Examination stress and components of working memory

Previous research suggests that stress can influence a broad range of memory functions. In this study we investigated the effect of a naturalistic stressor, examination stress, on working memory in young adults. In order to accomplish this aim, participants were tested on psychological and hormonal measures of stress and on Digit Span, once during a low stress period and once during a high stress period. The high examination stress condition was associated with an increase in cortisol and subjective impressions of stress. Although Digits Forward performance did not vary with examination stress, Digits Backward performance improved. These findings suggest that mild increases in stress are associated with improvement in the manipulation component of working memory. However, no correlations were found between working memory and either cortisol or psychological stress. Thus the mechanism by which mild naturalistic stressors improve the manipulation component of working memory needs further investigation.     

Male and female psychoneuroendocrine response to examination stress: A case report

Urinary catecholamine levels were investigated in one female and one male Ph.D. candidate during public defense of their Ph.D. theses as well as during 2 weeks preceding and 1 week following these examinations. Although females, in comparison to males, usually tend to show a weak adrenaline response to mental stress, a threefold increase was observed in both subjects. The results support the assumption that sex differences in adrenal-medullary responsiveness to stress is not determined by sex-specific biological factors alone and that a “male” responsiveness may be observed in achievement-oriented females exposed to a challenging real-life situation. Effects on urinary measures of cortisol obtained from the male subject resembled effects on adrenaline, showing that this kind of real-life stressor affects the sympathetic-adrenal medullary and the pituitary-adrenocortical systems similarly.     

Sex,stress, and fear: Individual differences in conditioned learning

It has long been recognized that humans vary in their conditionability, yet the factors that contribute to individual variation in emotional learning remain to be delineated. The goal of the present study was to investigate the relationship among sex, stress hormones, and fear conditioning in humans. Forty-five healthy adults (22 females) underwent differential delay conditioning, using fear-relevant conditioned stimuli and a shock unconditioned stimulus. Salivary cortisol samples were taken at baseline and after acquisition training and a 24-h-delayed retention test. The results showed that acquisition of conditioning significantly correlated with postacquisition cortisol levels in males, but not in females. This sex-specific relationship was found despite similar overall levels of conditioning, unconditioned responding, and cortisol. There was no effect of postacquisition cortisol on consolidation of fear learning in either sex. These findings have implications for the understanding of individual differences in fear acquisition and risk factors for the development of affective disorders.     

Neuroendocrine responses to psychological stress in eumenorrheic and oligomenorrheic women

Neuroendocrine adaptive responses to psychological stress include activation of the hypothalamic-pituitary-adrenal (HPA) axis and sometimes suppression of the hypothalamic-pituitary-gonadal (HPG) axis. In women who experience chronic stress, these responses are probably responsible for disturbances in the menstrual cycle. In the present experiment, we investigated the effect of an acutely stressful situation on the physiological and neuroendocrine responses in college age women. We hypothesized that females who are experiencing some degree of abnormal menstrual function or women who have less-robust cycles (oligomenorrheic females) would exhibit differences in gonadotropin secretion from eumenorrheic females when exposed to psychological stressors. Fifteen women completed this study: eumenorrheic (n = 5) and oligomenorrheic women (n = 5) who experienced a series of psychological stressors, and eumenorrheic controls (n = 5). Blood samples were taken at 10 min intervals for 8 h (09:00-17:00) in each woman during the mid-follicular phase of the menstrual cycle. The psychological stressors were administered for 1 h beginning at 13:00 h. Luteinizing hormone (LH), growth hormone (GH) and cortisol were measured in each sample to assess the effect of stress on secretion of these hormones. Deconvolution analysis was used to analyze pulsatile hormone secretion and the approximate entropy (ApEn) statistic analyzed the regularity of release of each hormone. Although, there were significant changes in heart rate (HR), skin resistance (SR) and cortisol levels in the stressed women during the psychological stressor compared to resting baseline values but not in the controls, there was no difference in either LH or GH secretion between women who experienced stress and those who did not. Furthermore, there were no differences in the LH or GH secretion patterns in the oligomenorrheic and eumenorrheic women exposed to the psychological stressor.     

