Cognitive Adaptation under Stress: A Case for the Mineralocorticoid Receptor

A second act for spironolactone: cognitive benefits in renal dysfunction - a critical review

Renal dysfunction or Chronic kidney disease (CKD) are increasingly associated with cognitive deficit and memory impairment, suggesting a crucial kidney-brain axis. This review examines spironolactone's emerging role as a neuroprotective agent in the context of renal dysfunction-induced cognitive impairment. As a selective mineralocorticoid receptor (MR) antagonist, spironolactone demonstrates multifaceted protective mechanisms beyond its well established renoprotective effects. Evidences also suggests that spironolactone attenuates neuroinflammation, mitigates oxidative stress in brain, preserve blood-brain barrier (BBB) integrity and regulates hormonal imbalances associated with renal dysfunction. This review focuses on the reported beneficial effects of spironolactone in various neurodegenerative diseases (NDDs). These mechanisms collectively protect against the neurodegeneration in memory impairment induced by renal dysfunction. The dual action of spironolactone on both renal and cerebral tissues presents a novel therapeutic advantage in addressing this complex pathophysiology. This study elucidates multiple beneficial mechanisms by which spironolactone addresses cognitive impairment associated with renal dysfunction. Spironolactone enhances BBB protection and restores BBB integrity which is often compromised with renal dysfunction. It promotes neuroplasticity (allowing for improved neural adaptation and cognitive function), additionally mediates cerebral blood flow (CBF) ensuring adequate oxygen and nutrient delivery to brain. Spironolactone's anti-inflammatory effects by inhibiting the nuclear factor-kappa B (NF-κB) pathway and modulation of neuregulin1 (NRG1)/v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4 (ERBB4) signaling effectively reduce neuroinflammation that contributes to memory impairment. It also mitigates oxidative stress by targeting NADPH-oxidase (NOX), a major source of reactive oxygen species (ROS) in the central nervous system (CNS). Spironolactone also maintains hormonal balance, particularly regarding aldosterone levels, which become dysregulated in renal dysfunction and negatively impact brain function. These insights provide new possibilities for developing targeted therapies against renal dysfunction-induced memory impairment.

Association of temporal self-regulation theory and its constructs with eating behavior: A systematic review and meta-analysis

Temporal Self-Regulation theory (TST) aims to address the intention-behavior gap; however, its applicability to eating behavior remains insufficiently validated. The objective of this review was to assess whether the constructs of TST are associated with eating behavior. A comprehensive literature review was conducted in December 2024, utilizing the databases Web of Science, PsycINFO, CINAHL, and EMBASE. A total of 21 articles, encompassing 7913 participants, were identified. Meta-analyses were performed to examine the associations between the theoretical constructs and eating behaviors. The findings indicated that intention (ES(z) = 0.50, 95% CI: 0.33, 0.68, P < 0.001; pooled r = 0.46), behavioral prepotency (ES(z) = 0.68, 95% CI: 0.31, 1.05, P < 0.001; pooled r = 0.59), and self-regulation capacity (ES(z) = 0.37, 95% CI: 0.25, 0.49, P < 0.001; pooled r = 0.35) are significantly associated with healthy eating behaviors. For unhealthy eating behaviors, significant associations were demonstrated only with intention (ES(z) = 0.47, 95% CI: 0.01, 0.93, P = 0.04; pooled r = 0.44) and behavioral prepotency (ES(z) = 0.39, 95% CI: 0.25, 0.53, P < 0.001; pooled r = 0.37). These findings suggest that TST is applicable to eating behaviors. In particular, future interventions should be grounded in scientific theory, with a focus on optimizing intention, behavioral prepotency, and self-regulation capacity, while also considering the cultural context and individual needs of the target population. These efforts are essential for achieving global dietary health goals and will contribute significantly to preventing the occurrence of diet-related noncommunicable diseases.

Memory Under Stress: From Adaptation to Disorder

Stressful events are ubiquitous in everyday life. Exposure to these stressors initiates the temporally orchestrated release of a multitude of hormones, peptides, and neurotransmitters that target brain areas that have been critically implicated in learning and memory. This review summarizes recent insights on the profound impact of stress on 4 fundamental processes of memory: memory formation, memory contextualization, memory retrieval, and memory flexibility. Stress mediators instigate dynamic alterations in these processes, thereby facilitating efficient responding under stress and the creation of a decontextualized memory representation that can effectively aid coping with novel future threats. While they are generally adaptive, the same stress-related changes may contribute to the rigid behaviors, uncontrollable intrusions, and generalized fear responding seen in anxiety disorders and posttraumatic stress disorder. Drawing on recent discoveries in cognitive neuroscience and psychiatry, this review discusses how stress-induced alterations in memory processes can simultaneously foster adaptation to stressors and fuel psychopathology. The transition from adaptive to maladaptive changes in the impact of stress on memory hinges on the nuanced interplay of stressor characteristics and individual predispositions. Thus, taking individual differences in the cognitive response to stressors into account is essential for any successful treatment of stress-related mental disorders.

Stress enhances memory for previously encoded events depending on stressor recall

Stressful events are typically well remembered, but their effects on memory for surrounding neutral events and the underlying mechanisms remain less clear. We hypothesized that stress would enhance memory for events surrounding the stressor, contingent on the memory of the stressor itself. Additionally, we predicted that memory for neutral events would be modulated by pairing them with stressor-related cues. To test these hypotheses, 122 healthy participants encoded a series of images before and after experiencing a stressful or control episode. During encoding, images were preceded by cues from stressor or control contexts. Memory for the stress or control episode and the encoded images was tested 24 h later. Our results showed enhanced memory prioritization, reflected in better memory for central versus peripheral features, for the stressful compared to the control episode. Exposure to the stressful episode further enhanced memory for neutral images preceding the stressor. However, this memory boost occurred only in participants with enhanced memory prioritization for the stressor. Memory for stimuli encoded after the stressor remained unaffected, and there was no evidence for the proposed cueing mechanism. These findings indicate that stressful events enhance memory consolidation only when these events themselves are distinctly represented in memory.

Acute stress and blockade of mineralocorticoid or glucocorticoid receptors: Effects on working memory

Although early studies were able to demonstrate a negative impact of stress on working memory performance, present research findings are heterogeneous. Numerous further studies found no effects or even improved performance, with the direction of these stress effects likely depending on the underlying biological mechanisms. The aim of this study was to investigate receptor-specific effects, as part of the stress-induced cortisol response, on working memory performance. Healthy, male participants (N=318, mean age 25.4 ± 5.1y) were exposed to the Trier Social Stress Test (TSST), a social-evaluative stress manipulation, or a non-stress control condition after they had received either spironolactone (blockade of the mineralocorticoid receptor, MR) or mifepristone (blockade of the glucocorticoid receptor, GR) or a placebo. Both substances are potent antagonists with high affinity for the respective receptors. To assess working memory, we implemented the n-back task subsequent to stress exposure, number of correct responses and reaction times served as outcome measures. We did not find effects of stress on working memory for any outcome measure, i.e. correct responses and reaction times. Yet, post hoc tests revealed that the group that received mifepristone exhibited longer reaction times under medium load conditions when compared to the placebo group, which might be an indication of the GR's involvement in task performance. We conclude that working memory performance is not affected by acute stress, at least under these prevalent conditions.

