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The hippocampus is a central modulator of the HPA-axis, impacting the regulation of stress on brain structure, function, and behavior. The current study assessed whether three different types of 3 months mental Training Modules geared towards nurturing (a) attention-based mindfulness, (b) socio-affective, or (c) socio-cognitive skills may impact hippocampal organization by reducing stress. We evaluated mental training-induced changes in hippocampal subfield volume and intrinsic functional connectivity, by combining longitudinal structural and resting-state fMRI connectivity analysis in 332 healthy adults. We related these changes to changes in diurnal and chronic cortisol levels. We observed increases in bilateral cornu ammonis volume (CA1-3) following the 3 months compassion-based module targeting socio-affective skills (Affect module), as compared to socio-cognitive skills (Perspective module) or a waitlist cohort with no training intervention. Structural changes were paralleled by relative increases in functional connectivity of CA1-3 when fostering socio-affective as compared to socio-cognitive skills. Furthermore, training-induced changes in CA1-3 structure and function consistently correlated with reductions in cortisol output. Notably, using a multivariate approach, we found that other subfields that did not show group-level changes also contributed to changes in cortisol levels. Overall, we provide a link between a socio-emotional behavioural intervention, changes in hippocampal subfield structure and function, and reductions in cortisol in healthy adults.
Too much stress is harmful to the brain and overall health, as it can lead to chronically high levels of the stress hormone cortisol. The part of the brain that regulates memory and emotions, called the hippocampus, is especially sensitive to stress because it has a high number of receptors that bind to cortisol. This connection may explain why stress can lead to memory lapses or strong emotions. Studies have shown that mental training exercises, such as mindfulness and meditation, may change the structure of the brain and reduce stress. However, the results from these experiments have been mixed due to the variation in mental practices used by different programs. Here, Valk, Engert et al. set out to find how distinct types of mental training affect the brain, focusing on the hippocampus and cortisol levels. The team used various magnetic resonance imaging techniques to study the hippocampus of 322 healthy adult volunteers who had undergone three months of mental training. The relationship between mental training, hippocampus size, and stress levels was complex when studying the results of each individual. However, when the results were grouped together, it revealed that volunteers who underwent training to increase empathy and compassion experienced expansion in parts of their hippocampus. As these areas of the brain increased in size, these individuals experienced corresponding reductions in cortisol levels. But volunteers who underwent mental training focused on attention or developing perspective did not experience such increases. These findings suggest that mental training to increase empathy and compassion alters brain structure and lowers cortisol levels. Future studies may explain how this happens, which could lead to improved mental training programs for mitigating stress.
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Hipocampo , Hidrocortisona , Imagen por Resonancia Magnética , Humanos , Hidrocortisona/metabolismo , Masculino , Femenino , Hipocampo/fisiología , Adulto , Adulto Joven , Atención Plena , Ritmo Circadiano/fisiología , Estrés PsicológicoRESUMEN
Mindfulness-based interventions have become a popular means to reduce stress. However, the specific mechanisms driving observed stress reduction remain understudied. The Monitor and Acceptance Theory suggests that the cultivation of monitoring and acceptance skills are necessary moderators of practice-induced stress reduction. In the context of the ReSource Project, a large healthy adult sample underwent three 3-month mental training modules targeting either attentional (Presence module), socio-affective (Affect module) or socio-cognitive skills (Perspective module). In the current study, the development of a range of inter-individual differences in mindfulness-, interoception- and compassion-related traits - which mapped to either monitoring or acceptance categories - was tracked. The relationship of these training-induced changes with cortisol stress reactivity after the three distinct 3-month training modules was explored. We found that stress sensitivity was particularly modulated by a differential adaptivity of one cultivated attentional capacity - Attention regulation - which predicted higher cortisol reactivity after mere attention training (Presence) but was associated with lower stress-induced cortisol release after additional socio-affective and socio-cognitive practice (Affect and Perspective). However, this effect did not survive multiple comparisons correction, and analyses were limited by the sample size available. We conclude that our study provides preliminary support of the Monitor and Acceptance Theory, lending weight to the advantage of primary attentional increases in order to fully harness the beneficial effects of socio-affective training, ultimately leading to stress reduction. Although training-induced increases in acceptance were not directly shown to contribute to lowering cortisol stress reactivity, the data suggest an additional benefit of socio-affective and socio-cognitive training that is not directly captured within the current analyses. Our study corroborates the importance of going beyond the training of attention monitoring to foster stress resilience, and highlights that mental training relies on the co-development of several interacting processes to successfully attenuate stress. Further exploring the overarching concept of acceptance in future research may prove beneficial to the theoretical framework of MAT, and in understanding the processes by which stress reduction occurs.