The effects of exposure to an acute naturalistic stressor on working memory, state anxiety and salivary cortisol concentrations

Exposure to an acute naturalistic stressor induces both psychological and physiological changes in humans. The two studies reported here explored the impact of exposure to an acute naturalistic stressor on state anxiety, working memory and HPA axis activation (salivary cortisol). In both experiments, ten healthy male participants were exposed to an acute naturalistic stressor, helicopter underwater evacuation training (HUET), and their physiological and behavioural responses before (first study) and after (second study) the stressor were compared to ten non-stressed controls. The results of both experiments showed that working memory performance was preserved during anticipation of an acute stressor, but impairments were observed immediately after stress exposure. Participants reported significantly higher state anxiety levels during anticipation and following stress exposure, whereas significant elevations in cortisol levels were only observed 25 min post exposure to stress, but not before or immediately after stress exposure. The results of both experiments demonstrated a dissociation between behavioural and biochemical measures and provided evidence for a dissociation of the effects of stress on cognitive and physiological measures depending on the time of testing, with cognitive impairments most evident following stress exposure.     

Cognitive performance and morning levels of salivary cortisol and alpha-amylase in children reporting high vs. low daily stress perception

The aim of the present study was to assess the effects of daily stress perception on cognitive performance and morning basal salivary cortisol and alpha-amylase levels in healthy children aged 9-12. Participants were classified by whether they had low daily perceived stress (LPS, n = 27) or a high daily perceived stress (HPS, n = 26) using the Children Daily Stress Inventory (CDSI). Salivary cortisol and alpha-amylase were measured at awakening and 30 minutes later. Cognitive performance was assessed using the Cognitive Drug Research assessment system. The HPS group exhibited significantly poorer scores on speed of memory (p < .05) and continuity of attention (p < .05) relative to the LPS group. The HPS group also showed significantly lower morning cortisol levels at awakening and at +30 minutes measures in comparison with the LPS group (p < .05), and mean morning cortisol levels were negatively correlated with speed of memory (p < .05) in the 53 participants. No significant differences were observed between both groups in alpha-amylase levels. These findings suggest that daily perceived stress in children may impoverish cognitive performance via its modulating effects on the HPA axis activity.     

Type D personality and cardiac output in response to stress

Type D personality is predictive of adverse clinical outcome and psychological distress in cardiac patients. However, the mechanisms by which Type D affects health are largely unknown. This study (1) investigated the relationship between Type D and cardiovascular reactivity to experimentally induced stress and (2) tested the influence of Type D on subjective feelings of stress. Eighty four healthy young adults (50% males, mean (SD) age 22 (6.84) years), completed measures of Type D personality, stress arousal and a stress-inducing procedure involving a taxing mental arithmetic task. Cardiovascular measures were recorded throughout the experiment. Mixed measures ANOVA showed a significant main effect of Type D and a significant group by time effect of Type D on cardiac output in male participants. Type D males exhibit significantly higher cardiac output during the stressor phase compared to non-Type D males. However, there was no relationship between Type D and cardiovascular reactivity in females. In addition, Type D individuals exhibited significantly higher feelings of subjective stress compared to non-Type D's. These findings provide new evidence on Type D and suggest that Type D may affect health through increased cardiac output and higher subjective feelings of stress following acute stress.     

Behavioral and physiological correlates of stress related to examination performance in college chemistry students

This study was designed to assess physiological and behavioral correlates of academic stress during a college course in organic chemistry in the USA. Participants (45 females, 46 males, mean age 19.88 years) were screened for their basal hypothalamic-pituitary-adrenocortical activity using saliva samples collected at the beginning of the course and after each major test. Displacement activities (DAs) were observed during each test by videotaping students' behavior when they were taking the tests. These variables were then used as predictors of the students' achievement as measured by their grade point average (GPA) scores, American College Testing (ACT) scores, and their final grade in the class. Ninety-one students, enrolled in Organic Chemistry I at Marshall University during the summer of 2009, were recruited for this study. It was found that individual differences in the physiological stress responses are a factor in predicting the students' ability to pass a challenging class. A logistic model built on GPA, DAs during stress, and salivary hormone (cortisol and dehydroepiandrosterone) concentrations was able to correctly classify almost 90% of the students passing the class. The same model was not nearly as successful in determining the possible factors behind failing the class, because the classification success was just 52%, a figure close to chance. We conclude that a clear set of characteristics related to the students' ability and resilience to psychological stress are necessary to succeed in a challenging class. The reason behind dropping or failing a class could be less defined. These data indicated that investigating the physiological and behavioral propensities associated with psychological stress can help us better understand an individual's coping responses to a long-term challenging situation.     

