The effects of acute stress on core executive functions: A meta-analysis and comparison with cortisol

Acute and past subjective stress influence working memory and related neural substrates

Stress has been proposed to affect cognitive control capacities, including working memory (WM) maintenance. This effect may depend on variability in stress reactivity and past subjective stress. However, as most studies employed between-subjects designs, evidence for within-subject stress effects remains scarce. To understand the role of intra-individual stress effects on WM, we adopted a within-subject design to study how acute stress, variability in stress reactivity, and past subjective stress influence behavioral and neural WM mechanisms. Thirty-four healthy males performed a WM task during functional magnetic resonance imaging (fMRI) in a control versus acute stress condition following the Trier Social Stress Test, a validated psychosocial stressor method. We tested for stress effects on WM performance and related neural activation by associating them with individual acute stress responsivity and past subjective stress experience using retrospective self-report questionnaires. We found no evidence of an effect of acute stress or related stress-reactivity on intra-individual WM performance. However, past subjective stress negatively influenced acute stress-induced changes to WM. On the neural level, acute stress reduced WM-related activation in the dorsolateral prefrontal cortex (dlPFC). The observed negative influence of inter-individual variability in past subjective stress experience on changes in WM performance, suggests that past subjective stress might induce vulnerability for impairing effects of acute stress on cognitive functioning. Because acute stress reduced WM-related dlPFC activation while WM performance remained unaffected, acute stress might boost neural processing efficiency in this group of high performing healthy individuals. Our study suggests that measures of past subjective stress should be considered when studying and interpreting the effects of acute stress on cognition.

Neurocognitive mechanisms of emotion-related impulsivity: The role of arousal

Prior research suggests that a traitlike tendency to experience impulsivity during states of high emotion is robustly associated with many forms of psychopathology. Several studies tie emotion-related impulsivity to response inhibition deficits, but these studies have not focused on the role of emotion or arousal within subjects. The present study tested whether arousal, measured by pupil dilation, amplifies deficits in response inhibition for those high in emotion-related impulsivity. Participants (N = 85) completed a measure of emotion-related impulsivity, underwent a positive mood induction procedure that reduced heterogeneity in mood states, and completed a response inhibition task. Pupil dilation was used to index arousal during the response inhibition task. Generalized linear mixed effect modeling yielded the hypothesized interaction between arousal (pupil dilation) and emotion-related impulsivity in predicting response inhibition performance at the trial level. Emotion-related impulsivity relates to more difficulties with response inhibition during moments of high arousal.

Women with high estradiol status are protected against declarative memory impairment by pre-learning stress

Stress is a potent modulator of learning and memory. Factors contributing to whether stress aids or impairs memory are timing of the stressor, memory stage, form of memory studied, and sex of the subjects. The female sex hormone 17-beta-estradiol (E2) has widespread effects in the brain and affects hippocampus-dependent memory in animals. In humans, the interaction between stress effects and E2 has not been widely studied. We report data from a healthy sample divided into 3 hormone-status groups: free-cycling women in the early follicular phase (EF: low E2, low progesterone [P4]), or during midcycle (MC: high E2, low P4), and men. Participants within each hormone-status group were randomly assigned to a psychosocial stressor or a control treatment 37 min before encoding a short story of neutral content. We found a Hormone status × Stress × Time (immediate, 35-min, 24-h delayed recall) interaction. Irrespective of time, hormone status mattered only after stress treatment: stressed early follicular women had poorer recall compared to stressed men and midcycle women. Only in the early follicular group, recall was negatively correlated with increases in salivary cortisol, but not with blood levels of E2 and P4. To uncover changes beyond immediate recall, we computed the individual percent change relative to immediate recall and repeated the analysis for these adjusted 35-min and 24-h data. Despite the lack of a stress effect in raw data, memory in stressed men was more stable over time (35-min and 24-h delay) than in unstressed men. In contrast, stressed EF-women (vs. control) recalled less at the 35-min and (as a trend) at the 24-h delay. Stressed MC-women (vs. control) showed less recall only at the 35-min delay while compensating this stress effect after a 24-h consolidation interval. Overall, results suggest that women in high-E2 midcycle phase could be less vulnerable to effects of pre-learning stress on declarative memory encoding and consolidation.