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Atención , Hidrocortisona , Atención Plena , Estrés Psicológico , Humanos , Hidrocortisona/metabolismo , Masculino , Estrés Psicológico/metabolismo , Femenino , Atención/fisiología , Adulto , Adulto Joven , Saliva/metabolismo , Saliva/química , Empatía/fisiología , Interocepción/fisiologíaRESUMEN
Stress and stress-associated disease are considered the health epidemic of the 21st century. Interestingly, despite experiencing similar amounts of stress than those falling ill, some individuals are protected against the "wear and tear of daily life". Based on the notion that mindfulness training strengthens stress resilience, we explored whether facets of trait mindfulness, prior to training intervention, are linked to acute psychosocial stress reactivity and chronic stress load. To assess different mindfulness facets, over 130 participants completed the Five Facet Mindfulness Questionnaire (FFMQ) and the Freiburg Mindfulness Inventory (FMI). For acute stress induction, a standardized psychosocial stress test was conducted. Subjective stress, sympathetic and parasympathetic activity, and levels of the hypothalamic-pituitary-adrenal axis end hormone cortisol were assessed repeatedly. Additionally, levels of hair cortisol and cortisone as indices of the long-term physiological stress load were collected. We found differential associations of different facets of mindfulness with subjective stress, cortisol, and hair cortisone levels. Specifically, the trait mindfulness facets FMI "Acceptance" and the ability to put one's inner experience into words (FFMQ "Describing") were associated with lower acute subjective and cortisol stress reactivity. Contrarily, monitoring-related trait mindfulness facets (FFMQ "Acting with Awareness" and "Observing") were associated with higher acute cortisol and marginally higher long-term cortisone release. Our results suggest granularity of the mindfulness construct. In accordance with the "Monitor and Acceptance Theory", especially acceptance-related traits buffered against stress, while monitoring-related traits seemed to be maladaptive in the context of stress. The current results give valuable guidance for the conceptualization of mindfulness-based interventions geared towards stress reduction.
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Cabello , Hidrocortisona , Sistema Hipotálamo-Hipofisario , Atención Plena , Estrés Psicológico , Humanos , Atención Plena/métodos , Masculino , Hidrocortisona/metabolismo , Hidrocortisona/análisis , Estrés Psicológico/metabolismo , Estrés Psicológico/psicología , Femenino , Adulto , Cabello/química , Encuestas y Cuestionarios , Sistema Hipotálamo-Hipofisario/metabolismo , Adulto Joven , Sistema Hipófiso-Suprarrenal/metabolismo , Enfermedad Crónica , Cortisona/metabolismo , Persona de Mediana EdadRESUMEN
BACKGROUND: Childhood maltreatment is associated with pervasive risk for depression. However, the immediate cognitive and neural mechanisms that mediate this risk during development are unknown. We here studied the impact of maltreatment on self-generated thought (SGT) patterns and their association with depressive symptoms, subcallosal cingulate cortex (SCC) thickness, and cortisol levels in children. METHODS: We recruited 183 children aged 6-12 years, 96 of which were exposed to maltreatment. Children performed a mind wandering task to elicit SGTs. A subgroup of children underwent structural magnetic resonance imaging (N = 155) for SCC thickness analyses and saliva collection for quantification of free cortisol concentrations (N = 126) was collected. Using network analysis, we assessed thought networks and compared these networks between children with and without maltreatment exposure. Using multilevel analyses, we then tested the association between thought networks of children with maltreatment exposure with depressive symptoms, SCC thickness, and cortisol levels. RESULTS: Children exposed to maltreatment generated fewer positively valenced thoughts. Network analysis revealed rumination-like thought patterns in children with maltreatment exposure, which were associated with depressive symptoms, SCC thickness, and cortisol levels. Children with maltreatment exposure further exhibited decreased future-self thought coupling, which was associated with depressive symptoms, while other-related and past-oriented thoughts had the greatest importance within the network. CONCLUSIONS: Using a novel network analytic approach, we provide evidence that children exposed to maltreatment exhibit ruminative clustering of thoughts, which is associated with depressive symptoms and neurobiological correlates of depression. Our results provide a specific target for clinical translation to design early interventions for middle childhood. Targeting thought patterns in children with maltreatment exposure may be an effective strategy to effectively mitigate depression risk early in life.