Effects of chronic stress on cognitive function - From neurobiology to intervention

Exposure to chronic stress contributes considerably to the development of cognitive impairments in psychiatric disorders such as depression, generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and addictive behavior. Unfortunately, unlike mood-related symptoms, cognitive impairments are not effectively treated by available therapies, a situation in part resulting from a still incomplete knowledge of the neurobiological substrates that underly cognitive domains and the difficulty in generating interventions that are both efficacious and safe. In this review, we will present an overview of the cognitive domains affected by stress with a specific focus on cognitive flexibility, behavioral inhibition, and working memory. We will then consider the effects of stress on neuronal correlates of cognitive function and the factors which may modulate the interaction of stress and cognition. Finally, we will discuss intervention strategies for treatment of stress-related disorders and gaps in knowledge with emerging new treatments under development. Understanding how cognitive impairment occurs during exposure to chronic stress is crucial to make progress towards the development of new and effective therapeutic approaches.

ClassIIb histone deacetylase participates in perioperative neurocognitive disorders in elderly mice via HSP90/GR signaling pathway

OBJECTIVE

Multiple factors contribute to the development of perioperative neurocognitive disorders (PND). This study was designed to investigate whether Histone Deacetylase 6 (HDAC6) was involved in the formation of postoperative cognitive dysfunction in elderly mice by regulating the degree of acetylation of heat shock protein (HSP90) and related protein functions and quantities.

METHODS

C57BL/6 J male mice were randomly divided into six groups: control naive (group Control), anesthesia (group Anesthesia), splenectomy surgery (group Surgery), splenectomy surgery plus dissolvent (group Vehicles), splenectomy surgery plus the inhibitor ACY-1215 (group Ricolinostat), and splenectomy surgery plus the inhibitor RU-486(group Mifepristone). After the mice were trained for Morris Water Maze (MWM) test for five days, anesthesia and operational surgery were carried out the following day. Cognitive function was assessed on the 1st, 3rd and 7th days post-surgery. The hippocampi were harvested on days 1, 3, and 7 post-surgeries for Western blots and ELISA assays.

RESULTS

Mice with the splenectomy surgery displayed the activation of the hypothalamic-pituitary-adrenal axis (HPA-axis), marked an increase in adrenocorticotropic hormone (ACTH), glucocorticoid, mineralocorticoid at the molecular level and impaired spatial memory in the MWM test. The hippocampus of surgical groups showed a decrease in acetylated HSP90, a rise in glucocorticoid receptor (GR)-HSP90 association, and an increase in GR phosphorylation and translocation. HDAC6 was increased after the surgical treated. Using two specific inhibitors, HDAC6 inhibitor Ricolinostat (ACY-1215) and GR inhibitor Mifepristone (RU-486), can partially mitigate the effects caused by surgical operation.

CONCLUSIONS

Abdominal surgery may impair hippocampal spatial memory, possibly through the HDAC6-triggered increase in the function of HSP90, consequently strengthening the negative role of steroids in cognitive function. Targeting HDAC6- HSP90/GR signaling may provide a potential avenue for the treatment of the impairment of cognitive function after surgery.

The emerging role of rapid corticosteroid actions on excitatory and inhibitory synaptic signaling in the brain

Over the past two decades, there has been increasing evidence for the importance of rapid-onset actions of corticosteroid hormones in the brain. Here, we highlight the distinct rapid corticosteroid actions that regulate excitatory and inhibitory synaptic transmission in the hypothalamus, the hippocampus, basolateral amygdala, and prefrontal cortex. The receptors that mediate rapid corticosteroid actions are located at or close to the plasma membrane, though many of the receptor characteristics remain unresolved. Rapid-onset corticosteroid effects play a role in fast neuroendocrine feedback as well as in higher brain functions, including increased aggression and anxiety, and impaired memory retrieval. The rapid non-genomic corticosteroid actions precede and complement slow-onset, long-lasting transcriptional actions of the steroids. Both rapid and slow corticosteroid actions appear to be indispensable to adapt to a continuously changing environment, and their imbalance can increase an individual's susceptibility to psychopathology.

Decision-making under stress: A psychological and neurobiological integrative model

Understanding the impact of stress on cognitive processes, particularly decision-making, is crucial as it underpins behaviors essential for survival. However, research in this domain has yielded disparate results, with inconsistencies evident across stress-induction paradigms and drug administration protocols designed to investigate specific stress pathways or neuromodulators. Building upon empirical studies, this research identifies a multifaceted matrix of variables contributing to the divergent findings. This matrix encompasses factors such as the temporal proximity between stressors and decision tasks, the nature of stressors and decision contexts, individual characteristics including psychobiological profiles and affective states at the time of decision-making and even cultural influences. In response to these complexities, we propose a comprehensive model that integrates these relevant factors and their intricate interplay to elucidate the mechanisms governing decision-making during stressful events. By synthesizing these insights, our model not only refines existing paradigms but also provides a framework for future study designs, offering avenues for theoretical advancements and translational developments in the field of stress's impact on cognitive functions. This research contributes to a deeper understanding of the nuanced relationship between stress and decision-making, ultimately advancing our knowledge of cognitive processes under challenging conditions.

Acute Stress Effects on Statistical Learning and Episodic Memory

Stress is widely considered to negatively impact hippocampal function, thus impairing episodic memory. However, the hippocampus is not merely the seat of episodic memory. Rather, it also (via distinct circuitry) supports statistical learning. On the basis of rodent work suggesting that stress may impair the hippocampal pathway involved in episodic memory while sparing or enhancing the pathway involved in statistical learning, we developed a behavioral experiment to investigate the effects of acute stress on both episodic memory and statistical learning in humans. Participants were randomly assigned to one of three conditions: stress (socially evaluated cold pressor) immediately before learning, stress ∼15 min before learning, or no stress. In the learning task, participants viewed a series of trial-unique scenes (allowing for episodic encoding of each image) in which certain scene categories reliably followed one another (allowing for statistical learning of associations between paired categories). Memory was assessed 24 hr later to isolate stress effects on encoding/learning rather than retrieval. We found modest support for our hypothesis that acute stress can amplify statistical learning: Only participants stressed ∼15 min in advance exhibited reliable evidence of learning across multiple measures. Furthermore, stress-induced cortisol levels predicted statistical learning retention 24 hr later. In contrast, episodic memory did not differ by stress condition, although we did find preliminary evidence that acute stress promoted memory for statistically predictable information and attenuated competition between statistical and episodic encoding. Together, these findings provide initial insights into how stress may differentially modulate learning processes within the hippocampus.

Job burnout, cognitive functioning, and Brain-derived neurotrophic factor expression among hospital Mexican nurses

AIM

To analyze the relationship between burnout syndrome, cognitive functions, and sBDNF (Serum Brain-derived Neurotrophic Factor) in Mexican nurses.

METHOD

A descriptive cross-sectional design was used. This study target staff nurses working in hospitals in Guanajuato, México. Demographic and working condition data were collected via questionnaire. The Maslach Burnout Inventory (MBI) was used to evaluate burnout. A blood sample were collected and processed by ELISA technique to measure sBDNF. Finally, the General Cognitive Assessment (CAB) of the Cognifit© neuropsychological battery was used to evaluated cognitive functions.

RESULTS

Findings showed that there are sociodemographic characteristics and working conditions associated with burnout syndrome among nurses. Furthermore, the data demonstrated a significant decrease in sBDNF levels in burnout nurses and a negative correlation between BDNF levels and burnout syndrome. Additionally, these burnout nurse also revealed significant cognitive impairment in reasoning, memory, and attention as well as total scores of CAB. Interestingly, we found a positive correlation between sBDNF levels and the cognitive deficits in burnout nurse.

CONCLUSION

Reduced BDNF levels could be a biological indicator or part of the pathological process of burnout, which could affect cognitive abilities. Reduced cognitive function in nurses has relevant implications and emphasizes the need for specialized preventive strategies because nurses make clinical decisions concerning their patients, whose situations are constantly changing.

