and amygdala. Finally, childhood maltreatment levels predicted amygdala, but not BNST, hyperactivity during shock anticipation. Our results support an evolutionary conserved, defensive distance-dependent dynamic balance between BNST and amygdala activity. Shifts in this balance may enable shifts in defensive reactions via the demonstrated differential functional connectivity. Our results indicate that early life stress may tip the neural balance toward acute threat responding and via that route predispose for affective disorder.SIGNIFICANCE STATEMENT Previously proposed differential contributions of the BNST and amygdala to fear and anxiety have been recently debated. Despite the significance of understanding their contributions to defensive reactions, there is a paucity of human studies that directly compared these regions on activity and connectivity during threat processing. We show strong evidence for a dissociable role of the BNST and amygdala in threat processing by demonstrating in two large participant samples that they show a distinct temporal signature of threat responding as well as a discriminable pattern of functional connections and differential sensitivity to early life threat.

Acute Stress Enhances Emotional Face Processing in the Aging Brain

BACKGROUND

Healthy aging has been associated with stable emotional well-being and attenuated brain responses to negative stimuli. At the same time, depressive symptoms are common in older adults. The neural mechanisms behind this paradox remain to be clarified. We hypothesized that acute stress could alter emotion processing in healthy aging brain and constitute a pathway to vulnerability.

METHODS

Using a randomized, controlled crossover design, we explored the influence of acute stress on brain responses to happy and fearful facial expressions in 25 older adults (60-75 years of age) and 25 young (18-30 years of age) control subjects. Groups were matched on trait anxiety and education. Subjects underwent two separate functional magnetic resonance imaging sessions involving acute stress or a control procedure.

RESULTS

Affective and physiological responses to the stressor were similar between the two age groups. On a whole-brain level, we revealed a significant age by stress interaction in the fusiform gyrus, indicating a selective enhancement of neural activity with stress in elderly subjects only. When specifically aiming analysis at the amygdala, we found the same stress-related increase in activity in elderly subjects only. Modulation of amygdala reactivity due to stress correlated with trait conscientiousness in elderly subjects exclusively.

CONCLUSIONS

Compared with younger adults, healthy older adults showed increased responsivity of brain regions involved in face and emotion processing while stressed. These findings suggest that increased reactivity of this neural circuitry after acute stress may constitute one mechanism by which emotional well-being during healthy aging could rapidly change into heightened vulnerability for affective disorders.

Academic stress and personality interact to increase the neural response to high-calorie food cues

Psychosocial stress is associated with an increased intake of palatable foods and weight gain in stress-reactive individuals. Personality traits have been shown to predict stress-reactivity. However, it is not known if personality traits influence brain activity in regions implicated in appetite control during psychosocial stress. The current study assessed whether Gray's Behavioural Inhibition System (BIS) scale, a measure of stress-reactivity, was related to the activity of brain regions implicated in appetite control during a stressful period. Twenty-two undergraduate students participated in a functional magnetic resonance imaging (fMRI) experiment once during a non-exam period and once during final exams in a counter-balanced order. In the scanner, they viewed food and scenery pictures. In the exam compared with the non-exam condition, BIS scores related to increased perceived stress and correlated with increased blood-oxygen-level dependent (BOLD) response to high-calorie food images in regions implicated in food reward and subjective value, such as the ventromedial prefrontal cortex, (vmPFC) and the amygdala. BIS scores negatively related to the functional connectivity between the vmPFC and the dorsolateral prefrontal cortex. The results demonstrate that the BIS trait influences stress reactivity. This is observed both as an increased activity in brain regions implicated in computing the value of food cues and decreased connectivity of these regions to prefrontal regions implicated in self-control. This suggests that the effects of real life stress on appetitive brain function and self-control is modulated by a personality trait. This may help to explain why stressful periods can lead to overeating in vulnerable individuals.

Peering into the brain to predict behavior: Peer-reported, but not self-reported, conscientiousness links threat-related amygdala activity to future problem drinking

Personality traits such as conscientiousness as self-reported by individuals can help predict a range of outcomes, from job performance to longevity. Asking others to rate the personality of their acquaintances often provides even better predictive power than using self-report. Here, we examine whether peer-reported personality can provide a better link between brain function, namely threat-related amygdala activity, and future health-related behavior, namely problem drinking, than self-reported personality. Using data from a sample of 377 young adult university students who were rated on five personality traits by peers, we find that higher threat-related amygdala activity to fearful facial expressions is associated with higher peer-reported, but not self-reported, conscientiousness. Moreover, higher peer-reported, but not self-reported, conscientiousness predicts lower future problem drinking more than one year later, an effect specific to men. Remarkably, relatively higher amygdala activity has an indirect effect on future drinking behavior in men, linked by peer-reported conscientiousness to lower future problem drinking. Our results provide initial evidence that the perceived conscientiousness of an individual by their peers uniquely reflects variability in a core neural mechanism supporting threat responsiveness. These novel patterns further suggest that incorporating peer-reported measures of personality into individual differences research can reveal novel predictive pathways of risk and protection for problem behaviors.