Neurocognitive, emotional and neuroendocrine correlates of exposure to sexual assault in women

BACKGROUND

Survivors of sexual assault are vulnerable to long-term negative psychological and physical health outcomes, but few studies have investigated changes in cognition, emotional processing and brain function in the early stages after sexual assault. We used a multimodal approach to identify the cognitive and emotional correlates associated with sexual assault in women.

METHODS

Twenty-seven female survivors of sexual assault were included within 4 weeks of the traumatic event, and they were compared with 20 age-matched controls. Participants underwent functional MRI while performing cognitive/emotional tasks (n-back, emotional go/no-go, mental imagery). We also measured diurnal salivary cortisol and conducted neuropsychological assessments of attention and memory abilities.

RESULTS

Relative to the control group, the survivors group had lower levels of morning cortisol and showed attentional deficits. We observed no between-group differences in brain activation during the n-back or mental imagery tasks. During the emotional go/no-go task, however, the survivors group showed a lack of deactivation in the dorsal anterior cingulate cortex when processing emotional material, relative to neutral material. Exploratory analyses in the survivors group indicated that symptom severity was negatively associated with cerebellar activation when positive emotional (happy) content interfered with response inhibition, and positively associated with cerebellar activation when thinking of positive (happy) memories.

LIMITATIONS

The small sample size was the main limitation of this study.

CONCLUSION

Dysfunctions in the dorsal anterior cingulate cortex and the cerebellum may represent early functional brain modifications that alter higher cognitive processes when emotional material is involved.

Reappraisal inventiveness: impact of appropriate brain activation during efforts to generate alternative appraisals on the perception of chronic stress in women

BACKGROUND AND OBJECTIVES

Previous research indicated that more left-lateralized prefrontal activation during cognitive reappraisal efforts was linked to a greater capacity for generating reappraisals, which is a prerequisite for the effective implementation of cognitive reappraisal in everyday life. The present study examined whether the supposedly appropriate brain activation is relevant in terms of more distal outcomes, i.e., chronic stress perception.

DESIGN AND METHODS

Prefrontal EEG alpha asymmetry was recorded while female participants were generating reappraisals for stressful events and was correlated with their self-reported chronic stress levels in everyday life (n = 80).

RESULTS

Women showing less left-lateralized brain activity in the ventrolateral prefrontal cortex during cognitive reappraisal efforts reported experiencing more stress in their daily lives. This effect was independent of self-efficacy beliefs in managing negative emotions.

CONCLUSION

These findings underline the practical relevance of individual differences in appropriate brain activation during emotion regulation efforts and the assumedly related basic capacity for the generation of cognitive reappraisals to the feeling of being stressed. Implications include the selection of interventions for the improvement of coping with stress in women in whom the capability for appropriate brain activation during reappraisal efforts may be impaired, e.g., due to depression or old age.

Prefrontal cortex modulates the correlations between brain-derived neurotrophic factor level, serotonin, and the autonomic nervous system

Top-down regulation in the human brain and anatomical connections between the prefrontal cortex (PFC) and specific catecholamine-related regions have been well-studied. However, the way in which the PFC modulates downstream neuro-networks in terms of serotonin and the autonomic nervous system (ANS) by variation in the level of brain-derived neurotrophic factor (BDNF) is still unclear. We recruited sixty-seven healthy subjects. Serotonin transporter (SERT) availability was examined by SPECT with [¹²³I]ADAM analysis; heart rate variability (HRV) testing was performed, and the BDNF level was measured. The Wisconsin card-sorting test (WCST), which assesses PFC activation, was also conducted. The interactions of BDNF level and SERT availability were significant in relation to the HRV indexes of low frequency, high frequency, total power, and mean heart rate range. Moderate to significant positive correlations between SERT availability and the above-mentioned HRV indexes existed only in subjects with a low BDNF level. Furthermore, in the low BDNF level group, only those with high WCST perseveration errors or low category completions exhibited significant positive correlations between SERT availability and HRV indexes. A lower BDNF level and poorer PFC function might modulate the synergistic effects of serotonergic and ANS systems in order to maintain brain physiological and psychological homeostasis.

