Effects of a single dose of cortisol on the neural correlates of episodic memory and error processing in healthy volunteers

Efficacy of the Mental Health App Intellect to Reduce Stress: Randomized Controlled Trial With a 1-Month Follow-up

BACKGROUND

Excessive stress is a major global health concern, particularly in young adults. Short skills-focused self-guided interventions (SGIs) on smartphones are a scalable way to improve stress-coping skills at the population level.

OBJECTIVE

In this randomized controlled trial, we aimed to examine the possible efficacy of a recently developed stress-coping SGI (Intellect) in improving psychological distress, relative to an active control group and 2 potential moderators of this predicted relationship (ie, psychological mindedness [PM] and coping self-efficacy [CSE]).

METHODS

University students (N=321) were randomly assigned to either an 8-day SGI on stress-coping or an active control group. Self-reported measures were obtained at baseline, after the intervention, and at the 1-month follow-up. The primary outcome was psychological stress (Psychological Stress Measure-9). Secondary outcomes were anxiety (Generalized Anxiety Disorder-7) and depressive symptoms (Patient Health Questionnaire-9). PM and CSE were assessed as potential moderators at baseline.

RESULTS

The final sample (n=264) included 188 (71.2%) female, 66 (25%) male, 7 (2.7%) nonbinary, and 3 (1.1%) others participants with a mean age of 22.5 (SD 5.41) years. The intervention group reported significantly lower perceived stress (partial eta-squared [ηp²]=0.018; P=.03) and anxiety (ηp²=0.019; P=.03) levels after intervention relative to the active control group. The effects on perceived stress levels remained statistically significant at the 1-month follow-up (ηp²=0.015; P=.05). Students with the lowest CSE and highest PM experienced the fastest decline in perceived stress levels (β=6.37, 95% Cl 2.98-9.75). Improvements in anxiety levels were not observed at 1-month follow-up. Similarly, no intervention effects were found for depression levels at postintervention and follow-up periods.

CONCLUSIONS

This study provides evidence that the Intellect stress-coping SGI is effective in reducing perceived stress and anxiety levels among university students. Mobile health apps are brief, scalable, and can make important contributions to public mental health.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04978896; https://www.clinicaltrials.gov/ct2/show/NCT04978896.

Combining proactive transcranial stimulation and cardiac biofeedback to substantially manage harmful stress effects

BACKGROUND

Previous studies have identified the dorsolateral prefrontal cortex (dlPFC) as a core region in cognitive emotional regulation. Transcranial direct current stimulations of the dlPFC (tDCS) and heart-rate variability biofeedback (BFB) are known to regulate emotional processes. However, the effect of these interventions applied either alone or concomitantly during an anticipatory stress remains unexplored.

OBJECTIVE

The study investigated the effect of anodal tDCS and BFB, alone or combined, on psychophysiological stress responses and cognitive functioning.

METHODS

Following a stress anticipation induction, 80 participants were randomized into four groups and subjected to a 15-min intervention: neutral video viewing (ctrl), left dlPFC anodal tDCS (tdcs), heart-rate variability biofeedback (bfb), or a combined treatment (bfb + tdcs). Participants were then immediately confronted with the stressor, which was followed by an assessment of executive functions. Psychophysiological stress responses were assessed throughout the experiment (heart rate, heart-rate variability, salivary cortisol).

RESULTS

The tdcs did not modulate stress responses. Compared with both ctrl and tdcs interventions, bfb reduced physiological stress and improved executive functions after the stressor. The main finding revealed that bfb + tdcs was the most effective intervention, yielding greater reduction in psychological and physiological stress responses than bfb.

CONCLUSIONS

Combining preventive tDCS with BFB is a relevant interventional approach to reduce psychophysiological stress responses, hence offering a new and non-invasive treatment of stress-related disorders. Biofeedback may be particularly useful for preparing for an important stressful event when performance is decisive.

An inverted U-shaped relationship between cortisol awakening response and same-day error monitoring function in healthy males

The cortisol awakening response (CAR) is thought to provide an energetic "boost" for the coming day and has been shown to be associated with prefrontal dependent function. The aim of the current study was to examine the relationship between the CAR and same-day neural activity following an error response task. Forty-six healthy males (22.25 years ± 1.98) collected saliva samples at 0, 30 and 45 min post-awakening to measure the CAR, and on the same afternoon event-related potential activity during error processing was measured. Although no association was observed between CAR and post-error behavior, a significant quadratic relationship was observed between CAR and Error-related Negativity (ERN) amplitude, and this association remained while controlling for confounding factors. This finding suggested the existence of an inverted U-shaped relationship between CAR and the same-day error-monitoring function in healthy males.

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.