Intrinsic functional connectivity between amygdala and hippocampus during rest predicts enhanced memory under stress

Declarative memories of stressful events are less prone to forgetting than mundane events. Animal research has demonstrated that such stress effects on consolidation of hippocampal-dependent memories require the amygdala. In humans, it has been shown that during learning, increased amygdala-hippocampal interactions are related to more efficient memory encoding. Animal models predict that following learning, amygdala-hippocampal interactions are instrumental to strengthening the consolidation of such declarative memories. Whether this is the case in humans is unknown and remains to be empirically verified. To test this, we analyzed data from a sample of 120 healthy male participants who performed an incidental encoding task and subsequently underwent resting-state functional MRI in a stressful and a neutral context. Stress was assessed by measures of salivary cortisol, blood pressure, heart rate, and subjective ratings. Memory was tested afterwards outside of the scanner. Our data show that memory was stronger in the stress context compared to the neutral context and that stress-induced cortisol responses were associated with this memory enhancement. Interestingly, amygdala-hippocampal connectivity during post-encoding awake rest regardless of context (stress or neutral) was associated with the enhanced memory performance under stress. Thus, our findings are in line with a role for intrinsic functional connectivity during rest between the amygdala and the hippocampus in the state effects of stress on strengthening memory.

The role of white matter in personality traits and affective processing in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is characterized by affective processing bias and variations in personality traits. It is still unknown whether these features are linked to the same structural brain alterations. The aim of this study was to investigate relationships between specific personality traits, white matter (WM) properties, and affective processing in BD and HC.

METHODS

24 healthy controls (HC) and 38 adults with BDI (HC: 29.47 ± 2.23 years, 15 females; BDI: 32.44 ± 1.84 years, 20 females) completed clinical scales and the Big Five Inventory. They were also administered the Affective Go/No-Go (AGN) and the Rapid Visual Processing (RVP) tasks of the Cambridge Neuropsychological Test Automated Battery. Diffusion Tensor Imaging (DTI) assessed the microstructure of WM tracts.

RESULTS

In BDI measures of WM properties were reduced across all major brain white matter tracts. As expected, individuals with BDI reported greater neuroticism, lower agreeableness and conscientiousness, and made a greater number of errors in response to affective stimuli in the AGN task compared to HC. High neuroticism scores were associated with faster AGN latency, and overall reduced AGN accuracy in both HC and BDI. Elevated FA values were associated with reduced neuroticism and increased cognitive processing in HC but not in BDI.

CONCLUSIONS

Our findings showed important potential links between personality, affective processing and WM integrity in BD. In the future therapeutic interventions for BD using brain stimulation protocols might benefit from the use of DTI to target pathways underlying abnormal affective processing.

Thinking too much: self-generated thought as the engine of neuroticism

Neuroticism is a dimension of personality that captures trait individual differences in the tendency to experience negative thoughts and feelings. Established theories explain neuroticism in terms of threat sensitivity, but have limited heuristic value since they cannot account for features of neuroticism that are unrelated to threat, such as creativity and negative psychological states experienced in benign, threat-free environments. We address this issue by proposing that neuroticism stems from trait individual differences in activity in brain circuits that govern the nature of self-generated thought (SGT). We argue our theory explains not only the association of neuroticism with threat sensitivity but also the prominence within the neurotic mind of representations of information that are unrelated to the way the world is right now, such as creativity and nonsituational 'angst'.

Altered short-term plasticity within the working memory neural network: Is it neuroticism or is it depression?

In the present article, we discuss (1) the importance of assessing and statistically considering both clinical and subclinical forms of depression when examining the relationship between neuroticism and short-term plasticity within the working memory neural network, and (2) the hypothesis of an antagonism between neuroticism and conscientiousness in personality research. We suggest that (1) neuroticism and depression should be examined in a relational manner, and (2) neuroticism and conscientiousness should not be antagonized.

Author's response to commentary 'Depressive symptomatology should be systematically controlled for in neuroticism research'

In the commentary by Bianchi and Laurent (2015), the authors suggest that depressive symptoms should be controlled for when examining the neurobiology associated with trait neuroticism. We fully agree that the relation between neuroticism and symptoms of stress-related psychiatric disorders, such as major depressive disorder and anxiety disorders, should not be overlooked when studying its neural correlates. However, instead of treating this relation as a potential confound, we consider it to be of particular importance to include depressive symptoms when studying the influence of acute psychological stress on neural mechanisms related to trait neuroticism. Regardless of this principal disagreement, we also confirmed empirically that depression scores did not affect our voxel-wise results. In sum, our results were not confounded by depression scores and more importantly, our study question and design do not warrant including depression scores in our analysis.

The neurobiology of dispositional negativity and attentional biases to threat: Implications for understanding anxiety disorders in adults and youth

When extreme, anxiety can become debilitating. Anxiety disorders, which often first emerge early in development, are common and challenging to treat, yet the neurocognitive mechanisms that confer increased risk have only recently begun to come into focus. Here we review recent work highlighting the importance of neural circuits centered on the amygdala. We begin by describing dispositional negativity, a core dimension of childhood temperament and adult personality and an important risk factor for the development of anxiety disorders and other kinds of stress-sensitive psychopathology. Converging lines of epidemiological, neurophysiological, and mechanistic evidence indicate that the amygdala supports stable individual differences in dispositional negativity across the lifespan and contributes to the etiology of anxiety disorders in adults and youth. Hyper-vigilance and attentional biases to threat are prominent features of the anxious phenotype and there is growing evidence that they contribute to the development of psychopathology. Anatomical studies show that the amygdala is a hub, poised to govern attention to threat via projections to sensory cortex and ascending neuromodulatory systems. Imaging and lesion studies demonstrate that the amygdala plays a key role in selecting and prioritizing the processing of threat-related cues. Collectively, these observations provide a neurobiologically-grounded framework for understanding the development and maintenance of anxiety disorders in adults and youth and set the stage for developing improved intervention strategies.