Induced Positive Mood and Cognitive Flexibility: Evidence from Task Switching and Reversal Learning

Positive mood often facilitates cognitive functions. Facilitation is hypothesized to be due to an increase in dopamine occurring in positive mood states. However, facilitation has not been consistently found in studies of cognitive flexibility. This inconsistent relationship may reflect the numerous ways cognitive flexibility is measured. Moreover, there is evidence that the role of dopamine in cognitive flexibility performance depends on the type of measure used. In the current study, we employed a probabilistic two-card reversal learning task (n = 129) and a Stroop-like task switching procedure (n = 188) in a college student population. We used a standardized set of mood videos to induce a positive, negative, or neutral mood state. Negative mood states were included to account for possible effects of arousal on performance, which is seen in both positive and negative mood inductions. Based on current theories of positive mood and cognition, we hypothesized that there would be differences in the effects of a positive mood induction on cognitive flexibility as assessed by task switching and reversal learning tasks. The mood induction successfully induced high levels of amusement and increased valence in the positive mood group and high levels of repulsion and decreased valence in the negative mood group. However, there were no differences in cognitive flexibility across any of the mood groups, as assessed by switch costs in task switching and correct choices after the reversal in reversal learning. Overall, these findings do not support the hypothesis that positive mood improves cognitive flexibility.

The role of genetic variation in the glucocorticoid receptor (NR3C1) and mineralocorticoid receptor (NR3C2) in the association between cortisol response and cognition under acute stress

Although HPA - axis reactivity has repeatedly been related to cognitive functioning, ambiguity remains regarding the direction of the effect, i.e. whether it benefits or impairs functioning. Genetic factors that contribute to HPA - axis reactivity on the one hand and to cognitive functioning on the other could therefore help clarify the association between stress and cognition. We genotyped 10 single nucleotide polymorphisms (SNPs) on the NR3C1 gene (rs10482682, rs33389, rs10482633, rs10515522, rs2963156, rs4128428, rs9324918, rs41423247, rs6189, rs10052957) coding for the glucocorticoid receptor (GR) and 4 SNPs on the NR3C2 gene (rs6810951, rs4635799, rs11099695, rs2070950) coding for the mineralocorticoid receptor (MR) and required N=126 healthy males to perform tasks assessing attention and reasoning before and after experiencing an acute laboratory stressor (the Socially Evaluated Cold Pressor Test, SECPT). Haplotype analyses revealed significant effects of NR3C1 (p=0.011) and NR3C2 (p=0.034) on cortisol stress response. NR3C2 also influenced attentional performance via an interaction with stress-induced cortisol response (p<0.001). Neither NR3C1 haplotype nor NR3C2 haplotype was associated with reasoning abilities. Results suggest that the association between stress induced cortisol reactivity and cognition strongly depends on genetic variation. The idea of an optimal arousal level depending on stress reactivity and genetic disposition is discussed.

Acute stress affects prospective memory functions via associative memory processes

Recent findings suggest that acute stress can improve the execution of delayed intentions (prospective memory, PM). However, it is unclear whether this improvement can be explained by altered executive control processes or by altered associative memory functioning. To investigate this issue, we used physical-psychosocial stressors to induce acute stress in laboratory settings. Then participants completed event- and time-based PM tasks requiring the different contribution of control processes and a control task (letter fluency) frequently used to measure executive functions. According to our results, acute stress had no impact on ongoing task performance, time-based PM, and verbal fluency, whereas it enhanced event-based PM as measured by response speed for the prospective cues. Our findings indicate that, here, acute stress did not affect executive control processes. We suggest that stress affected event-based PM via associative memory processes.

Altered attentional control strategies but spared executive functioning in chronic cannabis users

BACKGROUND

Cannabis use has increased rapidly in recent decades. The increase in cannabis use makes it important to understand the potential influence of chronic use on attentional control and other executive functions (EFs). Because cannabis is often used to reduce stress, and because stress can constrain attentional control and EFs, the primary goal of this study was to determine the joint effect of acute stress and chronic cannabis use on specific EFs.

METHODS

Thirty-nine cannabis users and 40 non-users were assigned to either a stress or no stress version of the Maastricht Acute Stress Test. Participants then completed two cognitive tasks that involve EFs: (1) task switching, and (2) a novel Flexible Attentional Control Task. These two tasks provided assessments of vigilant attention, inhibitory control, top-down attentional control, and cognitive flexibility. Salivary cortisol was assessed throughout the study.