Consistently increased dorsolateral prefrontal cortex activity during the exposure to acute stressors

Stress has a major impact on our mental health. Nonetheless, it is still not fully understood how the human brain responds to ongoing stressful events. Here, we aimed to determine the cortical dynamics during the exposure to ecologically valid, standardized stressors. To this end, we conducted 3 experiments in which healthy participants underwent the Trier Social Stress Test (experiments 1 and 2) and the Socially Evaluated Cold Pressor Test (experiment 3) or a respective control manipulation, while we measured their cortical activity using functional near-infrared spectroscopy. Increases in salivary cortisol and subjective stress levels confirmed the successful stress induction in all experiments. Results of experiment 1 showed significantly increased cortical activity, in particular in the dorsolateral prefrontal cortex, during the exposure to the Trier Social Stress Test. Experiment 2 replicated this finding and showed further that this stress-related increase in dorsolateral prefrontal cortex activity was transient and limited to the period of the Trier Social Stress Test. Experiment 3 demonstrated the increased dorsolateral prefrontal cortex activity during the Socially Evaluated Cold Pressor Test, suggesting that this increase is generalizable and not specific to the Trier Social Stress Test. Together, these data show consistently that dorsolateral prefrontal cortex activity is not reduced, as commonly assumed, but increased under stress, which may promote coping with the ongoing stressor.

The influence of pharmacological mineralocorticoid and glucocorticoid receptor blockade on the cortisol response to psychological stress

The glucocorticoid cortisol is the end product of the hypothalamic-pituitary-adrenal (HPA) axis and crucial for the stress response in humans. Cortisol regulates numerous biological functions by binding to two different types of receptors: the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). Both receptors are found in the brain where they are crucially involved in various mental functions and in feedback inhibition of cortisol release. The precise role of both receptors in the human stress response is not completely understood. In this study, we examined the effects of pharmacological blockade of the MR or the GR on stress-induced cortisol release in a sample of 318 healthy young men (M = 25.42, SD = 5.01). Participants received the MR antagonist spironolactone (300 mg), the GR antagonist mifepristone (600 mg), or a placebo and were subjected 90 min later to a social-evaluative stressor (Trier Social Stress Test) or a non-stressful control condition. We found significantly higher stress-induced cortisol release in the spironolactone group, whereas participants after mifepristone administration did not differ from the control groups. These results suggest that MR blockade results in attenuated fast negative feedback processes and emphasize the important role of the MR during the early phase of the stress response.

The Hypothalamus-Pituitary-Adrenal Axis and Social Cognition in Borderline Personality Disorder

Borderline personality disorder (BPD) is characterized by emotional instability, impulsivity and unstable interpersonal relationships. Patients experience discomforting levels of distress, inducing symptoms like dissociation, aggression or withdrawal. Social situations are particularly challenging, and acute social stress can reduce patients' cognitive and social functioning. In patients with Major Depressive Disorder or Posttraumatic Stress Disorder, which show high comorbidity with BPD, the endocrine stress response is characterized by Hypothalamus-Pituitary-Adrenal (HPA) axis dysfunction, which affects cognitive functioning. Compared to these clinical groups, research on HPA-axis function in BPD is relatively scarce, but evidence points towards a blunted cortisol reactivity to acute stress. Since BPD patients are particularly prone to social stress and experience high subjective difficulties in these situations, it seems plausible that HPA-axis dysregulation might contribute to decreased social cognition in BPD. The present review summarizes findings on the HPA-axis function in BPD and its association with social cognition following acute social stress. For this purpose, we review literature that employed a widely used social stressor (Trier Social Stress Test, TSST) to study the effects of acute social stress on social cognition and the HPA-axis response. We contrast these findings with studies on social cognition that employed Cyberball, another widely used social stressor that lacks HPA-axis involvement. We conclude that research on social cognition in BPD reveals heterogeneous results with no clear relationship between social functioning and HPA-axis response. More research is needed to better understand the psychophysiological underpinnings of impaired social cognition in BPD.

Acute stress reduces attentional blindness: Relations with resting respiratory sinus arrhythmia and cortisol

This study made the first attempt to combine resting respiratory sinus arrhythmia (RSA) and cortisol to provide an explanatory mechanism for the effect of acute stress on emotion-induced blindness (EIB) from the perspective of vagus nerve activity and stress hormone responses. For this purpose, resting electrocardiogram (ECG) signals were recorded first. Participants underwent both the socially evaluated cold-pressor test and control treatments 7 days apart and then completed the EIB task. Heart rate and saliva samples were collected over time. The results demonstrated that acute stress promoted the overall detection of targets. Resting RSA and cortisol levels predicted the stress-induced changes in EIB performance under the negative distractor condition at lag2 negatively and positively, respectively. These findings indicate that the effect of stress on EIB was partially contributed by cortisol, which is more relevant to negative distractor conditions. Resting RSA, as an indicator of inter-individual differences, further provided evidence from the perspective of the trait emotional regulation ability based on the vagus nerve control. In general, resting RSA and cortisol changes over time exhibit different patterns of influence on stress-induced changes in EIB performance. Thus, this study provides a more comprehensive understanding of the effect of acute stress on attentional blindness.

The cortisol switch between vulnerability and resilience

In concert with neuropeptides and transmitters, the end products of the hypothalamus-pituitary-adrenal (HPA) axis, the glucocorticoid hormones cortisol and corticosterone (CORT), promote resilience: i.e., the ability to cope with threats, adversity, and trauma. To exert this protective action, CORT activates mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) that operate in a complementary manner -as an on/off switch- to coordinate circadian events, stress-coping, and adaptation. The evolutionary older limbic MR facilitates contextual memory retrieval and supports an on-switch in the selection of stress-coping styles at a low cost. The rise in circulating CORT concentration after stress subsequently activates a GR-mediated off-switch underlying recovery of homeostasis by providing the energy for restraining the primary stress reactions and promoting cognitive control over emotional reactivity. GR activation facilitates contextual memory storage of the experience to enable future stress-coping. Such complementary MR-GR-mediated actions involve rapid non-genomic and slower gene-mediated mechanisms; they are time-dependent, conditional, and sexually dimorphic, and depend on genetic background and prior experience. If coping fails, GR activation impairs cognitive control and promotes emotional arousal which eventually may compromise resilience. Such breakdown of resilience involves a transition to a chronic stress construct, where information processing is crashed; it leads to an imbalanced MR-GR switch and hence increased vulnerability. Novel MR-GR modulators are becoming available that may reset a dysregulated stress response system to reinstate the cognitive flexibility required for resilience.

Non-instrumental information seeking is resistant to acute stress

Previous research has shown that people intrinsically value non-instrumental information, which cannot be used to change the outcome of events, but only provides an early resolution of uncertainty. This is true even for information about rather inconsequential events, such as the outcomes of small lotteries. Here we investigated whether participants' willingness to pay for non-instrumental information about the outcome of simple coin-flip lotteries with guaranteed winnings was modulated by acute stress. Stress was induced using the Socially Evaluated Cold Pressor Test (SECPT), and information-seeking choices were compared to a warm water control group. Our results neither support the hypothesis that stress decreases information-seeking by directing cognitive resources away from the relevance of the lotteries, nor the opposite hypothesis that stress increases information-seeking by driving anxiety levels up. Instead, we found that despite successful stress induction, as evidenced by increased saliva cortisol levels in the SECPT group, information valuation was remarkably stable. This finding is in line with recent findings that experimentally increased state anxiety did not modulate non-instrumental information seeking. Together, these results suggest that the aversiveness of "not knowing" is a stable cognitive state and not easily modulated by situational context, such as acute stress.

