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

Effects of blue light during and after exposure on auditory working memory

INTRODUCTION

Exposure to short-wavelength light (i.e., blue light) has been shown to enhance cognitive function in humans. While most prior studies have focused on visuospatial working memory, the effects of blue light on auditory working memory, particularly tasks involving the phonological loop, remain underexplored. This study investigated both the during- and post-exposure effects of blue light on auditory memory performance.

METHODS

Fifteen healthy university students (13 males, 2 females; 21.47 ± 1.06 years old) participated in a randomized crossover design. Each participant was exposed to three lighting conditions for approximately 20-min: blue (λmax = 476 nm, illuminance = 21.84 lx, 13.8 log photons/s-1.cm-2, melanopic EDI = 169.68 lx), amber (λmax = 580 nm, illuminance = 61.65 lx, 13.5 log photons/s-1.cm-2, melanopic EDI = 2.87 lx) and dim light (baseline; illuminance < 5.00 lx). Each session was separated by a one-week washout period. To mitigate order effects, the sequence of light conditions was randomized across participants. The modified version of the Sternberg working memory task was performed during light exposure and after a 10-min break (i.e., During- vs Post-exposure phase). The accuracy, reaction time, subject anxiety and subject sleepiness were measured.

RESULTS

In the post-exposure phase, blue light significantly improved accuracy compared to amber (p < 0.01, d = 0.66) and dim light (p < 0.01, d = 0.67). No significant differences were observed during exposure or in reaction time across three light conditions. Anxiety levels were significantly higher during blue light exposure (vs. amber: p = 0.013, d = 0.96; vs. dim: p = 0.027, d = 0.83), while sleepiness remained unchanged.

CONCLUSIONS

Blue light exposure may enhance auditory working memory accuracy with a delayed effect, independent of vigilance or processing speed. While these findings are promising, the observed effects are preliminary and require validation in larger and more diverse populations.

Smartphone-based Monitoring and cognition Modification Against Recurrence of Depression (SMARD): An RCT of Memory Bias Modification Training vs. Cognitive Control Training vs. Attention Bias Modification Training in remitted recurrently depressed patients with 1.5 year follow-up

BACKGROUND

Major Depressive Disorder (MDD) has a 50-80% recurrence rate highlighting the urgent need for more efficient recurrence prevention programs. Currently, recurrences are often identified too late, while existing preventive strategies may not sufficiently address ethio-patho-physiological mechanisms for recurrence. Negative memory bias (the tendency to better remember negative than positive events), negative attention bias (selective attention favoring mood-congruent information), and cognitive control deficits are important factors involved in the onset, maintenance, and recurrence of depressive episodes.

METHODS

Here we describe the protocol for the Smartphone-based Monitoring and cognition Modification Against Recurrence of Depression (SMARD) study, aiming to investigate different forms of cognitive training programs administered via smartphones, in order to develop a second-generation recurrence prevention program. In addition, we will gather Experience Sampling Method (ESM) assessments during a 6-day period, and during the follow-up period we will obtain behavioral data on (social) activities with BEHAPP, a smartphone-based Mobile Passive Monitoring application for remote behavioral monitoring to identify behavioral changes indicative of an imminent depressive episode. In a randomized controlled trial, SMARD will compare the effects of a smartphone-based Memory Bias Modification Training (MBT), Cognitive Control Training (CCT), and Attention Bias Modification Training (ABT) versus cognitive domain-specific (active-) sham trainings in 120 remitted MDD-patients with recurrent-MDD. Over the course of three weeks, participants receive multiple daily training sessions. Thereafter, participants will be followed up for 1.5 years with 3-monthly interviews to assess recurrences.

DISCUSSION

The SMARD study aims to 1. assess the effects of the cognitive training programs versus their training-specific (active-) sham conditions on changes in memory, cognitive control dysfunction and attention; 2. relate training effects to neural networks previously identified in (recurrence of) MDD (therefore we obtain functional Magnetic Resonance Imaging ((f)MRI) scans before and after the training in a subset of participants); 3. link baseline and change in memory, cognitive control, attention and neural functioning, and ESM data to prospective recurrences; 4. examine whether passive smartphone-use monitoring can be used for prediction of recurrences.

TRIAL REGISTRATION

NL-OMON26184 and NL-OMON27513. Registered 12 August 2021-Retrospectively registered,  https://onderzoekmetmensen.nl/en/trial/26184 en https://onderzoekmetmensen.nl/en/trial/27513 .