Modeling the cardiac indices of stress and performance of nuclear power plant operators during simulated fault scenarios

Acute stress can affect cognitive processing and decrease performance in demanding, stressful situations. Here, we recorded the cardiac indices of stress, that is, the heart rate and heart rate variability together with the physical activity of nuclear power plant operators, and examined their association with crew performance, while the operator crews were managing simulated incident and accident situations. Crew performance was evaluated both by the operator instructor and as the time taken to resolve the situation. In total, 64% of the variance in the information-seeking performance (adj-R²  = .64, p < .01), and 41% of variation in the performance time (adj-R²  = .41, p < .01) were explained by the psychophysiology. The cardiac measures indicated that increased stress was associated with poorer information-seeking performance and longer performance time. Increased physical activity was associated with poorer information seeking only. Otherwise, crew performance was robust, as the diagnosis and corrective actions, use of emergency operations procedures, and collaboration, were only weakly associated with the stress physiology. The association between information-seeking performance and stress might be explained by the larger requirement for cognitive processing at the information-gathering phase of the task. The results of the study show that psychophysiological measurements of stress and activity can provide valuable information on stress and its association with cognitive performance at work.

Conditioning cortisol in humans: design and pilot study of a randomized controlled trial

Background

Conditioning of physiological responses can be achieved by repeatedly pairing a previously neutral conditioned stimulus with the administration of a pharmacologically salient unconditioned stimulus. This type of conditioning has been effective for specific immune and endocrine responses, but results with regard to conditioning of cortisol, a key stress-regulatory parameter, are currently unclear. This paper describes a pharmacological conditioning design, optimized for the examination of effects of cortisol conditioning under both basal conditions and in response to stress.

Methods

A double-blind randomized controlled conditioning paradigm aimed at conditioning of cortisol is conducted in 48 healthy female volunteers. During the acquisition phase, a gustatory stimulus (conditioned stimulus) is paired with hydrocortisone (100 mg, capsulated, unconditioned stimulus) three times before being administered together with placebo during three evocation sessions. To investigate possible effects of cortisol conditioning in response to stress, participants are exposed to the Trier Social Stress Test during the third evocation session. Primary outcome measure of this study is the mean area under the curve of salivary cortisol during the first two evocation sessions. As secondary outcomes, self-reported affect and stress as well as alpha-amylase are investigated. A pilot study was conducted to ensure that this design is feasible to be used in a larger study.

Discussion

This study design provides an innovative opportunity to examine the conditioning of cortisol under basal conditions and in response to stress. Also, the possible effect of cortisol conditioning on secondary outcomes of self-reported affect and alpha-amylase can be investigated. If cortisol could successfully be conditioned, this would be of conceptual relevance, showing that hypothalamic pituitary adrenal (HPA) axis regulation can be influenced by associative learning processes. Eventually, this could also have important clinical implications for understanding and treating stress-related disorders in which HPA axis dysregulation might play a role.

Trial registration

Nederlands Trial Register, NTR4651. Registered on 29 July 2014

Electronic supplementary material

The online version of this article (10.1186/s40814-018-0382-5) contains supplementary material, which is available to authorized users.

Effects of milk-based phospholipids on cognitive performance and subjective responses to psychosocial stress: A randomized, double-blind, placebo-controlled trial in high-perfectionist men

OBJECTIVES

The aim of this study was to examine the stress-buffering potential of phospholipid (PL) intake on cognitive performance and neuroendocrine and psychological responses under conditions of psychosocial stress in a high-stress vulnerable (perfectionist) sample.

METHODS

Fifty-four high-perfectionist men consumed a 6-wk daily intake of a bovine milk-derived PL (2.7 g/d) or placebo drink in a randomized, double-blind, placebo-controlled, parallel groups design. Working memory, executive control function, and acute physiological/subjective responses to an acute psychosocial stressor were examined before and after the 6-wk PL or placebo intake.

RESULTS

PL intake improved post-stress reaction time performance on an attention-switching task (P = 0.01). No significant attenuation of the salivary cortisol stress response was shown. PL intake significantly increased mid-stress induction energetic arousal (P = 0.03). A non-significant reduction in anticipatory subjective stress was reported after PL intake (P = 0.06). Systolic and diastolic blood pressures (P<0.04 and P = 0.01, respectively) were significantly augmented in the PL condition.

CONCLUSIONS

Dietary intake of bovine milk PLs conferred cognitive performance benefit under conditions of psychosocial stress but failed to moderate cortisol response. Moderation of subjective response to stress exposure may have underpinned this performance protection.

Testosterone, Cortisol and Financial Risk-Taking

Both testosterone and cortisol have major actions on financial decision-making closely related to their primary biological functions, reproductive success and response to stress, respectively. Financial risk-taking represents a particular example of strategic decisions made in the context of choice under conditions of uncertainty. Such decisions have multiple components, and this article considers how much we know of how either hormone affects risk-appetite, reward value, information processing and estimation of the costs and benefits of potential success or failure, both personal and social. It also considers how far we can map these actions on neural mechanisms underlying risk appetite and decision-making, with particular reference to areas of the brain concerned in either cognitive or emotional functions.