Acute stress impacts reaction times in older but not in young adults in a flanker task

Acute psychosocial stress effects on inhibition have been investigated in young adults, but little is known about these effects in older adults. The present study investigated effects of the Trier Social Stress Test on cognitive inhibition (i.e., ability to ignore distracting information) using a cross-over (stress vs. control) design in healthy young (N = 50; 18-30 years; Mage = 23.06) versus older adults (N = 50; 65-84 years; Mage = 71.12). Cognitive inhibition was measured by a letter flanker task and psychophysiological measures (cortisol, heart rate, subjective stress) validated the stress induction. The results showed that while stress impaired overall accuracy across age groups and sessions, stress (vs. control) made older adults' faster in session 1 and slower in session 2. Given that session 2 effects were likely confounded by practice effects, these results suggest that acute psychosocial stress improved older adults' RTs on a novel flanker task but impaired RTs on a practiced flanker task. That is, the interaction between stress and learning effects might negatively affect response execution when testing older adults on flanker tasks. If confirmed by future research, these results might have important implications especially in settings where repeated cognitive testing is performed under acute stress.

Attenuation of visual exploration following stress

When we explore our surroundings, we frequently move our gaze to collect visual information. Studies have extensively examined gaze behavior in response to different visual scenes. Here, we examined how differences in an individual's state may affect visual exploration, for example, following acute stress. In this study, participants were exposed to either a psychosocial stressor-performing a public speaking task in front of a two-person committee-or a control condition absent stress induction. Elicitation of stress responses was validated using cortisol levels and subjective reports. Stress also led to an extended increase in pupil diameter (a proxy of arousal responses), suggesting it may also affect eye movements. Gaze behavior measures were taken prior and following the stress or control tasks. Acute stress attenuated visual exploration, reflected by fewer saccades and a smaller scanned area. Stress did not have a significant effect on either the tendency to look at social features or at salient regions of the images. These findings diverge from theoretical predictions suggesting that acute stress may facilitate social affiliative behaviors (e.g., Tend-and-Befriend theory). Reduced saccades and a smaller scanned area may be a possible mechanism explaining previous reports showing stress-related effects on various cognitive processes (e.g., visual working memory) that rely on visual exploration.

Using Reappraisal to Improve Outcomes for STEM Teachers and Students

The many stressors associated with teaching can take a toll, resulting in high levels of burnout among teachers and reduced motivation and academic performance among students. This is especially true in the context of science, technology, engineering, and mathematics (STEM) subjects. Despite the efficacy of emotion regulation interventions in pedagogical settings in general and in STEM teaching in particular, there is a lack of suitable interventions. We applied the process model of emotion regulation to STEM teaching and proposed a framework, STEM-Model of EmotioN regulation: Teachers' Opportunities and Responsibilities (STEM-MENTOR), to elucidate how the high demands of STEM teaching and contextual factors (e.g., culture, reforms, teacher-student interactions) may lead to intensified negative emotions and deficits in executive functioning and emotion regulation implementation. Teacher emotions, in turn, shape students' STEM-related achievements and epistemic emotions. Thus, teachers' emotion regulation skills have pervasive effects on teaching outcomes for both teachers and students. We illustrate how at each level of our framework, steps could be taken to improve teachers' emotional trajectory. Our proposed STEM-MENTOR framework has implications for theoretical understanding and may help to shape future interventions that focus on cognitive-emotional processes in STEM education.

What a difference timing makes: Cortisol effects on neural underpinnings of emotion regulation

The ability of emotion regulation under stress is of crucial importance to psychosocial health. Yet, the dynamic function of stress hormones for the cognitive control of emotions over time via non-genomic and genomic cortisol effects remains to be elucidated. In this randomized, double-blind, placebo-controlled neuroimaging experiment, 105 participants (54 men, 51 women) received 20 mg hydrocortisone (cortisol) or a placebo either 30min (rapid, non-genomic cortisol effects) or 90min (slow, genomic cortisol effects) prior to a cognitive reappraisal task including different regulatory goals (i.e., downregulate vs. upregulate negative emotions). On the behavioral level, cortisol rapidly reduced and slowly enhanced emotional responsivity to negative pictures. However, only slow cortisol effects improved downregulation of negative emotions. On the neural level, cortisol rapidly enhanced, but slowly reduced amygdala and dorsolateral prefrontal activation as well as functional connectivity between both structures in the down- minus upregulate contrast. This interaction speaks for an effortful but ineffective regulation of negative emotions during rapid cortisol effects and improved emotion regulation capacities during slow cortisol effects. Taken together, these results indicate a functional shift of cortisol effects on emotion regulation processes over time which may foster successful adaptation to and recovery from stressful life events.

Neural Index of Reinforcement Learning Predicts Improved Stimulus-Response Retention under High Working Memory Load

Human learning and decision-making are supported by multiple systems operating in parallel. Recent studies isolating the contributions of reinforcement learning (RL) and working memory (WM) have revealed a trade-off between the two. An interactive WM/RL computational model predicts that although high WM load slows behavioral acquisition, it also induces larger prediction errors in the RL system that enhance robustness and retention of learned behaviors. Here, we tested this account by parametrically manipulating WM load during RL in conjunction with EEG in both male and female participants and administered two surprise memory tests. We further leveraged single-trial decoding of EEG signatures of RL and WM to determine whether their interaction predicted robust retention. Consistent with the model, behavioral learning was slower for associations acquired under higher load but showed parametrically improved future retention. This paradoxical result was mirrored by EEG indices of RL, which were strengthened under higher WM loads and predictive of more robust future behavioral retention of learned stimulus-response contingencies. We further tested whether stress alters the ability to shift between the two systems strategically to maximize immediate learning versus retention of information and found that induced stress had only a limited effect on this trade-off. The present results offer a deeper understanding of the cooperative interaction between WM and RL and show that relying on WM can benefit the rapid acquisition of choice behavior during learning but impairs retention.SIGNIFICANCE STATEMENT Successful learning is achieved by the joint contribution of the dopaminergic RL system and WM. The cooperative WM/RL model was productive in improving our understanding of the interplay between the two systems during learning, demonstrating that reliance on RL computations is modulated by WM load. However, the role of WM/RL systems in the retention of learned stimulus-response associations remained unestablished. Our results show that increased neural signatures of learning, indicative of greater RL computation, under high WM load also predicted better stimulus-response retention. This result supports a trade-off between the two systems, where degraded WM increases RL processing, which improves retention. Notably, we show that this cooperative interplay remains largely unaffected by acute stress.

Immediate and Delayed Salivary Cytokine Responses during Repeated Exposures to Cold Pressor Stress

INTRODUCTION

Excessive stress is increasingly recognized as an important trigger of many diseases prevalent in modern societies, and monitoring such stress-related effects could aid prevention. The measurement of salivary markers of inflammation is emerging as a promising tool to non-invasively quantify stress' effects on immune processes in everyday life and thereby detect early aberrations before the manifestation of serious health problems. However, more laboratory-controlled research is needed in order to establish the timescale and determinants of salivary cytokine responses to acute stress.

METHODS

We repeatedly exposed participants to Cold Pressor Stress Test (CPT) or a control procedure and measured a wide array of salivary cytokines as well as subjective, cardiovascular, and cortisol stress reactions. CPT exposure was repeated every 15 min, 3 times in total, with a duration of 3 min each. Saliva was sampled immediately after the first two exposures as well as in 15-min intervals until 60 min after the onset of the first intervention.

RESULTS

We found that many cytokines were detectable in saliva. Specific stress effects were limited to IL-8 and IL-6, however, which decreased immediately or 15 min after stress onset, respectively. Moreover, IL-8 was negatively correlated to cortisol output in the stress but not in the control group. Significant increases were also observed in salivary TNFα and IFNγ; however, these effects were similar under both stress and control conditions.

DISCUSSION

Our results show that particular salivary cytokines may be sensitive to immediate effects of acute CPT-induced stress and also highlight the importance of employing control procedures to discern stress effects from unrelated variations in salivary cytokines.