Effects of voluntary or involuntary exercise in adolescent male rats exposed to chronic social isolation on cognition, behavior, and neurotrophic factors

This study investigated the effects of voluntary and involuntary/regular exercise on neurotrophic factors in the brain, cognitive functions, and anxiety in socially isolated adolescent male rats. In this study, 42 adolescent male Sprague-Dawley rats were divided into six groups: control (C), socially isolated (SI), voluntary exercise (VE), regular exercise (RE), socially isolated + voluntary exercise (SI-VE), and socially isolated + regular exercise (SI-RE). Socially isolated groups were kept in separate cages for 4 weeks. Treadmill and wheel running were used in the exercise groups. The following behavioral tests-elevated plus maze (EPM), open field, ultrasonic vocalization (USV), and Morris water maze (MWM)-rats were euthanized, and brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and vascular endothelial growth factor (VEGF) levels were measured in the prefrontal cortex (PFC) and hippocampus. Statistically, the differences between the groups were evaluated by one-way ANOVA and post hoc LSD tests using IBM SPSS software. In the EPM, locomotor activity was higher in the voluntary exercise groups. In the MWM, both regular exercise groups found the platform faster. In the USV, the SI-RE group produced more 50-kHz sounds. BDNF and NGF levels in the hippocampus were higher in the SI-RE and SI-VE groups; VEGF levels were higher in the SI-RE group. Neuron density in the PFC increased in the SI-RE and VE groups, while neuron density in the hippocampus increased in the SI-RE, SI-VE, and VE groups. According to the findings, we showed that voluntary exercise reduces social isolation-induced anxiety, and involuntary/regular exercise both reduces anxiety and has potential benefits on cognitive functions.

I "Gut" Rhythm: the microbiota as a modulator of the stress response and circadian rhythms

Modern habits are becoming more and more disruptive to health. As our days are often filled with circadian disruption and stress exposures, we need to understand how our responses to these external stimuli are shaped and how their mediators can be targeted to promote health. A growing body of research demonstrates the role of the gut microbiota in influencing brain function and behavior. The stress response and circadian rhythms, which are essential to maintaining appropriate responses to the environment, are known to be impacted by the gut microbiota. Gut microbes have been shown to alter the host's response to stress and modulate circadian rhythmicity. Although studies demonstrated strong links between the gut microbiota, circadian rhythms and the stress response, such studies were conducted in an independent manner not conducive to understanding the interface between these factors. Due to the interconnected nature of the stress response and circadian rhythms, in this review we explore how the gut microbiota may play a role in regulating the integration of stress and circadian signals in mammals and the consequences for brain health and disease.

Mapping brain neural networks in stress brain connectivity

Stress can cause severe damage to the CNS and contribute to an increased risk of neurological and psychiatric disorders. Gaining more insight into the neurobiology of stress is essential to treating neurological disorders associated with stress, which account for a high percentage of the world's disease burden. However, because of complicated variations in stressor types, stress perception, and preceding exposure to stressors, studying the impacts of stress is challenging. Gender, age, and timing are other crucial variables that can influence the stress response. Behavioral, physiological, genetic, and cellular/molecular neuroscience methodologies have all been widely applied in various research contexts to examine the neurobiological impacts of stress. Furthermore, because these approaches are invasive and hence undesirable or impractical for use in humans, they are frequently challenging to adapt to a therapeutic context. As an alternative to invasive procedures, functional neuroimaging approaches are starting to be developed. We discuss in this chapter brain neural networks under stress brain connection.

The elevated open platform stress suppresses excitatory synaptic transmission in the layer V anterior cingulate cortex

There are various forms of stress including; physical, psychological and social stress. Exposure to physical stress can lead to physical sensations (e.g. hyperalgesia) and negative emotions including anxiety and depression in animals and humans. Recently, our studies in mice have shown that acute physical stress induced by the elevated open platform (EOP) can provoke long-lasting mechanical hypersensitivity. This effect appears to be related to activity in the anterior cingulate cortex (ACC) at the synaptic level. Indeed, EOP exposure induces synaptic plasticity in layer II/III pyramidal neurons from the ACC. However, it is still unclear whether or not EOP exposure alters intrinsic properties and synaptic transmission in layer V pyramidal neurons. This is essential because these neurons are known to be a primary output to subcortical structures which may ultimately impact the behavioral stress response. Here, we studied both intrinsic properties and excitatory/inhibitory synaptic transmission by using whole-cell patch-clamp method in brain slice preparations. The EOP exposure did not change intrinsic properties including resting membrane potentials and action potentials. In contrast, EOP exposure suppressed the frequency of miniature and spontaneous excitatory synaptic transmission with an alteration of kinetics of AMPA/GluK receptors. EOP exposure also reduced evoked synaptic transmission induced by electrical stimulation. Furthermore, we investigated projection-selective responses of the mediodorsal thalamus to the layer V ACC neurons. EOP exposure produced short-term depression in excitatory synaptic transmission on thalamo-ACC projections. These results suggest that the EOP stress provokes abnormal excitatory synaptic transmission in layer V pyramidal neurons of the ACC.