Cardiac measures of nuclear power plant operator stress during simulated incident and accident scenarios

Maintaining optimal performance in demanding situations is challenged by stress-induced alterations in performance. Here, we quantified the stress of nuclear power plant (NPP) operators (N = 20) during a full-scale simulator training for incident and accident scenarios. We compared the ambulatory electrocardiography measurements of heart rate (HR) and heart rate variability (HRV), and self-reported stress during baselines and simulated scenarios. Perceived (scale 0-10) and physiologically measured stress were low during baseline after the scenarios and normal NPP operation (means 1.8-2.2, mean HR 75-80 bpm). During a cognitively challenging scenario simulating a sensor malfunction, the operators' stress was mild to moderate (mean 3.4; HR + 12% from baseline). During simulations of severe accidents of fire and radioactive steam leakage, the experienced stress and cardiac activity were on a moderate to high level (means 4.2 and 4.6; HR + 23% and + 14% from baseline, respectively). Cardiac activity paralleled the self-reported stress: correlation of self-reported stress to HR was 0.61 (p < .001) and to HRV features RMSSD, HF, LF/HF, SD1, and SD1/SD2 were -0.26, -0.28, 0.35, -0.40, and -0.39 (p < .01), respectively. The low shared variance (22%) between HR and physical activity further support the interpretation that the cardiac activity was strongly linked to the experience of stress and not accountable by operators' movement within the simulator. Cardiac measurements in naturalistic settings can thus reveal relevant information on acute stress with the benefit of not interrupting the primary task.

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

Core executive functions such as working memory, inhibition, and cognitive flexibility are integral to daily life. A growing body of research has suggested that acute stress may impair core executive functions. However, there are a number of inconsistencies in the literature, leading to uncertainty about how or even if acute stress influences core executive functions. We addressed this by conducting a meta-analysis of acute stress effects on working memory, inhibition, and cognitive flexibility. We found that stress impaired working memory and cognitive flexibility, whereas it had nuanced effects on inhibition. Many of these effects were moderated by other variables, such as sex. In addition, we compared effects of acute stress on core executive functions to effects of cortisol administration and found some striking differences. Our findings indicate that stress works through mechanisms aside from or in addition to cortisol to produce a state characterized by more reactive processing of salient stimuli but greater control over actions. We conclude by highlighting some important future directions for stress and executive function research.

Cortisol and testosterone increase financial risk taking and may destabilize markets

It is widely known that financial markets can become dangerously unstable, yet it is unclear why. Recent research has highlighted the possibility that endogenous hormones, in particular testosterone and cortisol, may critically influence traders’ financial decision making. Here we show that cortisol, a hormone that modulates the response to physical or psychological stress, predicts instability in financial markets. Specifically, we recorded salivary levels of cortisol and testosterone in people participating in an experimental asset market (N = 142) and found that individual and aggregate levels of endogenous cortisol predict subsequent risk-taking and price instability. We then administered either cortisol (single oral dose of 100 mg hydrocortisone, N = 34) or testosterone (three doses of 10 g transdermal 1% testosterone gel over 48 hours, N = 41) to young males before they played an asset trading game. We found that both cortisol and testosterone shifted investment towards riskier assets. Cortisol appears to affect risk preferences directly, whereas testosterone operates by inducing increased optimism about future price changes. Our results suggest that changes in both cortisol and testosterone could play a destabilizing role in financial markets through increased risk taking behaviour, acting via different behavioural pathways.

Chronic stress induces a hyporeactivity of the autonomic nervous system in response to acute mental stressor and impairs cognitive performance in business executives

The present study examined the incidence of chronic stress in business executives (109 subjects: 75 male and 34 female) and its relationship with cortisol levels, cognitive performance, and autonomic nervous system (ANS) reactivity after an acute mental stressor. Blood samples were collected from the subjects to measure cortisol concentration. After the sample collection, the subjects completed the Lipp Inventory of Stress Symptoms for Adults and the Stroop Color-Word Test to evaluate stress and cognitive performance levels, respectively. Saliva samples were collected prior to, immediately after, and five minutes after the test. The results revealed that 90.1% of the stressed subjects experienced stress phases that are considered chronic stress. At rest, the subjects with chronic stress showed higher cortisol levels, and no gender differences were observed. No differences were found between the stressed and non-stressed subjects regarding salivary amylase activity prior to test. Chronic stress also impaired performance on the Stroop test, which revealed higher rates of error and longer reaction times in the incongruent stimulus task independently of gender. For the congruent stimulus task of the Stroop test, the stressed males presented a higher rate of errors than the non-stressed males and a longer reaction time than the stressed females. After the acute mental stressor, the non-stressed male group showed an increase in salivary alpha-amylase activity, which returned to the initial values five minutes after the test; this ANS reactivity was not observed in the chronically stressed male subjects. The ANS responses of the non-stressed vs stressed female groups were not different prior to or after the Stroop test. This study is the first to demonstrate a blunted reactivity of the ANS when male subjects with chronic psychological stress were subjected to an acute mental stressor, and this change could contribute to impairments in cognitive performance.