Understanding the relationships between physiological and psychosocial stress, cortisol and cognition

Stress is viewed as a state of real or perceived threat to homeostasis, the management of which involves the endocrine, nervous, and immune systems. These systems work independently and interactively as part of the stress response. The scientific stress literature, which spans both animal and human studies, contains heterogeneous findings about the effects of stress on the brain and the body. This review seeks to summarise and integrate literature on the relationships between these systems, examining particularly the roles of physiological and psychosocial stress, the stress hormone cortisol, as controlled by the hypothalamic-pituitary-adrenal (HPA) axis, and the effects of stress on cognitive functioning. Health conditions related to impaired HPA axis functioning and their associated neuropsychiatric symptoms will also be considered. Lastly, this review will provide suggestions of clinical applicability for endocrinologists who are uniquely placed to measure outcomes related to endocrine, nervous and immune system functioning and identify areas of intervention.

Aversive memory reactivation: A possible role for delta oscillations in the hippocampus-amygdala circuit

Memory labilization, the process by which memories become susceptible to update, is essential for memory reconsolidation and has been a target for novel therapies for traumatic memory-associated disorders. Maternal separation (MS) in male rats produced memories resistant to labilization in adulthood. Based on previous results, we hypothesized that temporal desynchronization between the dorsal hippocampus (DHc) and the basolateral amygdala (BLA), during memory retrieval, could be responsible for this impairment. Our goal was to investigate possible differences in oscillatory activity and synchrony between the DHc and BLA during fear memory reactivation, between MS and non-handled (NH) rats. We used male adult Wistar rats, NH or MS, with electrodes for local field potential (LFP) recordings implanted in the DHc and BLA. Animals were submitted to aversive memory reactivation by exposure to the conditioned context (Reat) or to pseudo-reactivation in a neutral context (pReat), and LFP was recorded. Plasticity markers linked to reconsolidation were evaluated one hour after reactivation. The power of delta oscillations and DHc-BLA synchrony in Reat animals was increased, during freezing. Besides, delta modulation of gamma oscillations amplitude in the BLA was associated with the increase in DHc Zif268 levels, an immediate early gene specifically associated with reconsolidation. Concerning early life stress, we found lower power of delta and strength of delta-gamma oscillations coupling in MS rats, compared to NH, which could explain the low Zif268 levels in a subgroup of MS animals. These results suggest a role for delta oscillations in memory reactivation that should be further investigated.

Stress disrupts insight-driven mnemonic reconfiguration in the medial temporal lobe

Memories are not stored in isolation. Insight into the relationship of initially unrelated events may trigger a flexible reconfiguration of the mnemonic representation of these events. Such representational changes allow the integration of events into coherent episodes and help to build up-to-date-models of the world around us. This process is, however, frequently impaired in stress-related mental disorders resulting in symptoms such as fragmented memories in PTSD. Here, we combined a real life-like narrative-insight task, in which participants learned how initially separate events are linked, with fMRI-based representational similarity analysis to test if and how acute stress interferes with the insight-driven reconfiguration of memories. Our results showed that stress reduced the activity of medial temporal and prefrontal areas when participants gained insight into the link between events. Moreover, stress abolished the insight-related increase in representational dissimilarity for linked events in the anterior part of the hippocampus as well as its association with measures of subsequent memory that we observed in non-stressed controls. However, memory performance, as assessed in a forced-choice recognition test, was even enhanced in the stress group. Our findings suggest that acute stress impedes the neural integration of events into coherent episodes but promotes long-term memory for these integrated narratives and may thus have implications for understanding memory distortions in stress-related mental disorders.

The association between acute stress & empathy: A systematic literature review

Empathy is a fundamental component of our social-emotional experience. Over the last decade, there has been increased interest in understanding the effects of acute stress on empathy. We provide a first comprehensive-and systematic-overview identifying emerging patterns and gaps in this literature. Regarding affective empathy, there is abundant evidence for stress contagion-the 'spillover' of stress from a stressed target to an unstressed perceiver. We highlight contextual factors that can facilitate and/or undermine these effects. Fewer studies have investigated the effects of acute stress on affective empathy, revealing a nuanced picture, some evidence suggests acute stress can block contagion of other's emotions; but again contextual differences need to be considered. Regarding cognitive empathy, most studies find no conclusive effects for simplistic measures of emotion recognition; however, studies using more complex empathy tasks find that acute stress might affect cognitive empathy differentially for men and women. This review provides an important first step towards understanding how acute stress can impact social-togetherness, and aims to aid future research by highlighting (in)congruencies and outstanding questions.

The hippocampus in stress susceptibility and resilience: Reviewing molecular and functional markers

Understanding the individual variability that comes with the likelihood of developing stress-related psychopathologies is of paramount importance when addressing mechanisms of their neurobiology. This article focuses on the hippocampus as a region that is highly influenced by chronic stress exposure and that has strong ties to the development of related disorders, such as depression and post-traumatic stress disorder. We first outline three commonly used animal models that have been used to separate animals into susceptible and resilient cohorts. Next, we review molecular and functional hippocampal markers of susceptibility and resilience. We propose that the hippocampus plays a crucial role in the differences in the processing and storage of stress-related information in animals with different stress susceptibilities. These hippocampal markers not only help us attain a more comprehensive understanding of the various facets of stress-related pathophysiology, but also could be targeted for the development of new treatments.

Reappraisal enhances memory formation for a stressful episode

Emotion regulation strategies have been shown to modify the physiological response to stress, yet whether these strategies can modulate also cognitive responses to stress is largely unknown. A prominent cognitive response to stress is the enhanced memory formation for the stressful event, which is an adaptive mechanism to prepare for similar events in the future. Thus, the present study aimed to investigate whether emotion regulation strategies impact the memory formation for a stressful episode. In a two-day study, participants (n = 124) underwent an enriched stressful episode or a control episode. Critically, before the exposure to the stressor, they were instructed to use a suppression or reappraisal strategy during the stressful episode. One week later, participants completed a memory test for central and peripheral details of this episode. Our results show that reappraisal enhanced not only the cortisol response to the stressor but also the memory formation for central features of the stressful episode. This reappraisal-related boost of memory for the stressor was particularly pronounced in participants' with high working memory capacity. These findings show that reappraisal may not only impact the physiological response to a stressful event but also the cognitive representation of this event in memory.

Using expectation violation models to improve the outcome of psychological treatments

Expectations are a central maintaining mechanism in mental disorders and most psychological treatments aim to directly or indirectly modify clinically relevant expectations. Therefore, it is crucial to examine why patients with mental disorders maintain dysfunctional expectations, even in light of disconfirming evidence, and how expectation-violating situations should be created in treatment settings to optimize treatment outcome and reduce the risk of treatment failures. The different psychological subdisciplines offer various approaches for understanding the underlying mechanisms of expectation development, persistence, and change. Here, we convey recommendations on how to improve psychological treatments by considering these different perspectives. Based on our expectation violation model, we argue that the outcome of expectation violation depends on several characteristics: features of the expectation-violating situation; the dynamics between the magnitude of expectation violation and cognitive immunization processes; dealing with uncertainties during and after expectation change; controlled and automatic attention processes; and the costs of expectation changes. Personality factors further add to predict outcomes and may offer a basis for personalized treatment planning. We conclude with a list of recommendations derived from basic psychology that could contribute to improved treatment outcome and to reduced risks of treatment failures.