RESULTS

Reaction time indices showed an interaction between stress and cannabis use on top-down attentional control (p=0.036, n_p²=0.059). Follow-up tests showed that cannabis users relied less on top-down attentional control than did non-users in the no stress version. Despite not relying on top-down control, the cannabis users showed no overall performance deficits on the tasks.

CONCLUSIONS

Chronic cannabis users performed cognitive tasks involving EFs as well as non-users while not employing cognitive control processes that are typical for such tasks. These results indicate alterations in cognitive processing in cannabis users, but such alterations do not necessarily lead to global performance deficits.

Conceptual precision is key in acute stress research: A commentary on Shields, Sazma, & Yonelinas, 2016

A recent meta-analytic review by Shields, Sazma, & Yonelinas (2016) brings to the fore several conceptual issues within the stress and executive function (EF) literatures. We present a critique of these issues, using the review as an exemplar of how stress and EF are often examined empirically. The review summarizes research suggesting that EF is not only trait-like, but can be also state-like, influenced by factors such as acute stress. It has numerous strengths including its scope in examining EF across domains, inclusion of moderators, and timeliness, given the rapidly expanding field of stress research. We argue that the conclusions would be less equivocal with a more precise and neurally-informed consideration of EF, stressor, and timing assessments. A detailed discussion of these issues is provided, using the inhibition EF domain as an example, in order to illustrate key limitations and potential consequences of broad inclusion criteria. We endeavor to promote precise, shared definitions in the service of delineating a more complete and consistent account of acute stress effects on EF.

Lost in Time and Space: States of High Arousal Disrupt Implicit Acquisition of Spatial and Sequential Context Information

Biased cognition during high arousal states is a relevant phenomenon in a variety of topics: from the development of post-traumatic stress disorders or stress-triggered addictive behaviors to forensic considerations regarding crimes of passion. Recent evidence indicates that arousal modulates the engagement of a hippocampus-based "cognitive" system in favor of a striatum-based "habit" system in learning and memory, promoting a switch from flexible, contextualized to more rigid, reflexive responses. Existing findings appear inconsistent, therefore it is unclear whether and which type of context processing is disrupted by enhanced arousal. In this behavioral study, we investigated such arousal-triggered cognitive-state shifts in human subjects. We validated an arousal induction procedure (three experimental conditions: violent scene, erotic scene, neutral control scene) using pupillometry (Preliminary Experiment, n = 13) and randomly administered this method to healthy young adults to examine whether high arousal states affect performance in two core domains of contextual processing, the acquisition of spatial (spatial discrimination paradigm; Experiment 1, n = 66) and sequence information (learned irrelevance paradigm; Experiment 2, n = 84). In both paradigms, spatial location and sequences were encoded incidentally and both displacements when retrieving spatial position as well as the predictability of the target by a cue in sequence learning changed stepwise. Results showed that both implicit spatial and sequence learning were disrupted during high arousal states, regardless of valence. Compared to the control group, participants in the arousal conditions showed impaired discrimination of spatial positions and abolished learning of associative sequences. Furthermore, Bayesian analyses revealed evidence against the null models. In line with recent models of stress effects on cognition, both experiments provide evidence for decreased engagement of flexible, cognitive systems supporting encoding of context information in active cognition during acute arousal, promoting reduced sensitivity for contextual details. We argue that arousal fosters cognitive adaptation towards less demanding, more present-oriented information processing, which prioritizes a current behavioral response set at the cost of contextual cues. This transient state of behavioral perseverance might reduce reliance on context information in unpredictable environments and thus represent an adaptive response in certain situations.

Recent life stress exposure is associated with poorer long-term memory, working memory, and self-reported memory

Although substantial research has examined the effects of stress on cognition, much of this research has focused on acute stress (e.g. manipulated in the laboratory) or chronic stress (e.g. persistent interpersonal or financial difficulties). In contrast, the effects of recent life stress on cognition have been relatively understudied. To address this issue, we examined how recent life stress is associated with long-term, working memory, and self-reported memory in a sample of 142 healthy young adults who were assessed at two time points over a two-week period. Recent life stress was measured using the newly-developed Stress and Adversity Inventory for Daily Stress (Daily STRAIN), which assesses the frequency of relatively common stressful life events and difficulties over the preceding two weeks. To assess memory performance, participants completed both long-term and working memory tasks. Participants also provided self-reports of memory problems. As hypothesized, greater recent life stress exposure was associated with worse performance on measures of long-term and working memory, as well as more self-reported memory problems. These associations were largely robust while controlling for possible confounds, including participants' age, sex, and negative affect. The findings indicate that recent life stress exposure is broadly associated with worse memory. Future studies should thus consider assessing recent life stress as a potential predictor, moderator, or covariate of memory performance.