High cortisol awakening response is associated with impaired error monitoring and decreased post-error adjustment

The cortisol awakening response (CAR), a rapid increase in cortisol levels following morning awakening, is an important aspect of hypothalamic-pituitary-adrenocortical axis activity. Alterations in the CAR have been linked to a variety of mental disorders and cognitive function. However, little is known regarding the relationship between the CAR and error processing, a phenomenon that is vital for cognitive control and behavioral adaptation. Using high-temporal resolution measures of event-related potentials (ERPs) combined with behavioral assessment of error processing, we investigated whether and how the CAR is associated with two key components of error processing: error detection and subsequent behavioral adjustment. Sixty university students performed a Go/No-go task while their ERPs were recorded. Saliva samples were collected at 0, 15, 30 and 60 min after awakening on the two consecutive days following ERP data collection. The results showed that a higher CAR was associated with slowed latency of the error-related negativity (ERN) and a higher post-error miss rate. The CAR was not associated with other behavioral measures such as the false alarm rate and the post-correct miss rate. These findings suggest that high CAR is a biological factor linked to impairments of multiple steps of error processing in healthy populations, specifically, the automatic detection of error and post-error behavioral adjustment. A common underlying neural mechanism of physiological and cognitive control may be crucial for engaging in both CAR and error processing.

Stress-induced cortisol secretion impairs detection performance in x-ray baggage screening for hidden weapons by screening novices

Aviation security strongly depends on screeners' performance in the detection of threat objects in x-ray images of passenger bags. We examined for the first time the effects of stress and stress-induced cortisol increases on detection performance of hidden weapons in an x-ray baggage screening task. We randomly assigned 48 participants either to a stress or a nonstress group. The stress group was exposed to a standardized psychosocial stress test (TSST). Before and after stress/nonstress, participants had to detect threat objects in a computer-based object recognition test (X-ray ORT). We repeatedly measured salivary cortisol and X-ray ORT performance before and after stress/nonstress. Cortisol increases in reaction to psychosocial stress induction but not to nonstress independently impaired x-ray detection performance. Our results suggest that stress-induced cortisol increases at peak reactivity impair x-ray screening performance.

Dose-dependent effects of hydrocortisone infusion on autobiographical memory recall

The glucocorticoid hormone cortisol has been shown to impair episodic memory performance. The present study examined the effect of two doses of hydrocortisone (synthetic cortisol) administration on autobiographical memory retrieval. Healthy volunteers (n = 66) were studied on two separate visits, during which they received placebo and either moderate-dose (0.15 mg/kg IV; n = 33) or high-dose (0.45 mg/kg IV; n = 33) hydrocortisone infusion. From 75 to 150 min post-infusion subjects performed an Autobiographical Memory Test and the California Verbal Learning Test (CVLT). The high-dose hydrocortisone administration reduced the percent of specific memories recalled (p = .04), increased the percent of categorical (nonspecific) memories recalled (p < .001), and slowed response times for categorical memories (p < .001), compared with placebo performance. Under moderate-dose hydrocortisone the autobiographical memory performance did not change significantly with respect to percent of specific or categorical memories recalled or reaction times. Performance on the CVLT was not affected by hydrocortisone. These findings suggest that cortisol affects accessibility of autobiographical memories in a dose-dependent manner. Specifically, administration of hydrocortisone at doses analogous to those achieved under severe psychosocial stress impaired the specificity and speed of retrieval of autobiographical memories.

Gut memories: towards a cognitive neurobiology of irritable bowel syndrome

The brain and the gut are engaged in continual crosstalk along a number of pathways collectively termed the 'brain-gut axis'. Over recent years it has become increasingly clear that dysregulation of the axis at a number of levels can result in disorders such as irritable bowel syndrome (IBS). With recent advances in neuroimaging technologies, insights into the neurobiology of IBS are beginning to emerge. However the cognitive neurobiology of IBS has remained relatively unexplored to date. In this review we summarise the available data on cognitive function in IBS. Moreover, we specifically address three key pathophysiological factors, namely; stress, immune activation and chronic pain, together with other factors involved in the manifestation of IBS, and explore how each of these components may impact centrally, what neurobiological mechanisms might be involved, and consider the implications for cognitive functioning in IBS. We conclude that each factor addressed could significantly impinge on central nervous system function, supporting the view that future research efforts must be directed towards a detailed assessment of cognitive function in IBS.

Acute glucocorticoid effects on the multicomponent model of working memory

OBJECTIVE

In comparison with basal physiological levels, acute, high levels of cortisol affect learning and memory. Despite reports of cortisol-induced episodic memory effects, no study has used a comprehensive battery of tests to evaluate glucocorticoid effects on the multicomponent model of working memory. Here, we report the results of a double-blind, placebo-controlled, between-subjects study.

METHODS

Twenty healthy young men were randomly assigned to either acute cortisol (30 mg hydrocortisone) or placebo administration. Participants were subjected to an extensive cognitive test battery that evaluated all systems of the multicomponent model of working memory, including various executive domains (shifting, updating, inhibition, planning and access to long-term memory).

RESULTS

Compared with placebo, hydrocortisone administration increased cortisol blood levels and impaired working memory in storage of multimodal information in the episodic buffer and maintenance/reverberation of information in the phonological loop. Hydrocortisone also decreased performance in planning and inhibition tasks, the latter having been explained by changes in storage of information in working memory.