Revisiting Cognitive Deficits in Outpatients with Psychotic Disorders: A Transdiagnostic Comparison of Cognitive Performance While Accounting for Putative Confounding Factors

Recent research suggests that cognitive deficits in individuals with psychotic disorders could be overestimated because poor cognitive test performance is partly attributable to non-cognitive factors. To further test this, we included non-hospitalized individuals with psychotic disorders (PSY, n = 38), individuals with attenuated psychotic symptoms (n = 40), individuals with obsessive-compulsive disorders (n = 39), and healthy controls (n = 38). Relevant cognitive domains were assessed using the MATRICS Consensus Cognitive Battery. Putative confounding non-cognitive factors-heart rate, self-reported stress, negative affect, performance-related beliefs, and actigraphy-derived sleep-were assessed before cognitive testing. A multivariate analysis of covariance was calculated to examine group differences in cognitive performance while controlling for non-cognitive factors. PSY showed decreased test performance in graphomotor speed, attention, and verbal tasks compared to the other groups, whereas non-verbal/visual-spatial tasks were unimpaired. After accounting for non-cognitive factors, group differences diminished in verbal learning, whereas differences in the other domains remained significant. Against our hypotheses, the present findings indicate that some cognitive deficits in PSY cannot be attributed to momentary confounding factors.

How a pilot's brain copes with stress and mental load? Insights from the executive control network

In aviation, mental workload and stress are two major factors that can considerably impact a pilot's flight performance and decisions. Their consequences can be even more dramatic in single-pilot aircraft or with the forthcoming single-pilot operations where the pilot will fly alone and will not be able to be assisted in case of difficulty. An accurate and automatic monitoring of the pilot's mental state could help to prevent the potentially dangerous effects of an excess mental workload and stress. For example, some tasks could be allocated to automation or to a ground-based flight crew if a mental overload or significant stress is detected. In the current study, the brain activity of 20 private pilots was recorded with a fNIRS device during two realistic flight simulator scenarios. The mental workload was manipulated with the added difficulty of a secondary task and stress was induced by a social stressor. Our results confirmed the sensitivity of the fNIRS readings to variations in the mental workload, with increased HbO2 concentration in regions of the executive control network (ECN), in particular in the dorsolateral prefrontal cortex and in lateral parietal regions, when the difficulty of the secondary task was high. The social stressor also triggered an HbO2 increase in the ECN, especially when it was combined with high mental workload. This latter result suggests that mental workload and stress together can have cumulative effects, and coping with both factors is possible at the expense of an extra recruitment of the ECN. Finally, results also revealed a time-on-task effect, with a progressive reduction of the HbO2 signal in the ECN during the flight scenario, suggesting that these regions are sensitive to short term habituation to the tasks. Overall, fNIRS efficiently indexed mental load, stress, and practice effects.

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.

Functional MRI Techniques Suggesting that the Stress System Interacts with Three Large Scale Core Brain Networks to Help Coordinate the Adaptive Response: A Systematic Review

OBJECTIVE

Synthesis of functional MRI (fMRI) and functional connectivity (FC) analysis data on human stress system (SS) function, as it relates to the dynamic function of the Salience (SN), Default Mode (DMN) and Central Executive (CEN) networks.

METHODS

Systematic search of Medline, Scopus, Clinical Trials.gov, and Google Scholar databases of studies published prior to September 2022 resulted in 28 full-text articles included for qualitative synthesis.

RESULTS

Acute stress changes the states of intra-/inter- neural network FCs and activities from those of resting, low arousal state in the SN, DMN and CEN, during which intra- and inter-network FCs and activities of all three networks are low. SS activation is positively linked to the activity of the SN and negatively to that of the DMN, while, in parallel, it is associated with an initial decrease and a subsequent increase of the intra- network FC and activity of the CEN. The FC between the DMN and the CEN increases, while those between the SN and the CEN decrease, allowing time for frontal lobe strategy input and "proper" CEN activity and task decision. SN activation is linked to sensory hypersensitivity, "impaired" memory, and a switch from serial to parallel processing, while trait mindfulness is associated with FC changes promoting CEN activity and producing a "task-ready state".

CONCLUSION

SS activation is tightly connected to that of the SN, with stress hormones likely potentiating the intra-network FC of the latter, attenuating that of the DMN, and causing a biphasic suppression- to-activation response of the CEN, all adaptive changes favoring proper decisions and survival.

Modeling Brain Dynamics During Virtual Reality-Based Emergency Response Learning Under Stress

BACKGROUND

Stress affects learning during training, and virtual reality (VR) based training systems that manipulate stress can improve retention and retrieval performance for firefighters. Brain imaging using functional Near Infrared Spectroscopy (fNIRS) can facilitate development of VR-based adaptive training systems that can continuously assess the trainee's states of learning and cognition.

OBJECTIVE

The aim of this study was to model the neural dynamics associated with learning and retrieval under stress in a VR-based emergency response training exercise.

METHODS

Forty firefighters underwent an emergency shutdown training in VR and were randomly assigned to either a control or a stress group. The stress group experienced stressors including smoke, fire, and explosions during the familiarization and training phase. Both groups underwent a stress memory retrieval and no-stress memory retrieval condition. Participant's performance scores, fNIRS-based neural activity, and functional connectivity between the prefrontal cortex (PFC) and motor regions were obtained for the training and retrieval phases.