Spironolactone as a potential new pharmacotherapy for alcohol use disorder: convergent evidence from rodent and human studies

Evidence suggests that spironolactone, a nonselective mineralocorticoid receptor (MR) antagonist, modulates alcohol seeking and consumption. Therefore, spironolactone may represent a novel pharmacotherapy for alcohol use disorder (AUD). In this study, we tested the effects of spironolactone in a mouse model of alcohol drinking (drinking-in-the-dark) and in a rat model of alcohol dependence (vapor exposure). We also investigated the association between spironolactone receipt for at least 60 continuous days and change in self-reported alcohol consumption, using the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C), in a pharmacoepidemiologic cohort study in the largest integrated healthcare system in the US. Spironolactone dose-dependently reduced the intake of sweetened or unsweetened alcohol solutions in male and female mice. No effects of spironolactone were observed on drinking of a sweet solution without alcohol, food or water intake, motor coordination, alcohol-induced ataxia, or blood alcohol levels. Spironolactone dose-dependently reduced operant alcohol self-administration in dependent and nondependent male and female rats. In humans, a greater reduction in alcohol consumption was observed among those who received spironolactone, compared to propensity score-matched individuals who did not receive spironolactone. The largest effects were among those who reported hazardous/heavy episodic alcohol consumption at baseline (AUDIT-C ≥ 8) and those exposed to ≥ 50 mg/day of spironolactone. These convergent findings across rodent and human studies demonstrate that spironolactone reduces alcohol use and support the hypothesis that this medication may be further studied as a novel pharmacotherapy for AUD.

Stress can lead to an increase in smartphone use in the context of texting while walking

Texting while walking (TWW) is a dangerous behavior that can lead to injury and even death. While several studies have examined the relationship between smartphone use and stress, to our knowledge no studies have yet investigated the relationship between stress and TWW. The objective of the present study was to investigate this relationship by examining the effects of stress on TWW, the effects of TWW on subsequent stress, and the effect of stress on multitasking performance. A total of 80 participants completed two sequential tasks in a laboratory while they walked on a treadmill and responded to a biological motion stimulus imitating the movement of another pedestrian. In the unrestricted task, participants were given the choice to use their personal phones. In the controlled task, they carried a text conversation with a research assistant while they walked and responded to the stimulus. Stress was measured via questionnaire and saliva collection for measure of cortisol (a stress hormone) before and after each task. Results show that greater psychological stress and cortisol variations were associated with a greater number of phone uses during the unrestricted task. Greater phone use during the unrestricted task was associated with lower subsequent psychological stress in women and total time of phone use was correlated with subsequent cortisol levels. Stress measured before the controlled task had no effect on multitasking performance, but participants with moderate performance were those with the highest cortisol levels. Our results suggest that stress could be a precursor to TWW and that it could affect a pedestrian’s ability to stay safe when using their smartphone.

Feeling rushed? Perceived time pressure impacts executive function and stress

Executive function (EF) is critical to everyday life, but it can be undermined by adverse psychological states like stress and negative affect. For example, inadequate time to perform a task is a common stressor that can disrupt EF. Although the impact of actual time pressure on EF has been established, little is known about how self-generated, perceived time pressure (PTP) affects EF in the absence of objective time limits. We chose Eriksen’s Flanker task as an index of cognitive inhibition, a key component of EF, and we varied the interval between successive trials, the inter-trial interval (ITI), to proxy PTP. This manipulation strongly impacted task performance: shrinking the ITI to increase PTP diminished cognitive inhibition and increased both stress and negative affect. Subsequently lengthening the ITI to decrease PTP reversed nearly all of these effects, except stress, which persisted. Multilevel linear regression modeling revealed that ITI and stress predicted inhibition, and exploratory mediation modeling suggested that stress mediates the relationship between ITI and inhibition. These findings validate perceived time pressure as an empirical stressor and demonstrate EF’s sensitivity to changes in PTP.

Estimation Strategy Selection Is Modulated by Snapshot Emotional Priming, but Not Math Anxiety

The present study explored the role of snapshot emotional priming and math anxiety in estimation strategy selection. Participants were asked to complete a two-digit multiplication estimation task (e.g., 34 × 67) under explicit (Experiment 1) and implicit (Experiment 2) snapshot emotional priming conditions by freely choosing to use DU (down-up, e.g., doing 30 × 70 = 2100 for 34 × 67) or UD (up-down, e.g., doing 40 × 60 = 2400 for 34 × 67) strategies to arrive as close as possible to the correct answer. In Experiment 1, individuals' estimation performance was positively influenced by explicit happy priming (shorter RT (reaction time)), while not affected by explicit fear priming. In Experiment 2, individuals' estimation ACC (accuracy) when using the UD strategy was negatively affected by both implicit happy and fear priming, but their RT when using DU and UD strategies was positively impacted by implicit happy priming. In both experiments, the correlations between math anxiety and estimation performance (ACC, RT, and strategy selection adaptivity) was not significant. The present study suggests that fear priming was not always detrimental to individuals' estimation performance, and happy priming did not always universally improve individuals' estimation performance. Additionally, estimation strategy selection was not influenced by math anxiety.

Stress effects on the top-down control of visuospatial attention: Evidence from cue-dependent alpha oscillations

Stress is assumed to inhibit the top-down control of attention and to facilitate bottom-up processing. Evidence from human experiments, however, remains scarce. Previous studies have addressed how stress affects the interplay of bottom-up and top-down mechanisms of attention. A key open question is in how far such effects can actually be attributed to a stress-induced modulation of top-down attention control. We sought to isolate top-down from bottom-up effects by assessing stress effects on anticipatory changes in alpha oscillations that precede stimulus processing. Participants performed in a cued target detection task in which a cue prompted them to covertly shift their attention to left or right screen positions, 20 min after being exposed to the bilateral feet cold pressor test or a warm water control procedure. The stressor led to a substantial increase in cortisol, peaking 20 min post stressor, along with rises in heart rate, blood pressure, and subjective ratings of stress and arousal. As expected, cued attention deployment led to higher alpha power over posterior electrodes contralateral versus ipsilateral to the attended hemifield during the cue-target interval. Importantly, this purely endogenous effect was potentiated by stress, however, significant differences were restricted to the middle of the cue-target interval and thus temporally separated from the appearance of the target. These results indicate that stress does not impair top-down attentional control per se but may introduce a qualitative change modulating the way attention is deployed to meet action goals.

Effects of psychological stress and cortisol on decision making and modulating factors: a systematic review

Evidence suggests that psychological stress has effects on decision making, but the results are inconsistent, and the influence of cortisol and other modulating factors remains unclear. Based on the PRISMA criteria, 18 studies carried out between 2015 and 2020 that examined the effects of psychological stress on decision making and measured cortisol levels were selected. Eight studies employed uncertainty-based economic tasks, five studies used decision-making tasks in hypothetical situations that can be encountered in real life or in a specific setting, and five studies employed prosocial decision tasks. Seventeen studies assessed acute stress, and two assessed chronic stress; eight evaluated the influence of sex. Most of the studies that explored the association between stress and decision making using uncertainty-based economic tasks found statistically significant differences as a function of stress exposure and the cortisol response to stress, whereas most of the studies that employed non-economic decision-making tasks in hypothetical situations did not find statistically significant differences. When prosocial decision making was evaluated, more altruistic decisions were found after acute stress, and these decisions were positively associated with cortisol. Half of the studies that assessed the role of sex observed a greater impact on decision making after stress in women. Results suggest that it is important to consider modulating factors - the type of decision-making task, the cortisol response to stress, the characteristics of the psychological stressor, or the subject's sex - when trying to understand psychosocial stress phenomena.