The Relationship of Hardiness, Gender, and Stress to Health Outcomes in Adolescents

The present study examined the relationship between the hardiness components of commitment, control, and challenge, and the experience of physical and psychological symptoms in a sample of 150 (75 male, 75 female) adolescents. A measure of psychosocial stress was included to permit an examination of whether the hardiness components interact with stress in predicting health outcomes. Analyses revealed main effects of stress, gender, and the hardiness components of commitment and control for several of the health measures. More important was the finding of a consistent interaction of stress, gender, and hardiness for several of the health measures. Whereas low-stress males experienced few physical and psychological symptoms regardless of their levels of commitment and control, high-stress males experienced more problems when they were low rather than high in either commitment or control. The hardiness components did not interact with stress in the prediction of health outcomes among females.     

Brief,pre-retrieval stress differentially influences long-term memory depending on sex and corticosteroid response

Previous work has indicated that stress generally impairs memory retrieval. However, little research has addressed discrepancies that exist in this line of work and the factors that could explain why stress can exert differential effects on retrieval processes. Therefore, we examined the influence of brief, pre-retrieval stress that was administered immediately before testing on long-term memory in males and females. Participants learned a list of 42 words varying in emotional valence and arousal. Following the learning phase, participants were given an immediate free recall test. Twenty-four hours later, participants submerged their non-dominant hand in a bath of ice cold (Stress) or warm (No Stress) water for 3 min. Immediately following this manipulation, participants’ memory for the word list was assessed via free recall and recognition tests. We observed no group differences on short-term memory. However, male participants who showed a robust cortisol response to the stress exhibited enhanced long-term recognition memory, while male participants who demonstrated a blunted cortisol response to the stress exhibited impaired long-term recall and recognition memory. These findings suggest that the effects of brief, pre-retrieval stress on long-term memory are sex-specific and mediated by corticosteroid mechanisms.     

Granulocyte activation in humans is modulated by psychological stress and relaxation

Our aim was to study the possible relationship between psychological stress and granulocyte activation primarily in healthy students during an examination period (n = 11) and also in chronically anxious patients (n = 15). We employed cell surface markers: lactoferrin, L-selectin, alphaMbeta2-integrin and CD15s and flow cytometry to detect changes in the activation state of granulocytes, with the start of the stressed state in students at the beginning of an examination period, which was associated with elevated blood plasma cortisol level, and following relaxation hypnosis in both students, during their examination term, and patients. The ratios of all four types of marker-carrier granulocytes increased at the start of the examination period in students; an especially dramatic (ca. 5-fold) enhancement was observed in the proportion of lactoferrin-bearing cells relatively to the pre-examination term value. After hypnosis, the percentage of lactoferrin-exposing granulocytes decreased considerably both in students and in patients, by about half; a similar decrease was observed in the ratio of CD15s-carrier cells in patients. No significant alteration was observed during the study in state or trait anxiety levels, and in total or differential leukocyte counts. Thus, granulocyte activation could be associated with stress, while relaxation may facilitate reducing activation of these cells. In both groups of subjects, granulocyte surface lactoferrin appeared to be a sensitive "stress indicator". This needs further evaluation.     

Neural bases of moderation of cortisol stress responses by psychosocial resources

Psychosocial resources have been tied to lower psychological and biological responses to stress. The present research replicated this relationship and extended it by examining how differences in dispositional reactivity of certain neural structures may underlie this relationship. Two hypotheses were examined: (a) psychosocial resources are tied to decreased sensitivity to threat and/or (b) psychosocial resources are associated with enhanced prefrontal inhibition of threat responses during threat regulation. Results indicated that participants with greater psychosocial resources exhibited significantly less cortisol reactivity following a stress task, as predicted. Analyses using functional magnetic resonance imaging revealed that psychosocial resources were associated with greater right ventrolateral prefrontal cortex and less amygdala activity during a threat regulation task but were not associated with less amygdala activity during a threat sensitivity task. Mediational analyses suggest that the relation of psychosocial resources to low cortisol reactivity was mediated by lower amygdala activity during threat regulation. Results suggest that psychosocial resources are associated with lower cortisol responses to stress by means of enhanced inhibition of threat responses during threat regulation, rather than by decreased sensitivity to threat.     