RESULTS

The performance scores indicate that the rate of learning was slower in the stress group compared to the control group, but both groups performed similarly during each retrieval condition. Compared to the control group, the stress group exhibited suppressed PFC activation. However, they showed stronger connectivity within the PFC regions during the training and between PFC and motor regions during the retrieval phases.

DISCUSSION

While stress impaired performance during training, adoption of stress-adaptive neural strategies (i.e., stronger brain connectivity) were associated with comparable performance between the stress and the control groups during the retrieval phase.

Ethyl pyruvate prevents long-term stress-induced cognitive decline and modulates Akt/GSK-3β signaling

Stress is an inevitable part of life and, simultaneously, a stimulus that can trigger various neuropsychiatric disorders. Therefore, proper stress management is essential for maintaining a healthy life. In this study, we investigated the suppression of stress-induced cognitive deficit by controlling changes in synaptic plasticity caused by stress and confirmed that ethyl pyruvate (EP) has such an effect. Corticosterone, a stress hormone, suppresses long-term potentiation (LTP) in mouse acute hippocampal slices. EP blocked the LTP inhibitory effect of corticosterone by regulating GSK-3β function. Restraint stress for 2 weeks increased the anxiety levels and caused the cognitive decline in the experimental animals. Administration of EP for 14 days did not affect the increase in anxiety caused by stress but improved cognitive decline caused by stress. In addition, the decrease in neurogenesis and synaptic function deficits in the hippocampus, which cause of cognitive decline due to stress, were improved by EP administration. These effects appear via regulation of Akt/GSK-3β signaling, as in in vitro studies. These results suggest that EP prevents stress-induced cognitive decline through the modulation of Akt/GSK-3β-mediated synaptic regulation.

It is not always positive: emotional bias in young and older adults

Healthy ageing has been associated with a bias toward positive information and greater psychological well-being. However, to what extent this positivity bias also applies to prioritizing positive information under emotional competition is unclear. Old and young adults performed a word-face interference task, in which they responded to the valence of positive and negative target-words while ignoring happy or angry distractor-faces that could be affectively congruent or incongruent. A control condition with scrambled neutral distractor-faces was also used. Findings showed small facilitation effects with faster responses when targets and distractors were affectively congruent and large interference effects with slower responses when targets and distractors were affectively incongruent compared to the control condition. Importantly, whereas for younger adults there was a similar pattern of interference from happy and angry distractor-faces, for older adults there was greater interference from angry distractor-faces. The present findings are discussed in the context of emotional bias literature.

Nx4 attenuated stress-induced activity of the anterior cingulate cortex-A post-hoc analysis of a randomized placebo-controlled crossover trial

OBJECTIVE

Stress-related symptoms are associated with significant health and economic burden. Several studies suggest Nx4 for the pharmacological management of the stress response and investigated the underlying neural processes. Here we hypothesized that Nx4 can directly affect the stress response in a predefined stress network, including the anterior cingulate cortex (ACC), which is linked to various stress-related symptoms in patients.

METHODS

In a randomized, placebo-controlled, double-blind, crossover trial, 39 healthy males took a single dose of placebo or Nx4. Psychosocial stress was induced by the ScanSTRESS paradigm inside an MRI scanner, and stress network activation was analyzed in brain regions defined a priori.

RESULTS

Using the placebo data only, we could validate the activation of a distinct neural stress pattern by the ScanSTRESS paradigm. For Nx4, we provide evidence of an attenuating effect on this stress response. A statistically significant reduction in differential stress-induced activation in the right supracallosal ACC was observed for the rotation stress task of the ScanSTRESS paradigm. The results add to previously published results of Nx4 effects on emotion regulation.

CONCLUSIONS

Our results strengthen the hypothesis that Nx4 modulates the stress response by reducing the activation in parts of the neural stress network, particularly in the ACC.

TRIAL REGISTRATION

NCT02602275; ClinicalTrials.gov.

The effect of perceived stress on cognition is mediated by personality and the underlying neural mechanism

Perceived stress impairs cognitive function across the adult lifespan, but the extent to which cognition decline is variable across individuals. Individual differences in the stress response are described as personality traits. Substantial individual differences in the magnitude of cognitive impairment that is induced by short-term perceived stress are poorly understood. The present study tested the hypothesis that the relationship between short-term perceived stress and different aspects of cognition is mediated by personality traits. The study included 1066 participants with behavior and neuroimaging data from the Human Connectome Project after excluding individuals with missing variables. In the result, the parallel multiple mediation model demonstrated that the influence of perceived stress on the total and crystalized cognition is mainly mediated by neuroticism (indirect effect = -0.04, p < 0.05) and conscientiousness (indirect effect = 0.05, p < 0.05) in adults. Cortical thickness value (n = 1066) of the right superior frontal gyrus (SFG) showed not only positive correlations with short-term perceived stress and neuroticism, but negative associations with cognition. The chain mediation model found that the right SFG and neuroticism play a small but significant chain mediating effect between stress and total cognition. The strength of the resting-state functional connectivity (n = 968) between the left orbitofrontal cortex versus the left superior medial frontal cortex was positively correlated with crystallized cognition and negatively associated with conscientiousness. These results extend previous findings by the impacts of short-term perceived stress on cognitive function is mediated by neuroticism and the right SFG was the underlying neural mechanism.