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Maltrato a los Niños , Depresión , Humanos , Niño , Depresión/psicología , Hidrocortisona , Giro del Cíngulo/diagnóstico por imagen , Maltrato a los Niños/psicologíaRESUMEN
Exposure to excessive and long-term stress may result in dysregulation of the stress system, including the acute stress response. In particular, failure to downregulate stress-related reactivity may lead to prolonged stress responses and the accumulation of allostatic load. However, the contribution of altered acute cortisol recovery to chronic stress and associated health impairments has often been neglected. Addressing this lack of research, we explored whether recovery from - more so than reactivity to - acute stress captures the basal stress load of an individual. Using Piecewise Growth Curve Models with Landmark Registration, we analyzed cortisol reactivity and recovery slopes of 130 healthy participants exposed to a standardized psychosocial laboratory stressor. Reactivity and recovery were predicted by measures indicative of long-term stress and its downstream effects, including self-report questionnaires, diurnal cortisol indices [cortisol awakening response (CAR); diurnal cortisol slope], markers of pro-inflammatory activity (interleukin-6; high-sensitive C-reactive protein), and hippocampal volume (HCV). Among these measures, only an increased CAR was specifically and consistently associated with relatively impaired recovery. Since the CAR represents the physiological enhancement needed to meet the anticipated demands of the forthcoming day, this finding may highlight the contribution of cognitive processes in determining both CAR and acute stress recovery. Furthermore, greater cortisol reactivity covaried with smaller HCV, showing that increased acute reactivity translates to health-relevant downstream effects. The lack of further associations between long-term and acute stress measures may arise from biases in self-reported chronic stress and the rigorously health-screened study sample. Overall, our findings suggest that while cortisol stress recovery might not supersede reactivity as an indicator of the long-term stress load or associated health effects, recovery and reactivity have differential utility in describing individuals' allostatic states.
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This perspective article was written by invitation of the editors in chief as a summary and extension of the symposium entitled Psychoneuroendocrine Research in the Era of the Replication Crisis which was held at the virtual meeting of the International Society of Psychoneuroendocrinology 2021. It highlights the opportunities presented by the application of open and reproducible scientific practices in psychoneuroendocrinology (PNE), an interdisciplinary field at the intersection of psychology, endocrinology, immunology, neurology, and psychiatry. It conveys an introduction to the topics preregistration, registered reports, quantifying the impact of equally-well justifiable analysis decisions, and open data and scripts, while emphasizing 'selfish' reasons to adopt such practices as individual researcher. Complementary to the call for adoption of open science practices, we highlight the need for methodological best practice guidelines in the field of PNE, which could further contribute to enhancing replicability of results. We propose concrete steps for future actions and provide links to additional resources for those interested in adopting open and reproducible science practices in future studies.
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OBJECTIVE: This study aimed to investigate the effect of regular contemplative mental training on endocrine and psychological indices of long-term stress. METHODS: An open-label efficacy trial that comprised three distinct 3-month long modules targeting attention and interoception, socioaffective, or sociocognitive abilities through dyadic exercises and secularized meditation practices was conducted with healthy adults. Participants underwent the training for 3 or 9 months, or were assigned to a retest control cohort. Chronic stress indices were assayed at four time points: pretraining and after 3, 6, and 9 months. The main outcome measures were cortisol (HC) and cortisone (HE) concentration in hair and self-reported long-term stress. RESULTS: Of 362 initially randomized individuals, 30 dropped out before study initiation (n = 332; mean [SD] age = 40.7 [9.2] years; 197 women). Hair-based glucocorticoid assays were available from n = 227, and questionnaire data from n = 326. Results from three separate training cohorts (TC1-3) revealed consistent decreases in HC and HE levels over the first three (TC3) to 6 months (TC1 and TC2) of training, with no further reduction at the final 9-month mark (baseline to end of training differences, HC, TC1: t(355) = 2.59, p = .010, contrast estimate (est.) [SE] = 0.35 [0.14]; HC, TC2: t(363) = 4.06, p < .001, est. = 0.48 [0.12]; HC, TC3: t(368) = 3.18, p = .002, est. = 0.41 [0.13]; HE, TC1: t(435) = 3.23, p = .001, est. = 0.45 [0.14]; HE, TC2: t(442) = 2.60, p = .010, est. = 0.33 [0.13]; HE, TC3: t(446) = 4.18, p < .001, est. = 0.57 [0.14]). Training effects on HC increased with individual compliance (practice frequency), and effects on both HC and HE were independent of training content and unrelated to change in self-reported chronic stress. Self-reported stress, and cortisol-to-dehydroepiandrosterone ratios as an exploratory endpoint, were also reduced, albeit less consistently. CONCLUSIONS: Our results point to the reduction of long-term cortisol exposure as a mechanism through which meditation-based mental training may exert positive effects on practitioners' health.Trial Registration: ClinicalTrials.gov identifier: NCT01833104.