Consequences of ‘tiger’ parenting: a cross‐cultural study of maternal psychological control and children's cortisol stress response

Parenting strategies involving psychological control are associated with increased adjustment problems in children. However, no research has examined the extent to which culture and psychological control predict children's stress physiology. We examine cultural differences in maternal psychological control and its associations with children's cortisol. Chinese (N = 59) and American (N = 45) mother‐child dyads participated in the study. Mothers reported on psychological control. Children's cortisol was collected during a stressor and two indices of Area Under the Curve (AUC) were computed: AUCg which accounts for total output, and AUCi, which captures reactivity. Results indicate that Chinese mothers reported higher levels of psychological control and Chinese children had higher levels of AUCg than their American counterparts. Across both cultures, psychological control was significantly associated with increased cortisol levels as indexed by AUCg. There were no associations for AUCi. Finally, mediation analyses demonstrated that psychological control fully explained cultural differences in children's cortisol stress response as indexed by AUCg.     

Gender differences in cardiovascular and hypothalamic-pituitary-adrenal axis responses to psychological stress in healthy older adult men and women

Gender differences in the neuroendocrine and cardiovascular response to psychological stress may contribute to the gender differences in the prevalence of diseases associated with hypothalamic-pituitary-adrenal (HPA) axis reactivity such as cardiovascular disease (CVD), diabetes and hypertension. We measured plasma ACTH, cortisol, heart rate (HR), and blood pressure (BP) responses in 8 men and 8 women (55-75 years) exposed to the Matt Stress Reactivity Protocol (MSRP), a psychological challenge. The MSRP elicited significant increases in HR, systolic-, and diastolic BP, ACTH and cortisol (all p<0.01). Men had significantly greater cortisol and diastolic BP responses compared to women (p<0.05). Additionally, a positive correlation between the ACTH and cortisol responses was only found in the males (r=0.71, p<0.05). There were no group differences in HR, systolic BP, or ACTH responses. We conclude, that among older adults, men respond to psychological stress with greater increases in cortisol, compared to women. This greater activation of the HPA axis could translate into an elevated risk for CVD, diabetes and hypertension and may be related to the higher prevalence of these diseases in males. Gender differences in brain structures and/or cognitive processes may be responsible for these sexually dimorphic stress responses.     

Does the level of physical exercise affect physiological and psychological responses to psychosocial stress in women?

ObjectivesTo test the Cross-Stressor Adaptation hypothesis for females by examining whether physically exercising young women show reduced physiological and psychological stress responses to a psychosocial stressor.DesignForty-seven healthy young women with different levels of physical exercise (17 not or rarely exercising, 15 moderately exercising, 15 vigorously exercising) underwent the Trier Social Stress Test for Groups (TSST-G); physiological and psychological stress responses during and after stress induction were compared.MethodANOVAs with repeated measures were used to compare stress reactivity and recovery between the three exercise groups. Heart rate and salivary free cortisol were used as indicators of physiological stress response, state anxiety, mood, and calmness as indicators of psychological stress response. For physiological stress reactivity, the areas under the curve with respect to the ground (AUC_G) were compared.ResultsIn all three exercise groups, experimentally induced stress led to a significant rise in heart rate, cortisol, and state anxiety; mood and calmness significantly decreased. As hypothesized, the pattern of the physiological stress response differed for the three exercise groups, with lowered reactivity in the more active groups. However, the psychological stress response partly went in the opposite direction: Exercising participants reported a higher mood decrease, suggesting a dissociation of the physiological and psychological stress responses.ConclusionsThe findings suggest that the Cross-Stressor Adaptation hypothesis is also valid for young women; however, only with regard to physiological stress response. The unexpected findings for psychological stress response need to be further explored in experimental studies.     

The cortisol awakening response: Associations with trait anxiety and stress reactivity

This study investigated the extent to which trait anxiety and state anxiety in response to stress are associated with the cortisol awakening response (CAR).Fifty-one healthy participants were recruited. State anxiety measures were taken in anticipation of and during a laboratory stressor. Salivary cortisol levels were measured immediately upon awakening (at 0, 15, 30, and 45 min) on two consecutive mornings. Cortisol awakening response was assessed by the area under the curve with respect to zero (AUC_G).The magnitude of the CAR was found to be negatively associated with both trait anxiety and anticipatory anxiety. Moreover, regression analysis showed that the effects of trait anxiety on the AUC_G were mediated by anticipatory anxiety.These results suggest that the CAR is influenced by trait anxiety. Moreover, the effect of trait anxiety on the CAR seems to operate by impacting on psychological stress reactivity (i.e., anticipatory anxiety).     