Effects of a Multi-Suckling System Combined With Enriched Housing Post-Weaning on Response and Cognitive Resilience to Isolation

Improving welfare is still a critical issue in pig husbandry. Upgrades of the housing environment seem to be a promising solution to optimise resilience as a whole, and therefore improve animal welfare. The objective of this study was to evaluate the effect of an alternative housing system to enhance cognitive resilience and also to promote the pigs' welfare. A total of 96 piglets from two contrasted housing systems [alternative housing system (AHS) vs. conventional system (CONV)] was used. The major upgrades of the alternative system were multi-litter housing during lactation, delayed weaning, extra space allowance, and environmental enrichment from birth onwards. To estimate welfare, weight, and feed intake (as a general indicator of performances), the tear staining area (as a chronic stress indicator), behavioural postures, heart rate traits, and saliva cortisol concentration were measured over a 21 h-isolation. To assess cognitive resilience, the pigs were subjected to a maze with a social reward both before and after the isolation challenge and indicators of cognitive abilities were followed. The AHS pigs showed lower cortisol levels and tear staining area before the challenge, demonstrating overall better welfare due to the alternative housing conditions. During the challenge, AHS pigs had a lower heart rate, higher heart rate variability, and higher vagal activity than the CONV pigs, which might indicate a reduced sensitivity to the stressor. AHS pigs appeared to have a better long-term memory tested in a maze. Providing social and environmental enrichments, that fit the satisfaction of the essential needs of the pigs better, appears to be beneficial for pig welfare as a whole. Its effects on cognitive resilience still need to be proven.

Inter-relationships between changes in stress, mindfulness, and dynamic functional connectivity in response to a social stressor

We conducted a study to understand how dynamic functional brain connectivity contributes to the moderating effect of trait mindfulness on the stress response. 40 male participants provided subjective reports of stress, cortisol assays, and functional MRI before and after undergoing a social stressor. Self-reported trait mindfulness was also collected. Experiencing stress led to significant decreases in the prevalence of a connectivity state previously associated with mindfulness, but no changes in two connectivity states with prior links to arousal. Connectivity did not return to baseline 30 min after stress. Higher trait mindfulness was associated with attenuated affective and neuroendocrine stress response, and smaller decreases in the mindfulness-related connectivity state. In contrast, we found no association between affective response and functional connectivity. Taken together, these data allow us to construct a preliminary brain-behaviour model of how mindfulness dampens stress reactivity and demonstrate the utility of time-varying functional connectivity in understanding psychological state changes.

From Wellbeing to Social Media and Back: A Multi-Method Approach to Assessing the Bi-Directional Relationship Between Wellbeing and Social Media Use

Literature concerning the relationship between social media use and wellbeing is inconsistent in its findings, and most research has focused on time spent on social media rather than on what emerging adults do there, with whom and why. Here, we investigated whether momentary social stress affects emerging adults’ social media use, and whether this social media use relates to subsequent changes in wellbeing. We implemented a multi-method paradigm utilising objective and self-report data to investigate how social stress relates to how (much) and why emerging adults use social media. We report on findings based on 114 17–25-year-old emerging adults recruited on university campus. Our findings suggest that social stress does not affect adolescents’ subsequent social media use and that there is no relationship between social media use after stress and changes in momentary wellbeing. Our work illustrates the need for detailed approaches in social media and psychological wellbeing research.

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

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

The modulation of salience and central executive networks by acute stress in healthy males: An EEG microstates study

EEG microstate analysis involves the examination of topographies of the scalp potential fields to indicate the temporal dynamics of resting-state networks on a millisecond time scale, through which we can investigate the subsecond brain dynamics of stress in individuals. The present study implemented the EEG microstate method to explore the temporal dynamic changes of the large-scale brain networks induced by acute stress. The participants (n = 51) were randomly exposed to a stress condition (n = 25) (induced by Trier Social Stress Test, TSST) or a control condition (n = 26). Two 4-min blocks of resting EEG data were recorded before and after the stress/control test to reflect the stress effect on temporal dynamics of EEG microstates. The results showed that the stress group had larger occurrences and coverage of microstate class C during the post-test session than during the pre-test session. This pattern was reversed in the control group. Further, the microstate class C showed positive correlations with negative affect and perceived stress levels following acute stress. The transition probability between the microstates C and D was larger during the post-test session than during the pre-test session in the stress group, but not different in the control group. In addition, the microstate pairs C and D were positively correlated with negative affect and perceived stress levels. The proportion and sequence of EEG microstates class C and D reflected deviations of salience and executive functions following acute stress. We further proposed that the coordination between salience and executive functions was promoted by acute stress.