CONCLUSIONS

Thus, hydrocortisone acutely impairs various components of working memory, including executive functioning. This effect must be considered when administering similar drugs, which are widely used for the treatment of many clinical disorders.

The use of the EEG in measuring therapeutic drug action: focus on depression and antidepressants

A major issue in proof of concept studies and early clinical trials of novel therapeutic agents is that the active drugs can often have a relatively small additional effect compared with placebo. This is especially the case in psychiatry when we usually have no direct method of measuring the pathology underlying the disorder being studied but, rather, have to rely on the subjective assessment of psychiatric symptoms. The use of the electroencephalogram (EEG) offers two potential major means of addressing this problem. First it is able to provide direct data relating to neural activity that may be abnormal in certain disorders. As such there are opportunities for utilizing the EEG in a variety of ways as an objective outcome measure. Second there is growing evidence that in certain circumstances the EEG can be used to predict which patients are likely to respond to treatment, thus potentially increasing the power of studies by decreasing non-response rates and increasing mean changes in outcome measure. Both of these uses of the EEG are illustrated in reference to the study of mood disorders and in particular depression and its treatment with antidepressants.

Oral cortisol impairs implicit sequence learning

RATIONALE

Glucocorticoids have been shown to affect declarative memory, an explicit form of memory for facts and events operated by medial temporal lobe structures. Recent neuroimaging data suggest that the medial temporal lobe (including the hippocampus) is also active in implicit sequence learning.

OBJECTIVES

The aim of the present study was to investigate whether implicit sequence learning may also be affected by glucocorticoid administration.

METHODS

Oral cortisol (30 mg) was given to 29 healthy subjects whereas 31 control subjects received placebo. One hour after treatment all volunteers performed five consecutive blocks of a five-choice serial reaction time task by responding to colored lights by pressing buttons of the same color. The subjects responded without knowing to a quasi-randomized stimulus sequence, including higher-order sequential regularities (a combination of two colors that predicted the following target color). The reaction speed of every button-press (100 per block) was determined and difference scores were calculated as a proof of learning.

RESULTS

Both groups showed significant implicit sequence learning throughout the experiment. However, we found an impaired learning performance of the cortisol group compared with the placebo group. Further analysis revealed that a delayed learning in the cortisol group occurred at the very beginning of the task.

CONCLUSIONS

This study is the first human investigation indicating impaired implicit memory function after exogenous administration of the stress hormone cortisol. This effect may depend on hippocampus engagement in implicit sequence learning, but the involvement of other brain structures is also discussed.

Abnormal cortisol awakening response predicts worse cognitive function in patients with first-episode psychosis

BACKGROUND

Cognitive impairment, particularly in memory and executive function, is a core feature of psychosis. Moreover, psychosis is characterized by a more prominent history of stress exposure, and by dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. In turn, stress exposure and abnormal levels of the main HPA axis hormone cortisol are associated with cognitive impairments in a variety of clinical and experimental samples; however, this association has never been examined in first-episode psychosis (FEP).

METHOD

In this study, 30 FEP patients and 26 controls completed assessment of the HPA axis (cortisol awakening response and cortisol levels during the day), perceived stress, recent life events, history of childhood trauma, and cognitive function. The neuropsychological battery comprised general cognitive function, verbal and non-verbal memory, executive function, perception, visuospatial abilities, processing speed, and general knowledge.

RESULTS

Patients performed significantly worse on all cognitive domains compared to controls. In patients only, a more blunted cortisol awakening response (that is, more abnormal) was associated with a more severe deficit in verbal memory and processing speed. In controls only, higher levels of perceived stress and more recent life events were associated with a worse performance in executive function and perception and visuospatial abilities.

CONCLUSIONS

These data support a role for the HPA axis, as measured by cortisol awakening response, in modulating cognitive function in patients with psychosis; however, this association does not seem to be related to the increased exposure to psychosocial stressors described in these patients.

Changes in physiological stress and self-reported mood in younger and older adults after exposure to a stressful task

The objective of the current study was to compare the trajectories of physiological levels of stress and self-report measures of mood in younger and older adults and to examine how a stress induction would affect performance. The current study examined physiological and subjective indicators of stress and mood before, mid-way through, and after being exposed to a stressful computer task. Stress levels and negative affect increased after stress induction relative to levels before and after the stressful task. Practice on the task helped to improve performance (accuracy and reaction time) but high workload measured during the task mitigated accuracy in younger and older adults, whereas it enhanced response speed in younger adults.