自尊与心理性应激的关系初探

自尊水平影响着个体在应激情境中的内分泌反应,在以人个人主义文化下的研究发现,由于低自尊具有较低的内部控制力,因此在应激情境中的唾液皮质醇反应更强烈。但是在中国集体主义文化中,由于集体性自我的评价是自尊的一个重要组成部分,高自尊更加期望集体或社会的积极性评价,因此假设在心理性应激情境下（即个体的能力被否定的时候）,高自尊的应激反应会比低自尊更加强烈。本研究以健康大学生为被试,分别以Rosenberg自尊量表和特里尔社会应激测试（TSST）为实验手段,以自尊量表得分、主观应激报告（5点量表）和客观应激参数（心率和唾液皮质醇）为指标,在中国文化背景下探讨自尊与心理性应激的关系。结果发现,在TSST开始时（20分钟）自尊与心率呈正相关,自尊水平越高,心率越快;在TSST结束后（60分钟）自尊与唾液皮质醇水平呈正相关,自尊水平越高,唾液皮质醇水平越高。总体来说,相对于低自尊被试而言,高自尊被试在心理性应激情境中的反应更为强烈。     

Repeated acute stress alters heart morphometry in male and female rats differently

Stress exerts deleterious effects on the cardiovascular system. Left ventricular hypertrophy has been identified as a risk factor for heart disease. The effects of stress on other heart parameters, including heart size and heart shape, are not well-characterized. In addition, the extent to which males and females differ in stress effects on these measures has not been examined, but may help to further explain gender differences in heart disease morbidity and mortality. The present experiment examined effects of mild daily stress on heart morphology and blood volume (obtained by ex-sanguination at decapitation) in 39 male and 40 female rats of two strains. Following 14 days of stress exposure, rats were killed and blood volume was measured. Heart length, heart weight, left ventricle cavity width, right ventricle width, lateral wall thickness, anterior wall thickness, posterior wall thickness, and septal wall thickness were measured. In males, after controlling for body weight, stress decreased heart length and left ventricle cavity width and increased septal wall thickness. In females, after controlling for body weight, stress reduced total blood volume, but did not significantly affect other heart parameters. These findings suggest that stress exposure can alter heart morphology and blood volume and that there are sex differences in these effects.     

Variation in hypothalamic-pituitary-adrenal axis activity among bullied and non-bullied children

We examined the relationship between being bullied during childhood and activity of the hypothalamic-pituitary-adrenal (HPA) axis as assessed through repeated measures of salivary cortisol. A non-clinical sample of 154 (74 boys) predominantly Caucasian middle-class 12-year-olds each provided detailed information about their experiences with bullying and six saliva samples were standardized across time and day. Children with a history of child maltreatment, diagnosed psychiatric illness, foster care placement, medication use (psychotropic and oral contraception) and aggression directed toward peers and/or family members were excluded. Using multilevel regression and applying orthogonal polynomial contrasts to model the observed circadian pattern in the data, we found that occasional and frequent verbal peer victimization was associated with hyposecretion of cortisol when controlling for sex, pubertal status, age, depression and anxiety. This relation, however, was moderated by sex. For boys, occasional exposure was associated with higher cortisol levels, whereas for girls exposure was associated with lower cortisol levels. The present study highlights the need to consider the plight of peer-victimized children seriously, as it is associated with alterations to the HPA axis that affect males and females differently, and likely diminishes a person's ability to cope with stress, possibly placing them at risk for psychopathology and ill health.     

Depressive symptoms, cortisol, and cognition during human aging: the role of negative aging perceptions

Depressive symptoms and memory impairments are associated with heightened stress hormone levels during aging. A factor that is related to memory deficits during aging is internalized negative aging stereotypes; the idea people have about the process of aging. In this study, we assessed the associations between internalized negative aging stereotypes, depressive symptoms, subjective and objective memory assessments, and cortisol concentration among older adults. Forty older adults aged between 58 and 85 years (18 females and 22 males; mean age?±?SD: 71.25?±?8.80 years) were assessed in this study. Measures of internalized negative aging stereotypes, depressive symptoms, and both subjective and objective memory performance were assessed. Salivary samples were obtained for measurement of cortisol concentration. Stepwise linear regressions were executed in our main analyses. Internalized negative aging stereotypes were associated with increased depressive symptoms and subjective memory complaints. No significant differences were observed for objective memory performance, or cortisol concentration. Internalized negative aging stereotypes are associated with increased depressive symptomatology and subjective complaints of memory; however, they do not predict increased cortisol concentration nor objective memory performance during aging. These results indicate that the mechanism underlying the association between internalized negative aging stereotypes and cognitive impairments may not be related to dysregulations of cortisol secretion among older adults.