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Interocepción , Meditación , Adulto , Cognición , Femenino , Glucocorticoides , Humanos , HidrocortisonaRESUMEN
Experience and thoughts that are unrelated to the external surroundings are pervasive features of human cognition. Research under the rubric of mind-wandering suggests that such internal experience is context-dependent, and that the content of ongoing thought differentially influences a range of associated outcomes. However, evidence on how the extent of mind-wandering and its content translate from the laboratory to daily life settings is scarce. Furthermore, the relationship between such patterns of thought with markers of stress in daily life remains underexplored. In the current study, we examined multiple aspects of mind-wandering of ninety-three healthy participants (47 women, 25.4 ± 3.9 years) in both the laboratory and daily life and explored two questions: (a) how are mind-wandering extent and content correlated across both settings, and (b) what are their relationships with subjective stress and salivary cortisol levels in daily life? Our results suggest that the extent of off-task thinking is not correlated across contexts, while features of content-i.e., social, future-directed and negative thought content-robustly translate. We also found that daily life subjective stress was linked to more on-task, negative, and future-directed thinking, suggesting stress was linked with the need to act on personally relevant goals. Based on these results we speculate that differences in the links between stress and ongoing thought in daily life may be one reason why patterns of thinking vary from lab to everyday life. More generally, these findings underline the need to consider both context and content in investigating mind-wandering and associated features of subjective experience, and call for caution in generalizing laboratory findings to participants' daily lives.
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Atención/fisiología , Desempeño Psicomotor/fisiología , Estrés Psicológico/psicología , Análisis y Desempeño de Tareas , Adolescente , Adulto , Cognición/fisiología , Función Ejecutiva/fisiología , Femenino , Humanos , Masculino , Pensamiento/fisiología , Adulto JovenRESUMEN
Psychosocial stress is a ubiquitous phenomenon in our society. While acute stress responses are necessary and adaptive, excessive activation of neurobiological stress systems can predispose an individual to far-reaching adverse health outcomes. Living in a complex social environment, experiencing stress is not limited to challenges humans face individually. Possibly linked with our capacity for empathy, we also display the tendency to physiologically resonate with others' stress responses. This recently identified source of stress raises many interesting questions. In comparison to the wealth of studies that have advanced our understanding of sharing others' affective states, the physiological resonance of stress has only recently begun to be more closely investigated. The aim of the current paper is to review the existing literature surrounding the emerging area of "stress contagion", "empathic stress" or "stress resonance", as it has been variably called. After a brief introduction of the concepts of stress and empathy, we discuss several key studies that paved the way for the merging of empathy with the concept of physiological resonance. We then delineate recent empirical studies specifically focusing on the physiological resonance of stress. In the final section of this review, we highlight differences between these studies and discuss the variability in terminology used for what seems to be the same phenomenon. Lastly, potential health implications of chronic empathic stress are presented and possible mechanisms of physiological stress transmission are discussed.
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Empatía/fisiología , Hidrocortisona/metabolismo , Sistema Hipotálamo-Hipofisario , Percepción Social , Estrés Psicológico , Sistema Nervioso Simpático , Humanos , Sistema Hipotálamo-Hipofisario/metabolismo , Sistema Hipotálamo-Hipofisario/fisiopatología , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología , Sistema Nervioso Simpático/metabolismo , Sistema Nervioso Simpático/fisiopatologíaRESUMEN
The prevalence of psychosocial stress in Western societies is constantly on the rise. Its influence on social decision-making, however, remains poorly understood. Whereas, it is known that stress triggers psychological and physiological defense mechanisms, indications of such patterns in social decisions are ambivalent. We sought to elucidate the underlying mechanisms of stress-induced social decisions. We recruited 145 men, who were individually exposed to either a psychosocial stressor or a control condition, while primed with affiliation by interacting either with members of an in- or an out-group. We found that stressed participants were less trusting and engaged in less costly punishment compared to the non-stressed control group. Interacting with out-group members led to less reciprocity and more spiteful punishment. There was no interaction between stress and the affiliation conditions in any of the used social-decision-making paradigms. Lastly, while stress-reactive cortisol levels had no effect on trust behavior, higher baseline cortisol was correlated with greater trust. Our findings suggest that previous ambiguities in data reported on the influence of stress on social decisions, namely tend-and-befriend behavior may have arisen through critical social confounds in the induction of stress. When controlling for potential social confounds, stress may trigger fight-or-flight behavior as indicated by increased social anxiety. These findings highlight the considerable context-dependence of psychosocial stress and its effects on social behavior.