Altruism under Stress: Cortisol Negatively Predicts Charitable Giving and Neural Value Representations Depending on Mentalizing Capacity

Altruism, defined as costly other-regarding behavior, varies considerably across people and contexts. One prominent context in which people frequently must decide on how to socially act is under stress. How does stress affect altruistic decision-making and through which neurocognitive mechanisms? To address these questions, we assessed neural activity associated with charitable giving under stress. Human participants (males and females) completed a charitable donation task before and after they underwent either a psychosocial stressor or a control manipulation, while their brain activity was measured using functional magnetic resonance imaging. As the ability to infer other people's mental states (i.e., mentalizing) predicts prosocial giving and may be susceptible to stress, we examined whether stress effects on altruism depend on participants' general capacity to mentalize, as assessed in an independent task. Although our stress manipulation per se had no influence on charitable giving, increases in the stress hormone cortisol were associated with reductions in donations in participants with high mentalizing capacity, but not in low mentalizers. Multivariate neural response patterns in the right dorsolateral prefrontal cortex (DLPFC) were less predictive of postmanipulation donations in high mentalizers with increased cortisol, indicating decreased value coding, and this effect mediated the (moderated) association between cortisol increases and reduced donations. Our findings provide novel insights into the modulation of altruistic decision-making by suggesting an impact of the stress hormone cortisol on mentalizing-related neurocognitive processes, which in turn results in decreased altruism. The DLPFC appears to play a key role in mediating this cortisol-related shift in altruism.SIGNIFICANCE STATEMENT Altruism is a fundamental building block of our society. Emerging evidence indicates a major role of acute stress and stress-related neuromodulators in social behavior and decision-making. How and through which mechanisms stress may impact altruism remains elusive. We observed that the stress hormone cortisol was linked to diminished altruistic behavior. This effect was mediated by reduced value representations in the right dorsolateral prefrontal cortex and critically depended on the individual capacity to infer mental states of others. Our findings provide novel insights into the modulation of human altruism linked to stress-hormone dynamics and into the involved sociocognitive and neural mechanisms, with important implications for future developments of more targeted interventions for stress-related decrements in social behavior and social cognition.

How exposure to chronic stress contributes to the development of type 2 diabetes: A complexity science approach

Chronic stress contributes to the onset of type 2 diabetes (T2D), yet the underlying etiological mechanisms are not fully understood. Responses to stress are influenced by earlier experiences, sex, emotions and cognition, and involve a complex network of neurotransmitters and hormones, that affect multiple biological systems. In addition, the systems activated by stress can be altered by behavioral, metabolic and environmental factors. The impact of stress on metabolic health can thus be considered an emergent process, involving different types of interactions between multiple variables, that are driven by non-linear dynamics at different spatiotemporal scales. To obtain a more comprehensive picture of the links between chronic stress and T2D, we followed a complexity science approach to build a causal loop diagram (CLD) connecting the various mediators and processes involved in stress responses relevant for T2D pathogenesis. This CLD could help develop novel computational models and formulate new hypotheses regarding disease etiology.

Brain Mineralocorticoid receptor in health and disease: from molecular signaling to cognitive and emotional function

Brain mineralocorticoid receptors (MR) mediate effects of glucocorticoid hormones in stress adaptation, as well as the effects of aldosterone itself in relation to salt homeostasis. Brain stem MRs respond to aldosterone, whereas forebrain MRs mediate rapid and delayed glucocorticoid effects in conjunction with the glucocorticoid receptor (GR). MR‐mediated effects depend on age, gender, genetic variations, and environmental influences. Disturbed MR activity through chronic stress, certain (endocrine) diseases or during glucocorticoid therapy can cause deleterious effects on affective state, cognitive and behavioural function in susceptible individuals. Considering the important role MR plays in cognition and emotional function in health and disease, MR modulation by pharmacological intervention could relieve stress‐ and endocrine‐related symptoms. Here, we discuss recent pharmacological interventions in the clinic and genetic developments in the molecular underpinnings of MR signalling. Further understanding of MR‐dependent pathways may help to improve psychiatric symptoms in a diversity of settings.

Mechanisms of memory under stress

It is well established that stress has a major impact on memory, driven by the concerted action of various stress mediators on the brain. Recent years, however, have seen considerable advances in our understanding of the cellular, neural network, and cognitive mechanisms through which stress alters memory. These novel insights highlight the intricate interplay of multiple stress mediators, including-beyond corticosteroids, catecholamines, and peptides-for instance, endocannabinoids, which results in time-dependent shifts in large-scale neural networks. Such stress-induced network shifts enable highly specific memories of the stressful experience in the long run at the cost of transient impairments in mnemonic flexibility during and shortly after a stressful event. Based on these recent discoveries, we provide a new integrative framework that links the cellular, systems, and cognitive mechanisms underlying acute stress effects on memory processes and points to potential targets for treating aberrant memory in stress-related mental disorders.

Non-genomic steroid signaling through the mineralocorticoid receptor: Involvement of a membrane-associated receptor?

Corticosteroid receptors in the mammalian brain mediate genomic as well as non-genomic actions. Although receptors mediating genomic actions were already cloned 35 years ago, it remains unclear whether the same molecules are responsible for the non-genomic actions or that the latter involve a separate class of receptors. Here we focus on one type of corticosteroid receptors, i.e. the mineralocorticoid receptor (MR). We summarize some of the known properties and the current insight in the localization of the MR in peripheral cells and neurons, especially in relation to non-genomic signaling. Previous studies from our own and other labs provided evidence that MRs mediating non-genomic actions are identical to the ones involved in genomic signaling, but may be translocated to the plasma cell membrane instead of the nucleus. With fixed cell imaging and live cell imaging techniques we tried to visualize these presumed membrane-associated MRs, using antibodies or overexpression of MR-GFP in COS7 and hippocampal cultured neurons. Despite the physiological evidence for MR location in or close to the cell membrane, we could not convincingly visualize membrane localization of endogenous MRs or GFP-MR molecules. However, we did find punctae of labeled antibodies intracellularly, which might indicate transactivating spots of MR near the membrane. We also found some evidence for trafficking of MR via beta-arrestins. In beta-arrestin knockout mice, we didn't observe metaplasticity in the basolateral amygdala anymore, indicating that internalization of MRs could play a role during corticosterone activation. Furthermore, we speculate that membrane-associated MRs could act indirectly via activating other membrane located structures like e.g. GPER and/or receptor tyrosine kinases.

Acute stress influences strategy preference when dealing with high intensity emotions in men

Stress has been shown to initiate a shift from flexible to rigid, less demanding cognitive processes. Reappraisal and distraction are two emotion regulation strategies varying in their cognitive demands. Previous studies indicate that stress improves regulatory performances of high arousal stimuli. We thus investigated whether acute stress alters the preference for reappraisal or distraction when downregulating emotions of different intensities and further explored its influence on regulatory outcomes. Eighty males were either socially stressed (n=40) or exposed to a control condition (n=40) prior to an emotion regulation choice paradigm. Stress increased the probability to prefer distraction for downregulating high intensity emotions. Stressed (vs. control) participants reported to be generally more successful in regulating high intensity emotions, which was positively associated with cortisol but not alpha-amylase increases. Our findings provide initial evidence that stress fosters a preference for less demanding regulatory options, suggesting favorable strategy choices in response to acute stressors. DATA AVAILABILITY: The data that support the findings of this study are available at the Open Science Framework (OSF) under https://osf.io/b9ae3/.

Does older adults' cognition particularly suffer from stress? A systematic review of acute stress effects on cognition in older age

This literature review provides the first comprehensive qualitative and quantitative systematic synthesis of acute laboratory stress effects on older adults' cognition by specifying the direction and magnitude of those effects both overall and for different cognitive processes separately. A systematic literature search was performed, and effect sizes estimated whenever possible. We found meta-analytical evidence that stress has negative effects on older adults' verbal fluency (g_adj = -0.53, 95 % CI [-2.70, 1.63]), null-to-negative effects on episodic memory (g_adj = -0.26, 95 % CI [-0.44, -0.08]), null effects on executive functions (g_adj = 0.07, 95 % CI [-0.31, 0.46]), and enhancing effects on working memory (g_adj = 0.16, 95 % CI [-0.01, 0.33]). Relating these findings to those in young adults, notable differences emerged for some cognitive functions, such as opposing effects on working memory between age groups. Our review further reveals that stress effects on older adults' memory retention, associative memory, prospective memory, interference control or cognitive flexibility are heavily understudied. We provide a conceptual and methodological framework for future studies in older adults.