Neuroinflammation in cognitive decline post-cardiac surgery (the FOCUS study): an observational study protocol

INTRODUCTION

Postoperative cognitive dysfunction occurs frequently after coronary artery bypass grafting (CABG). The underlying mechanisms remain poorly understood, but neuroinflammation might play a pivotal role. We hypothesise that systemic inflammation induced by the surgical trauma could activate the innate immune (glial) cells of the brain. This could lead to an exaggerated neuroinflammatory cascade, resulting in neuronal dysfunction and loss of neuronal cells. Therefore, the aims of this study are to assess neuroinflammation in vivo presurgery and postsurgery in patients undergoing major cardiac surgery and investigate whether there is a relationship of neuroinflammation to cognitive outcomes, changes to brain structure and function, and systemic inflammation.

METHODS AND ANALYSIS

The FOCUS study is a prospective, single-centre observational study, including 30 patients undergoing elective on-pump CABG. Translocator protein (TSPO) positron emission tomography neuroimaging will be performed preoperatively and postoperatively using the second generation tracer ¹⁸F-DPA-714 to assess the neuroinflammatory response. In addition, a comprehensive cerebral MRI will be performed presurgery and postsurgery, in order to discover newly developed brain and vascular wall lesions. Up to 6 months postoperatively, serial extensive neurocognitive assessments will be performed and blood will be obtained to quantify systemic inflammatory responses and peripheral immune cell activation.

ETHICS AND DISSEMINATION

Patients do not benefit directly from engaging in the study, but imaging neuroinflammation is considered safe and no side effects are expected. The study protocol obtained ethical approval by the Medical Research Ethics Committee region Arnhem-Nijmegen. This work will be published in peer-reviewed international medical journals and presented at medical conferences.

TRIAL REGISTRATION NUMBER

NCT04520802.

Measuring inter-individual differences in stress sensitivity during MR-guided prostate biopsy

People often experience high level of distress during invasive interventions, which may exceed their coping abilities. This may be in particular evident when confronted with the suspicion of cancer. Taking the example of prostate biopsy sampling, we aimed at investigating the impact of an MRI guided prostate biopsy on the acute stress response and its mechanistic basis. We recruited 20 men with a clinical suspicion of prostate cancer. Immediately before an MRI guided biopsy procedure, we conducted fMRI in the same scanner to assess resting-state brain connectivity. Physiological and hormonal stress measures were taken during the procedure and associated with questionnaires, hair cortisol levels and brain measures to elucidate mechanistic factors for elevated stress. As expected, patients reported a stress-related change in affect. Decreased positive affect was associated with higher hair but not saliva cortisol concentration. Stronger use of maladaptive emotion regulation techniques, elevated depression scores and higher within-salience-network connectivity was associated with stronger increase in negative affect and/or decrease of positive affect during the procedure. While being limited in its generalization due to age, sample size and gender, our proof of concept study demonstrates the utility of real-life stressors and large-scale brain network measures in stress regulation research with potential impact in clinical practice.

Multivariate associative patterns between the gut microbiota and large-scale brain network connectivity

Research on the gut-brain axis has accelerated substantially over the course of the last years. Many reviews have outlined the important implications of understanding the relation of the gut microbiota with human brain function and behavior. One substantial drawback in integrating gut microbiome and brain data is the lack of integrative multivariate approaches that enable capturing variance in both modalities simultaneously. To address this issue, we applied a linked independent component analysis (LICA) to microbiota and brain connectivity data.We analyzed data from 58 healthy females (mean age =  21.5 years). Magnetic Resonance Imaging data were acquired using resting state functional imaging data. The assessment of gut microbial composition from feces was based on sequencing of the V4 16S rRNA gene region. We used the LICA model to simultaneously factorize the subjects' large-scale brain networks and microbiome relative abundance data into 10 independent components of spatial and abundance variation.LICA decomposition resulted in four components with non-marginal contribution of the microbiota data. The default mode network featured strongly in three components, whereas the two-lateralized fronto-parietal attention networks contributed to one component. The executive-control (with the default mode) network was associated to another component. We found that the abundance of Prevotella genus was associated with the strength of expression of all networks, whereas Bifidobacterium was associated with the default mode and frontoparietal-attention networks.We provide the first exploratory evidence for multivariate associative patterns between the gut microbiota and brain network connectivity in healthy humans considering the complexity of both systems.

Heart rate variability for determining autonomic nervous system effects of lifestyle behaviors in early life: A systematic review

BACKGROUND

An unhealthy lifestyle negatively alters autonomic nervous system (ANS) activity as reflected by decreased heart rate variability (HRV), increasing cardiovascular disease (CVD) risk. Research investigating the effect of modifiable lifestyle factors on ANS activity in young children is limited. Early identification of these risk factors is vital to improving long-term individual and public health outcomes. A systematic review was conducted to assess the effect of maternal or child modifiable lifestyle factors on child ANS activity.