Effects of cortisol on the laterality of the neural correlates of episodic memory

Alterations in the laterality of cortical activity have been shown in depressive illnesses. One possible pathophysiological mechanism for this is an effect of corticosteroids. We have previously demonstrated that endogenous cortisol concentrations correlate with the asymmetry of cortical activity related to episodic memory in healthy subjects and depressed patients. To further-examine whether this is due to a causal effect of cortisol on the laterality of episodic memory, we studied the effect of exogenous administration of cortisol in healthy subjects. Twenty-three right-handed healthy male volunteers were tested in a double-blind cross-over study. Event-related potentials (ERPs) were recorded during an episodic memory task following a four-day course of 160mg/day cortisol or placebo. Low-resolution brain electromagnetic tomography (LORETA) was used to identify brain regions involved in the neurocognitive task. Cortisol levels were measured in saliva samples. ERP and LORETA analysis following placebo demonstrated significant left parahippocampal activation associated with successful retrieval. Cortisol led to a decrease in the mean early frontal ERP voltage and an increase in the late right ERP voltage. LORETA suggested this to be due to a significant increased late activation of the right superior frontal gyrus. There was no significant effect of cortisol on episodic memory performance. This study suggests that exogenous cortisol leads to more positive-going waveforms over the right than the left hemisphere, possibly due to increased monitoring of the products of retrieval. The results support the hypothesis of causal effects of cortisol on the laterality of cortical activity occurring during an episodic memory task.

Cortisol inhibits neuroplasticity induction in human motor cortex

We investigated whether plasticity of human motor cortex (M1) is influenced by time of day, and whether changes in circulating levels of cortisol contribute to this effect. Neuroplasticity was induced using paired associative stimulation (PAS), involving electrical stimulation of left median nerve, paired with transcranial magnetic stimulation over the right M1 25 ms later (90 pairs at 0.05 Hz). Surface EMG was recorded from the left abductor pollicis brevis (APB) and first dorsal interosseous muscle. Cortisol levels were assessed from saliva. Time-of-day modulation of PAS effectiveness was assessed in 25 subjects who were tested twice, at 8:00 A.M. and 8:00 P.M. on separate days. In a second double-blind study, 17 subjects were tested with PAS at 8:00 P.M. on two occasions after administration of oral hydrocortisone (24 mg) or placebo. The motor-evoked potential (MEP) in resting APB increased significantly after PAS in the evening (when endogenous cortisol levels were low), but not in the morning. Oral hydrocortisone prevented facilitation of the APB MEP after PAS, and in the drug study, mean salivary cortisol levels were negatively associated with PAS effectiveness. The GABA(B)-mediated cortical silent period for APB was longer in the morning than in the evening, and was lengthened by PAS and oral hydrocortisone. We conclude that neuroplasticity in human M1 and GABA(B)-dependent intracortical inhibitory systems are influenced by time of day and modified by circulating levels of cortisol.

Effect of cortisol levels on working memory performance in elderly subjects with Alzheimer's disease

BACKGROUND: Subjects with Alzheimer's disease (AD) have elevated cortisol levels as a result of hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Acute administration of hydrocortisone has been associated with working memory (WM) performance in young adults. OBJECTIVE: To investigate whether cortisol levels are associated with WM performance in subjects with AD. METHOD: Eighty subjects were included, comprising 40 patients with mild AD and 40 healthy elderly controls. WM was assessed using the Digit Span Backward test (DSB). Saliva samples were collected to determine cortisol levels. RESULTS: AD subjects had poorer performance on the DSB than controls (p=0.002) and also presented higher levels of cortisol than control group (p=0.04). No significant correlation was observed between the DSB and cortisol levels in both groups (r= -0.29). CONCLUSION: In this study, elevated cortisol levels were not associated with poorer WM performance in patients with AD or in healthy elderly subjects.

Enhanced effects of cortisol administration on episodic and working memory in aging veterans with PTSD

Though both glucocorticoid alterations and memory impairments have been noted in posttraumatic stress disorder (PTSD), it is not clear if these phenomena are causally linked. As there is emerging evidence that these domains become further altered in PTSD with increasing age, it is of interest to examine these relationships in an older cohort. Aging (mean age, 62.7+/-8.9; range, 52-81) combat veterans with (n=13) and without (n=17) PTSD received an intravenous bolus of 17.5 mg hydrocortisone (cortisol), a naturally occurring glucocorticoid, or placebo in a randomized, double-blind manner, on two mornings approximately 1-2 weeks apart. Neuropsychological testing to evaluate episodic and working memory performance was performed 75 min later. Cortisol enhanced episodic memory performance in both groups of subjects, but enhanced elements of working memory performance only in the PTSD+ group. The preferential effect of cortisol administration on working memory in PTSD may be related to the superimposition of PTSD and age, as cortisol had impairing effects on this task in a previously studied, younger cohort. The findings suggest that there may be opportunities for developing therapeutic strategies using glucocorticoids in the treatment of aging combat veterans.