Brief Report: Low-Dose Hydrocortisone Has Acute Enhancing Effects on Verbal Learning in HIV-Infected Men

OBJECTIVE

Glucocorticoids are released in response to stress and alter cognition and brain function through both rapid nongenomic and slow genomic mechanisms. Administration of glucocorticoids in the form of hydrocortisone enhances aspects of learning and memory in individuals with PTSD but impairs these abilities in healthy individuals. We examine the time-dependent effects of glucocorticoids on cognition in HIV-infected men.

METHODS

In a double-blind placebo-controlled crossover study, we examined the time-dependent effects of a single low dose of hydrocortisone [10 mg; low-dose hydrocortisone (LDH)] on cognition in 45 HIV-infected men. Participants were randomized to receive either LDH or placebo and one month later, were given the opposite treatment. At each intervention session, cognition was assessed 30 minutes (assessing nongenomic effects) and 4 hours (assessing genomic effects) after pill administration. Self-reported stress/anxiety and cortisol/cytokines in saliva were measured throughout each session.

RESULTS

Compared with placebo, LDH doubled salivary cortisol levels. Cortisol returned to baseline 4 hours postadministration. At the 30-minute assessment, LDH enhanced verbal learning compared with placebo. Greater increases in cortisol were associated with greater enhancements in verbal learning. LDH did not affect subjective stress/anxiety or any other cognitive outcomes at the 30-minute or 4-hour time point.

CONCLUSIONS

The rapid effects of LDH on verbal learning suggests a nongenomic mechanism by which glucocorticoids can enhance cognition in HIV-infected men. The nonenduring nature of this enhancement may limit its clinical utility but provides insight into mechanisms underlying the effects of acute glucocorticoids on learning.

Effects of cortisol on the memory bias for emotional words? A study in patients with depression and healthy participants using the Directed Forgetting task

Mood congruent alterations in information processing such as an impaired memory bias for emotional information and impaired inhibitory functions are prominent features of a major depressive disorder (MDD). Furthermore, in MDD patients hypothalamic-pituitary-adrenal axis dysfunctions are frequently found. Impairing effects of stress or cortisol administration on memory retrieval as well as impairing stress effects on cognitive inhibition are well documented in healthy participants. In MDD patients, no effect of acute cortisol administration on memory retrieval was found. The current study investigated the effect of acute cortisol administration on memory bias in MDD patients (N = 55) and healthy controls (N = 63) using the Directed Forgetting (DF) task with positive, negative and neutral words in a placebo controlled, double blind design. After oral administration of 10 mg hydrocortisone/placebo, the item method of the DF task was conducted. Memory performance was tested with a free recall test. Cortisol was not found to have an effect on the results of the DF task. Interestingly, there was significant impact of valence: both groups showed the highest DF score for positive words and remembered significantly more positive words that were supposed to be remembered and significantly more negative words that were supposed to be forgotten. In general, healthy participants remembered more words than the depressed patients. Still, the depressed patients were able to inhibit intentionally irrelevant information at a comparable level as the healthy controls. These results demonstrate the importance to distinguish in experimental designs between different cognitive domains such as inhibition and memory in our study.

The effect of mild acute stress during memory consolidation on emotional recognition memory

Stress during consolidation improves recognition memory performance. Generally, this memory benefit is greater for emotionally arousing stimuli than neutral stimuli. The strength of the stressor also plays a role in memory performance, with memory performance improving up to a moderate level of stress and thereafter worsening. As our daily stressors are generally minimal in strength, we chose to induce mild acute stress to determine its effect on memory performance. In the current study, we investigated if mild acute stress during consolidation improves memory performance for emotionally arousing images. To investigate this, we had participants encode highly arousing negative, minimally arousing negative, and neutral images. We induced stress using the Montreal Imaging Stress Task (MIST) in half of the participants and a control task to the other half of the participants directly after encoding (i.e. during consolidation) and tested recognition 48h later. We found no difference in memory performance between the stress and control group. We found a graded pattern among confidence, with responders in the stress group having the least amount of confidence in their hits and controls having the most. Across groups, we found highly arousing negative images were better remembered than minimally arousing negative or neutral images. Although stress did not affect memory accuracy, responders, as defined by cortisol reactivity, were less confident in their decisions. Our results suggest that the daily stressors humans experience, regardless of their emotional affect, do not have adverse effects on memory.