METHODS

Following the 2009 PRISMA guidelines, three electronic databases were searched from February 2018 - July 2019 for articles describing human trials between 1996 - 2019. Included studies examined ANS activity of children between 28 weeks gestational age - 6 years in relation to modifiable lifestyle CVD risk factors.

RESULTS

Twenty-six studies fulfilled inclusion criteria. Sixteen studies reported that modifiable lifestyle factors significantly influenced the HRV of children. Increased HRV was significantly associated with higher maternal zinc and omega-3 fatty acid intake, regular maternal aerobic exercise and a non-smoking environment. Child diet and body composition demonstrated some support for an association between these modifiable lifestyle factors and child HRV.

CONCLUSION

There is cross-sectional evidence supporting an association between maternal lifestyle factors and child HRV. Evidence is less supportive of a relationship between child modifiable lifestyle factors and child HRV. Monitoring the effects of lifestyle interventions on the ANS via HRV measurements of both mother and child may identify child CVD risk.

Acute Stress Improves Concentration Performance

Abstract. Acute stress can have both detrimental and beneficial effects on cognitive processing, but effects on concentration performance remain unclear. Here, we investigate the effects of acute psychosocial stress on concentration performance and possible underlying physiological and psychological mechanisms. The study sample comprised 47 healthy male participants who were randomly assigned either to a psychosocial stress situation (Trier Social Stress Test) or a neutral control task. Concentration performance was assessed using the d2 Test of Attention before and 30 min after the stress or control task. Salivary cortisol and alpha-amylase were repeatedly measured before and up to 1 hr after stress. We repeatedly assessed state anxiety using the State-Trait Anxiety Inventory and anticipatory cognitive stress appraisal using the Primary Appraisal Secondary Appraisal questionnaire. The stress group showed a significantly stronger improvement of concentration performance compared to the control group ( p = .042). Concentration performance improvement was predicted by increased state anxiety ( p = .020) and lower cortisol (stress) changes ( p = .043). Neither changes in alpha-amylase nor cognitive stress appraisal did relate to concentration performance. Our results show improved concentration performance after acute psychosocial stress induction that was predicted by higher state anxiety increases and lower cortisol increases. This points to a potential modulating role of specific psycho-emotional and physiological factors with opposite effects.

Decrease in Attentional Performance After Repeated Bouts of High Intensity Exercise in Association-Football Referees and Assistant Referees

Referees and assistant referees are submitted to high physical stress during matches. Pressure to make decisions in front of large crowds is another potential stressor. These two stressors can impair attention executive control, depending on physical fitness and individual vulnerability or resilience to situational pressure. Error percentage for referees and assistants may reach around 14% during a soccer match. Although previous studies have suggested that soccer referees and assistants should take cognitive assessments, they are only required by Fédération Internationale de Football Association (FIFA) to demonstrate knowledge of the rules and pass annually in a fitness test (FIFA-Test). This study aimed to assess attention performance in referees and assistants before and after the mandatory FIFA-Test. It is hypothesized that the high physical demands associated with the pressure to pass the FIFA-Test would interfere with attention performance. The sample included 33 referees and 20 assistants. The Continuous Visual Attention Test (CVAT) consisted of a 15-min Go/No-go task. Performance in the CVAT is based on four variables: omission and commission errors, reaction time, and variability of reaction time (VRT). Failure in the CVAT was defined by a performance below the 5th percentile of the age- and sex-matched normative data in at least one variable of the CVAT. Before the FIFA-Test all participants performed the CVAT. The second CVAT began 3-7 min directly following completion of the FIFA-test. Considering only the officials who passed both the FIFA-Test and the first CVAT (19 referees and 15 assistants), 44% (9 referees and 6 assistants) exhibited a performance decline in the second CVAT. A significant increase in VRT was found after the high intensity exercise. As increase in VRT is thought to reflect executive dysfunctions and lapses of attention, we concluded that physical fitness alone may not be enough to help officials cope with the physical and contextual stresses associated with the FIFA-Test. These data suggest that over 35% of soccer referees and their assistants who were considered physically able to referee matches may not be mentally prepared for the attentional demands of refereeing soccer matches.

Melatonin receptor agonist Piper betle L. ameliorates dexamethasone-induced early life stress in adult zebrafish

Early life exposure to stress has been suggested to be a crucial factor for the development of the brain and its functions. It is well documented that childhood stress is a risk factor for sleep problems in adulthood. Piper betle L. leaf extract (PB) has been used in several traditional medicines to cure various ailments. Recently, PB has been proved to have antidepressant activity. The literature suggests that antidepressants affect the synthesis and release of melatonin through several mechanisms. Thus, this study investigated the potential role of PB for the treatment of sleep disruption after early life stress exposure. Firstly, dexamethasone (DEX) (2 and 20 mg/l for 24 h) was administered to zebrafish larvae on the 4th day post-fertilization (dpf) to induce early life stress. The effects of stress on behaviour during adulthood, melatonin level and stress-related gene expression (nfkb) in the brain were then studied. Next, the possible role of PB (10 and 30 mg/Kg) was studied by measuring its effect on behaviour and by quantifying the expression levels of several melatonin-related (MT1, MT2, aanat1, aanat2) and stress-related (nfkb) genes by qPCR. DEX-treated zebrafish exhibited anxious behaviour, along with a lower level of melatonin and a higher mRNA expression of nfkb. After treatment with PB, a similar effect on behaviour and gene expression levels as the melatonin treatment group (10 mg/kg; positive control) was seen in adult zebrafish. These molecular confirmations of the observed behavioural effects of the PB indicate a possible role in the treatment of early life stress-induced sleep disruption.