The effects of acute stress on attentional networks and working memory in females

Neurobiological models indicate that acute stress facilitates bottom-up stimulus processing while impairing top-down executive control. To test this hypothesis, the present study investigated the effects of acute stress on behavioural and electrophysiological measures of human attentional networks, and behavioural measures of working memory. Forty-five female participants (M_age = 22.1, SD = 2.4) performed the Attention Network Test (ANT) and the n-back task before and after the Maastricht Acute Stress Test (MAST; n = 23) or a non-stressful MAST-placebo (n = 22). Subjective distress ratings and salivary cortisol concentrations revealed a successful stress induction. Increased salivary cortisol at baseline was associated with slower reaction times across both tasks, suggesting a general detrimental effect of cortisol on cognitive functioning. Despite these findings, however, the hypothesised effects of the acute stress manipulation were not found for either task. Supplementary analyses indicated that these results were unrelated to the magnitude or duration of the stress response. Our results therefore suggest the standard version of the ANT may be insensitive to the effects of acute stress, and that higher cognitive loads may be necessary to observe stress effects on the n-back task.

You Are What You Repeatedly Do: Links Between Personality and Habit

Several socio-cognitive theories of personality describe habit development as an integral process of personality development. Yet, no empirical research has rigorously examined linkages between personality traits and habits. In the present study, participants (N=459) reported perceived automaticity, intrinsic rewards, and extrinsic rewards for several of 25 total behaviors; they also self-reported two important traits: conscientiousness and neuroticism. Conditional multilevel mediation analyses were used to assess the effect of each conscientiousness and neuroticism on automaticity through intrinsic and extrinsic rewards for each behavior. Across behaviors, conscientiousness was negatively associated with behavioral automaticity, and neuroticism positively predicted it. Specifically, conscientiousness appeared to protect against automaticity for health risk behaviors but did not promote automaticity for behaviors performed frequently by those high in conscientiousness; conversely, neuroticism positively predicted automaticity even for behaviors not performed more frequently by those high on the trait. Perceived intrinsic and extrinsic rewards mediated the link between traits and automaticity for some behaviors (e.g., sugary drink consumption), but these effects were not consistent across all behaviors. These findings offer some of the first empirical insights into the links between personality and habits.

A role for GABA in the modulation of striatal and hippocampal systems under stress

Previous research has demonstrated that stress modulates the competitive interaction between the hippocampus and striatum, two structures known to be critically involved in motor sequence learning. These earlier investigations, however, have largely focused on blood oxygen-level dependent (BOLD) responses. No study to date has examined the link between stress, motor learning and levels of striatal and hippocampal gamma-aminobutyric acid (GABA). This knowledge gap is surprising given the known role of GABA in neuroplasticity subserving learning and memory. The current study thus examined: a) the effects of motor learning and stress on striatal and hippocampal GABA levels; and b) how learning- and stress-induced changes in GABA relate to the neural correlates of learning. To do so, fifty-three healthy young adults were exposed to a stressful or non-stressful control intervention before motor sequence learning. Striatal and hippocampal GABA levels were assessed at baseline and post-intervention/learning using magnetic resonance spectroscopy. Regression analyses indicated that stress modulated the link between striatal GABA levels and functional plasticity in both the hippocampus and striatum during learning as measured with fMRI. This study provides evidence for a role of GABA in the stress-induced modulation of striatal and hippocampal systems.

The association of the 5-HTTLPR polymorphism and the response to different stressors in healthy males

The experience of stress is related to individual wellbeing and vulnerability to psychopathology. Therefore, understanding the determinants of individual differences in stress reactivity is of great concern from a clinical perspective. The functional promotor polymorphism of the serotonin transporter gene (5-HTTLPR/rs25531) is such a factor, which has been linked to the acute stress response as well as the adverse effect of life stressors. In the present study, we compared the impact of two different stress induction protocols (Maastricht Acute Stress Test and ScanSTRESS) and the respective control conditions on affective ratings, salivary cortisol levels and cognitive performance. To this end, 156 healthy young males were tested and genotyped for the 5-HTTLPR/rs25531 polymorphism. While combined physiological and psychological stress in the MAST led to a greater cortisol increase compared to control conditions as well as the psychosocial ScanSTRESS, subjective stress ratings were highest in the ScanSTRESS condition. Stress induction in general affected working memory capacity but not response inhibition. Subjective stress was also influenced by 5-HTTLPR/rs25531 genotype with the high expression group showing lower stress ratings than lower expression groups. In line with previous research, we identified the low expression variant of the serotonin transporter gene as a risk factor for increased stress reactivity. While some dimensions of the human stress response may be stressor specific, cognitive outcomes such as working memory performance are influenced by stress in general. Different pathways of stress processing and possible underlying mechanisms are discussed.

Stress-induced bias of multiple memory systems during retrieval depends on training intensity

Stressful events promote a shift from hippocampus-dependent 'cognitive' learning towards dorsal striatum-dependent 'habit' learning. Beyond modulating the recruitment of multiple memory systems during learning, recent evidence suggests that stress may also affect which of these memory systems is employed during retrieval, thereby affecting the nature of remembering. However, while some studies reported increased reliance on 'habit' memory retrieval after stress, other studies suggested even a bias towards 'cognitive' memory retrieval after stress. In the present experiment, we tested the hypothesis that the nature of the stress effect on the control of memory retrieval depends on the extent of initial training. To this end, participants completed a probabilistic classification learning (PCL) task that can be solved by both the 'cognitive' and the 'habit' memory systems, which is reflected in the engagement of specific behavioral strategies. Critically, participants received either moderate (100 trials) or intensive (200 trials) training in the PCL task. Participants then underwent a stress protocol or a non-stressful control procedure, before they completed a retrieval version of the PCL task. The effectiveness of the stress manipulation was verified by increases in salivary cortisol and autonomic arousal. Our results further revealed that participants who received moderate training showed, during retrieval, a stress-induced shift towards strategies indicative of the dorsal striatal 'habit' memory system. After prolonged training, however, stress did not affect which memory system guided retrieval. The present results indicate that the effect of stress on the engagement of multiple memory systems during retrieval is critically dependent on the extent of initial training and, by inference, on the strength of the multiple memory traces established during learning.

Brain preparedness: The proactive role of the cortisol awakening response in hippocampal-prefrontal functional interactions

Upon awakening from nighttime sleep, the stress hormone cortisol in humans exhibits a robust rise within thirty to forty-five minutes. This cortisol awakening response (CAR), a crucial point of reference within the healthy cortisol circadian rhythm, has been linked to various psychological, psychiatric and health-related conditions. The CAR is thought to prepare the brain for anticipated challenges of the upcoming day to maintain one's homeostasis and promote adaptive responses. Using brain imaging with a prospective design and pharmacological manipulation, we investigate the neurobiological mechanisms underlying this preparation function of the CAR across two studies. In Study 1, a robust CAR is predictive of less hippocampal and prefrontal activity, though enhanced functional coupling between those regions during a demanding task hours later in the afternoon. Reduced prefrontal activity is in turn linked to better working memory performance, implicating that the CAR proactively promotes brain preparedness based on improved neurocognitive efficiency. In Study 2, pharmacologically suppressed CAR using Dexamethasone mirrors this proactive effect, which further causes a selective reduction of prefrontal top-down functional modulation over hippocampal activity. These findings establish a causal link between the CAR and its proactive role in optimizing functional brain networks involved in neuroendocrine control, executive function and memory.