Pregnancy-related anxiety and depressive symptoms are associated with visuospatial working memory errors during pregnancy

BACKGROUND

Cognitive deficits, especially in memory and concentration, are often reported during pregnancy. Similar cognitive dysfunctions can also occur in depression and anxiety. To date, few studies have investigated the associations between cognitive deficits and psychiatric symptoms during pregnancy. This field is of interest because maternal cognitive functioning, and particularly its higher-order aspects are related to maternal well-being and caregiving behavior, as well as later child development.

METHODS

Pregnant women (N =230), reporting low (n =87), moderate (n =97), or high (n =46) levels of depressive, general anxiety and/or pregnancy-related anxiety symptoms (assessed repeatedly with EPDS, SCL-90/anxiety subscale, PRAQ-R2, respectively) were tested in mid-pregnancy for their cognitive functions. A computerized neuropsychological test battery was used.

RESULTS

Pregnant women with high or moderate level of psychiatric symptoms had significantly more errors in visuospatial working memory/executive functioning task than mothers with low symptom level. Depressive symptoms throughout pregnancy and concurrent pregnancy-related anxiety symptoms were significant predictors of the performance in the task. General anxiety symptoms were not related to visuospatial working memory.

LIMITATIONS

Cognitive functions were evaluated only at one time-point during pregnancy precluding causal conclusions.

CONCLUSIONS

Maternal depressive symptoms and pregnancy-related anxiety symptoms were both associated with decrements in visuospatial working memory/executive functioning. Depressive symptoms seem to present more stable relationship with cognitive deficits, while pregnancy-related anxiety was associated only concurrently. Future studies could investigate, how stable these cognitive differences are, and whether they affect maternal ability to deal with demands of pregnancy and later parenting.

Lifetime Stress Exposure and Health: A Review of Contemporary Assessment Methods and Biological Mechanisms

Life stress is a central construct in health research because it is associated with increased risk for a variety of serious mental and physical health problems, including anxiety disorders, depression, cardiovascular disease, autoimmune disorders, Alzheimer's disease, certain cancers, and other diseases of aging. In this review, we examine how lifetime stress exposure contributes to elevated disease risk, and explore ongoing measurement and scientific issues related to this topic. To accomplish these goals, we first review existing instruments that have been developed for assessing perceived stress, self-reported life events, interviewer-assessed life stressors, and lifetime stress exposure. Next, we describe laboratory-based tasks that have been used for characterizing individual differences in psychological and biological stress reactivity. These methods have yielded an enormous amount of data showing how life stress influences the activity of the hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-gonadal axis, sympathetic-adrenal-medullary axis, and immune system, and how such processes can in turn cause allostatic load and biological embedding of the stress effect at the level of the human brain and genome. At the same time, many critical measurement and scientific issues remain unresolved, and we discuss these topics last while describing some pressing issues and opportunities for future research on stress and health.

Contribution of stress and sex hormones to memory encoding

Distinct stages of the menstrual cycle and the intake of oral contraceptives (OC) affect sex hormone levels, stress responses, and memory processes critically involved in the pathogenesis of mental disorders. To characterize the interaction of sex and stress hormones on memory encoding, 30 men, 30 women in the early follicular phase of the menstrual cycle (FO), 30 women in the luteal phase (LU), and 30 OC women were exposed to either a stress (socially evaluated cold-pressor test) or a control condition prior to memory encoding and immediate recall of neutral, positive, and negative words. On the next day, delayed free and cued recall was tested. Sex hormone levels verified distinct estradiol, progesterone, and testosterone levels between groups. Stress increased blood pressure, cortisol concentrations, and ratings of stress appraisal in all four groups as well as cued recall performance of negative words in men. Stress exposure in OC women led to a blunted cortisol response and rather enhanced cued recall of neutral words. Thus, pre-encoding stress facilitated emotional cued recall performance in men only, but not women with different sex hormone statuses pointing to the pivotal role of circulating sex hormones in modulation of learning and memory processes.