Acute stress enhances general-knowledge semantic memory

Acute psychological stress consistently impairs episodic memory, which consists of memory for events that are associated with a specific context. However, researchers have not yet established how stress influences semantic memory, which consists of general knowledge that is devoid of context. In the present study, participants either underwent stress induction or a control task prior to taking a trivia test that was designed to measure semantic memory. In contrast to the wealth of prior research on episodic memory, we found that stress enhanced semantic-memory retrieval. Supporting this finding, higher cortisol reactivity to stress was associated with better performance on the trivia test. Together with the results from previous studies of episodic memory, our findings suggest that stress differentially influences memory retrieval, depending on the degree to which the retrieval of a given memory relies on medial-temporal, neocortical, and striatal brain regions.

I'm going to fail! Acute cognitive performance anxiety increases threat-interference and impairs WM performance

Stress can impair cognitive performance, as commonly observed in cognitive performance anxiety (CPA; e.g., test anxiety). Cognitive theories indicate that stress impairs performance by increasing attention to negative thoughts, a phenomenon also known as threat-interference. These theories are mainly supported by findings related to self-report measures of threat-interference or trait anxiety. Our main aim was to test, for the first time in a single study, the hypotheses that acute CPA-related stress negatively affects both working memory (WM) performance and objectively assessed threat-interference during performance. In addition, we aimed to assess the validity of a new stress-induction procedure that was developed to induce acute CPA. Eighty-six females were randomly assigned to a CPA-related stress group (n = 45) or a control group. WM performance and threat-interference were assessed with an n-back task (2-back and 3-back memory loads), using CPA-related words as distracters. The stress group showed higher state anxiety and slower WM performance. Both effects were moderated by trait CPA: the effects were stronger for individuals with higher trait CPA. Finally, trait CPA moderated the effect of stress on threat-interference during higher cognitive load: individuals with higher trait CPA in the stress group showed higher threat-interference. We conclude that acute CPA increases threat-interference and impairs WM performance, especially in vulnerable individuals. The role of threat-interference, cognitive load, and trait anxiety should be taken into account in future research. Finally, our method (combining our stressor and modified n-back task) is effective for studying stress-cognition interactions in CPA.

Impaired Executive Functioning of Sexual Assault Survivors with Acute Stress Disorder

This study aimed to examine the executive functioning of survivors exposed to recent sexual assaults. Twenty-seven female rape survivors who met the criterion for acute stress disorder (ASD) were enrolled and completed the assessment within 4 weeks after the traumatic experience. Additionally, 25 age-matched female health controls (HC) never exposed to such a traumatic event were enrolled. The assessments evaluated psychiatric symptoms including post-traumatic stress symptoms, depression, anxiety, and trait and state anger; general intelligence indexed by intellectual quotient (IQ); and executive functioning including set-shift/attention, planning, spatial working memory, and inhibition using the Cambridge Neuropsychological Test Automated Battery. The ASD group showed higher levels of depression, anxiety, and state anger, and lower IQ than the HC group. The ASD group also showed global impairment of executive functioning for set-shifting, attention, planning, and response inhibition compared to the HC group. Rather than being associated with low IQ and education levels, these results could be from trauma-related effects in survivors with ASD. Additionally, the state anger level was related to survivors’ deficient executive functioning. The findings indicate the importance of providing assessment and intervention efforts to sexual assault survivors soon after the trauma occurs.

Altered reward learning and hippocampal connectivity following psychosocial stress

Acute stress has a profound influence on learning, as has been demonstrated in verbal learning or fear conditioning. However, its effect on appetitive conditioning is still unclear. Fear conditioning research suggests the possibility of overgeneralization of conditioning to the CS- under acute stress due to its effect on prefrontal and hippocampal processing. In this study, participants (N = 56 males) were subjected to the Trier Social Stress Test or a placebo version. After that, all participants underwent an appetitive conditioning paradigm in the fMRI, in which one neutral cue (CS+) was repeatedly paired with reward, while another (CS-) was not. Importantly, the stress-group revealed overgeneralization of conditioning to the CS- on the behavioral level. On the neural level, stressed participants showed increased connectivity between the hippocampus and amygdala, vACC, and OFC, which maintain specificity of conditioning and also showed reduced differential activation. The results indicate overgeneralization of appetitive conditioning promoted by maladaptive balancing of pattern separation and pattern completion in the hippocampus under acute stress and are discussed with respect to clinical implications.

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

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