The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition

In this review, we report on studies that have assessed the effects of exogenous and endogenous increases in stress hormones on human cognitive performance. We first describe the history of the studies on the effects of using exogenous stress hormones such as glucocorticoids as anti-inflammatory medications on human cognition and mental health. Here, we summarize the cases that led to the diagnosis of glucocorticoid-induced 'steroid psychosis' in human populations and which demonstrated that these stress hormones could thus cross the blood-brain barrier and access the brain where they could influence cognition and mental health. We then summarize studies that assessed the effects of the exogenous administration of glucocorticoids on cognitive performance supported by the hippocampus, the frontal lobes and amygdala. In the second section of the paper, we summarize the effects of the endogenous release of glucocorticoids induced by exposure to a stressful situation on human cognition and we further dissociate the effects of emotion from those of stress on human learning and memory. Finally, in the last section of the paper, we discuss the potential impact that the environmental context to which we expose participants when assessing their memory could have on their reactivity to stress and subsequent cognitive performance. In order to make our point, we discuss the field of memory and aging and we suggest that some of the 'age-related memory impairments' observed in the literature could be partly due to increased stress reactivity in older adults to the environmental context of testing. We also discuss the inverse negative correlations reported between hippocampal volume and memory for young and older adults and suggest that these inverse correlations could be partly due to the effects of contextual stress in young and older adults, as a function of age-related differences in hippocampal volume.

Individual differences in cortisol levels and performance on a test of executive function in men and women

Despite evidence for a high concentration of corticosteroid receptors in prefrontal cortex, little research has examined the relationship between cortisol and prefrontal cortical function other than working memory. We investigated the association between salivary cortisol levels and performance on the Wisconsin Card Sorting Test (WCST) of executive function and on a test of mental rotation (to test specificity of the relationship between cortisol and cognitive performance) in men and women (n=116, ages 17-22). Higher cortisol levels at the beginning of the test session were associated with more errors in women on the WCST and fewer errors in men. However, men's cortisol levels were lower than women's at this point in time. Cortisol levels were not associated with mental rotation scores. Our results suggest that individual differences in cortisol levels among participants upon arrival to a test situation influence performance on a task involving the prefrontal cortex.

Cortisol responses of healthy volunteers undergoing magnetic resonance imaging

Self-reported anxiety is associated with various medical procedures, including structural and functional magnetic resonance imaging (MRI). The present study tested the hypothesis that MRI scanning would be associated with elevated cortisol levels in participants with no prior scanning experience. Baseline and post-scan cortisol levels, as well as measures of state and trait anxiety, were obtained from scanner-naive (n = 6) and scanner-experienced (n = 8) research participants. The anxiety scores and cortisol responses of the scanner-naive and scanner-experienced participants were compared. Subjects novel to MRI were no more anxious before the scan than were subjects familiar with the MRI examination, but the scanner-naive subjects manifested heightened post-scan cortisol secretion when compared to their pre-scan level and when compared to the scanner-experienced participants. The results are consistent with the hypothesis that the scanning environment can induce cortisol elevations and are congruent with the well-established effects of acute stressors on activity of the hypothalamic-pituitary-adrenal (HPA) axis. The implications for neuroimaging studies are discussed.

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.

Opposite effects of depression and antidepressants on processing speed and error rate

Depressions increase reaction times and antidepressant treatment decreases them. Is it possible to get information, how these two conditions affect the stimulus-response pathway? Therefore, auditory and visual, left-hand and right-hand, simple and choice reaction times were measured in 38 patients with depression and 30 healthy control subjects. From these data, the minimal reaction times and the error rates were calculated. In the first study, the reaction times and error rates of patients with depression were correlated with the antidepressant doses. In the second study, the differences between medicated, depressive patients and healthy control subjects were investigated. The result of the first study was that antidepressant doses correlated negatively with reaction times but positively with error rates. In the second study, the patients with depression showed increased reaction times but reduced error rates compared to healthy control subjects. The auditory tasks were more affected than the visual tasks and the minimal reaction times more than the median reaction times. Therefore, we concluded that depression and antidepressant treatment had opposite effects on reaction times and error rates. The findings in minimal reaction times and auditory tasks suggest a special involvement of early cortical auditory processing in depression and antidepressant treatment.

Stress facilitates consolidation of verbal memory for a film but does not affect retrieval

The effect of psychosocial stress on distinct memory processes was investigated in 157 college students using a brief film, which enabled comparison of verbal and visual memory by using a single complex stimulus. Participants were stressed either following stimuli presentation (consolidation) or before testing 48 hr later (retrieval) and were compared with no-stress controls. Salivary cortisol was measured before and 20 min after stress. The consolidation group significantly outperformed controls on total and verbal film scores. Stress did not impair retrieval relative to controls. Exploratory analyses revealed a significant correlation between cortisol and verbal scores across all groups (r = .18). Results provide the first evidence of a facilitative effect of a stressor on verbal memory, but failed to replicate retrieval findings.

Cortisol and memory retrieval in women: influence of menstrual cycle and oral contraceptives

RATIONALE

Studies in rodents observed that the effects of stress on memory are modulated by gonadal hormones. In animals and humans, stress and cortisol treatment impairs memory retrieval.

OBJECTIVES

To investigate if the acute impairing effect of cortisol on memory retrieval in women is influenced by endogenous or exogenous gonadal steroids.

METHODS

Three groups of women were studied: women during mensis (n=13), women in the luteal phase (n=14), and women using oral contraceptives (OCs; n=20). In a double-blind crossover fashion, they received cortisol (30 mg) or placebo 1 h prior to memory retrieval testing.