Inflammation, Self-Regulation, and Health: An Immunologic Model of Self-Regulatory Failure

Self-regulation is a fundamental human process that refers to multiple complex methods by which individuals pursue goals in the face of distractions. Whereas superior self-regulation predicts better academic achievement, relationship quality, financial and career success, and lifespan health, poor self-regulation increases a person's risk for negative outcomes in each of these domains and can ultimately presage early mortality. Given its centrality to understanding the human condition, a large body of research has examined cognitive, emotional, and behavioral aspects of self-regulation. In contrast, relatively little attention has been paid to specific biologic processes that may underlie self-regulation. We address this latter issue in the present review by examining the growing body of research showing that components of the immune system involved in inflammation can alter neural, cognitive, and motivational processes that lead to impaired self-regulation and poor health. Based on these findings, we propose an integrated, multilevel model that describes how inflammation may cause widespread biobehavioral alterations that promote self-regulatory failure. This immunologic model of self-regulatory failure has implications for understanding how biological and behavioral factors interact to influence self-regulation. The model also suggests new ways of reducing disease risk and enhancing human potential by targeting inflammatory processes that affect self-regulation.

Single-trial EEG-informed fMRI analysis of emotional decision problems in hot executive function

BACKGROUND

Executive function refers to conscious control in psychological process which relates to thinking and action. Emotional decision is a part of hot executive function and contains emotion and logic elements. As a kind of important social adaptation ability, more and more attention has been paid in recent years.

OBJECTIVE

Gambling task can be well performed in the study of emotional decision. As fMRI researches focused on gambling task show not completely consistent brain activation regions, this study adopted EEG-fMRI fusion technology to reveal brain neural activity related with feedback stimuli.

METHODS

In this study, an EEG-informed fMRI analysis was applied to process simultaneous EEG-fMRI data. First, relative power-spectrum analysis and K-means clustering method were performed separately to extract EEG-fMRI features. Then, Generalized linear models were structured using fMRI data and using different EEG features as regressors.

RESULTS

The results showed that in the win versus loss stimuli, the activated regions almost covered the caudate, the ventral striatum (VS), the orbital frontal cortex (OFC), and the cingulate. Wide activation areas associated with reward and punishment were revealed by the EEG-fMRI integration analysis than the conventional fMRI results, such as the posterior cingulate and the OFC. The VS and the medial prefrontal cortex (mPFC) were found when EEG power features were performed as regressors of GLM compared with results entering the amplitudes of feedback-related negativity (FRN) as regressors. Furthermore, the brain region activation intensity was the strongest when theta-band power was used as a regressor compared with the other two fusion results.

CONCLUSIONS

The EEG-based fMRI analysis can more accurately depict the whole-brain activation map and analyze emotional decision problems.

The effects of acute stress on episodic memory: A meta-analysis and integrative review

A growing body of research has indicated that acute stress can critically impact memory. However, there are a number of inconsistencies in the literature, and important questions remain regarding the conditions under which stress effects emerge as well as basic questions about how stress impacts different phases of memory. In this meta-analysis, we examined 113 independent studies in humans with 6,216 participants that explored effects of stress on encoding, postencoding, retrieval, or postreactivation phases of episodic memory. The results indicated that when stress occurred prior to or during encoding it impaired memory, unless both the delay between the stressor and encoding was very short and the study materials were directly related to the stressor, in which case stress improved encoding. In contrast, postencoding stress improved memory unless the stressor occurred in a different physical context than the study materials. When stress occurred just prior to or during retrieval, memory was impaired, and these effects were larger for emotionally valenced materials than neutral materials. Although stress consistently increased cortisol, the magnitude of the cortisol response was not related to the effects of stress on memory. Nonetheless, the effects of stress on memory were generally reduced in magnitude for women taking hormonal contraceptives. These analyses indicate that stress disrupts some episodic memory processes while enhancing others, and that the effects of stress are modulated by a number of critical factors. These results provide important constraints on current theories of stress and memory, and point to new questions for future research. (PsycINFO Database Record

Effect of acute psychological stress on response inhibition: An event-related potential study

This study aimed to investigate the effect of acute psychological stress on response inhibition and its electrophysiological correlates using a dual-task paradigm. Acute stress was induced by a primary task (mental arithmetic task), which consisted of a stress block and a control block. Response inhibition was measured using a secondary task (Go/NoGo task). In each trial, a Go/NoGo stimulus was presented immediately after the mental arithmetic task. The results revealed increased subjective stress and negative affect for the stress relative to control block, suggesting that the mental arithmetic task triggered a reliable stress response. ERPs locked to the Go/NoGo stimuli revealed that decreased P2 and increased N2 components were evoked for the stress block compared to the control block. These results demonstrated that acute psychological stress alters the response inhibition process by reducing the early selective attention process and enhancing the cognitive control process.

Balancing Automatic-Controlled Behaviors and Emotional-Salience States: A Dynamic Executive Functioning Hypothesis

Recently, there has been growing interest in understanding how executive functions are conceptualized in psychopathology. Since several models have been proposed, the major issue lies within the definition of executive functioning itself. Theoretical discussions have emerged, narrowing the boundaries between “hot” and “cold” executive functions or between self-regulation and cognitive control. Nevertheless, the definition of executive functions is far from a consensual proposition and it has been suggested that these models might be outdated. Current efforts indicate that human behavior and cognition are by-products of many brain systems operating and interacting at different levels, and therefore, it is very simplistic to assume a dualistic perspective of information processing. Based upon an adaptive perspective, we discuss how executive functions could emerge from the ability to solve immediate problems and to generalize successful strategies, as well as from the ability to synthesize and to classify environmental information in order to predict context and future. We present an executive functioning perspective that emerges from the dynamic balance between automatic-controlled behaviors and an emotional-salience state. According to our perspective, the adaptive role of executive functioning is to automatize efficient solutions simultaneously with cognitive demand, enabling individuals to engage such processes with increasingly complex problems. Understanding executive functioning as a mediator of stress and cognitive engagement not only fosters discussions concerning individual differences, but also offers an important paradigm to understand executive functioning as a continuum process rather than a categorical and multicomponent structure.

Better executive function under stress mitigates the effects of recent life stress exposure on health in young adults

Executive function is a neuropsychological construct that enables controlled cognitive processing, which has been hypothesized to enhance individuals' resilience to stress. However, little empirical work has directly examined how executive function under different conditions mitigates the negative effects of stress exposure on health. To address this issue, we recruited 110 healthy young adults and assessed their recent life stress exposure, executive function in either a stressful or non-stressful context, and current health complaints. Based on existing research, we hypothesized that individuals exhibiting better executive function following a laboratory-based stressor (but not a control task) would demonstrate weaker associations between recent stress exposure and health because they perceived recent life stressors as being less severe. Consistent with this hypothesis, better executive function during acute stress, but not in the absence of stress, was associated with an attenuated link between participants' recent life stress exposure and their current health complaints. Moreover, this attenuating effect was mediated by lesser perceptions of stressor severity. Based on these data, we conclude that better executive function under stress is associated with fewer health complaints and that these effects may occur by reducing individuals' perceptions of stressor severity. The data thus suggest the possibility of reducing stress-related health problems by enhancing executive function.

The impact of acute stress on cognitive functioning: a matter of cognitive demands?

INTRODUCTION

There is a controversy in the literature whether stress and related cortisol responses are beneficial or impairing for cognitive functioning. Conflicting results might be due to individual differences in stress reactivity and cognitive load of the applied tasks.

METHODS

N = 48 participants underwent the Socially Evaluated Cold Pressor Test and were confronted with the Frankfurter Aufmerksamkeits-Inventar-2 (FAIR-2) which is a low-load attention task and two subscales of the Intelligenz-Struktur-Test 2000 R (I-S-T 2000R) as a high-load reasoning task before and after the stressor. Participants were post hoc divided into high (stress induced cortisol increase of ≥1.5 nmol/l) vs. low-cortisol responders.

RESULTS

Cortisol responders showed an increased attentional performance in the post-stress condition (η² > .14). However, there were neither stress or responder main effects nor an interaction effect on reasoning abilities.

CONCLUSIONS

Results of the present study show that stress related changes in cognitive performance are due to individual differences in cortisol response and the cognitive load of the performed task. Future studies will show if these results are also valid for alternative cognitive tasks and if they can be replicated in female participants.