RESULTS

Overall cortisol led to a significant impairment of memory retrieval. Further exploratory analysis using t tests showed that both groups of naturally cycling women were significantly impaired (p<0.05), while no effect was apparent in the OC users (p=0.29).

CONCLUSIONS

The current results could suggest that OC use is associated with a reduced sensitivity of the brain to acute cortisol elevations. In contrast, menstrual-cycle-associated changes in estradiol and progesterone concentrations appear to have no strong influence on this acute cortisol effect. The underlying neurobiological mechanisms of these behavioral findings remain to be elucidated.

Hyperactive action monitoring during motor-initiation in conversion paralysis: an event-related potential study

Conversion paralysis (CP) is featured by a stress-induced tonic immobility. Although the neural correlates of this psychiatric condition remain largely unexplored, previous reports showed CP to be associated with anterior cingulate cortex (ACC) hyperactivity. We examined the ACC action monitoring function by recording event-related potentials (ERPs) when conversion patients (n = 6) with unilateral arm paresis made speeded responses with their affected and healthy arms on a flankers task. During this task, pre-response ACC action monitoring is reflected in the N2 ERP component, which is increased when incongruent stimuli lead to simultaneously activated competing response tendencies. The results showed that the N2 congruency effects were significantly increased for responses with affected hands compared to healthy hands. There were no such results for post-response monitoring. This study is the first to present electrophysiological correlates of action monitoring in CP and suggests ACC to be hyperactive when movements with affected arms are to be initiated.

The effects of stress-induced cortisol responses on approach-avoidance behavior

High glucocorticoid stress-responses are associated with prolonged freezing reactions and decreased active approach and avoidance behavior in animals. The present study was designed to investigate the effects of cortisol responses and trait avoidance on approach-avoidance behavior in humans. Twenty individuals were administered a computerized approach-avoidance (AA)-task before and after stress-induction (Trier Social Stress Test). The AA-task involved a reaction time (RT) task, in which participants made affect congruent and affect incongruent arm movements towards positive and threatening social stimuli. Affect congruent responses involved arm extension (avoidance) in response to angry faces and arm flexion (approach) in response to happy faces. Reversed responses were made in affect incongruent instruction conditions. As expected, participants with high cortisol responses showed significantly decreased RT congruency-effects in a context of social stress. Low trait avoidance was also associated with diminished congruency-effects during stress. However, the latter effect disappeared after controlling for the effects of cortisol. In sum, in agreement with animal research, these data suggest that high cortisol responses are associated with a decrease in active approach-avoidance behavior during stress. These findings may have important implications for the study of freezing and avoidance reactions in patients with anxiety disorders, such as social phobia and post-traumatic stress disorder.

Hormetic influence of glucocorticoids on human memory

In this paper, we discuss the effects of glucocorticoids on human learning and memory using the recent model of hormesis proposed by Calabrese and collaborators. Although acute increases in glucocorticoids have been shown to impair memory function in humans, other studies report no such impairments or, in contrast, beneficial effects of acute glucocorticoid increases on human memory function. We summarize these studies and assess whether the wealth of data obtained in humans with regard to the effects of acute increase of glucocorticoids on human cognition are in line with a hormetic function. We then discuss several factors that will have to be taken into account in order to confirm the presence of a hormetic function between glucocorticoids and human cognitive performance.

Drug-induced stimulation and suppression of action monitoring in healthy volunteers

RATIONALE

Action monitoring has been studied extensively by means of measuring the error-related negativity (ERN). The ERN is an event-related potential (ERP) elicited immediately after an erroneous response and is thought to originate in the anterior cingulate cortex (ACC). Although the ACC has a central role in the brain, only a few studies have been performed to investigate directly the effects of drugs on action monitoring. A recent theory argues that the mesencephalic dopamine system carries an error signal to the ACC, where it generates the ERN.

METHODS

ERPs and behavioral measurements were obtained from 12 healthy volunteers performing an Eriksen Flankers task. On each of the 4 test days, the stimulant D-amphetamine, the sedative lorazepam, the antidepressant mirtazapine, or a placebo was orally administered in a double-blind, four-way crossover design.

RESULTS

The indirect dopamine agonist amphetamine led to a strong enlargement of ERN amplitudes without affecting reaction times. Lorazepam and mirtazapine both showed slowing of responses, but only lorazepam led to reduced ERN amplitudes.

CONCLUSIONS

Administration of amphetamine leads to stimulated action monitoring, reflected in increased ERN amplitudes. This result provides evidence for dopaminergic involvement in action monitoring and is in line with differences in ERN amplitude found in neuropsychiatric disorders also suggesting dopaminergic involvement. The different effects for lorazepam and mirtazapine are probably caused by the neurobiological characteristics of these two types of sedation. Action monitoring is suppressed after administration of lorazepam, because the GABAergic pathways directly inhibit ACC functioning, whereas the histaminergic pathways of mirtazapine do not innervate the ACC directly.