Acute consolidation stress enhances reality monitoring in healthy young adults

Source monitoring refers to cognitive processes involved in making attributions about the origins of memories, knowledge, and beliefs. One particular type of source monitoring with ample practical significance is reality monitoring, i.e., the ability to discriminate between internally vs. externally generated memories. Abundant evidence indicates that exposure to acute stress enhances declarative memory consolidation. To date, no study has looked at whether exposure to acute stress during the consolidation phase may promote reality monitoring performance. The authors examined this by administering cold pressor stress (CPS) or a control procedure to participants (N = 80) after they had either performed or only imagined performing simple motor acts, and assessing reality monitoring 24 h later. When compared with the control condition, CPS significantly elevated salivary free cortisol concentrations and enhanced reality monitoring. Stress-induced cortisol responses, however, were found not to be related to improved reality monitoring performance. Our findings are consistent with the view that post-learning stress hormone-related activity may modulate source memory consolidation.     

Academic self-concept of ability and cortisol reactivity

The present study aimed to clarify the relationship between a school-specific trait (academic self-concept of ability [ASCA]) and hormonal stress response by using a trait-compatible stressor (test). First, we determined 52 students' ASCA scores for biology and measured their salivary cortisol concentration before and after a biology test (experimental group, n = 28) or a free writing task (control group, n = 24). For participants who took the test, statistical analysis indicated a significant negative correlation between ASCA score and cortisol response. In contrast, the control group showed a decrease in cortisol concentrations between test times and no correlation between cortisol concentration and ASCA scores were found. These findings indicated an interaction between ASCA scores and hormonal stress response when an academic-related stressor is present. Furthermore, these variables might influence each other adversely: high cortisol concentrations during a test situation may lead to greater feelings of insecurity, resulting in low ASCA scores and awareness of these low scores may lead to a further increase in cortisol, creating a vicious cycle.     

Stress impairs acquisition of delay eyeblink conditioning in men and women

In rodents stress impairs delay as well as trace eyelid conditioning in females, but enhances it in males. The present study tested the effects of acute psychosocial stress exposure on classical delay eyeblink conditioning in healthy men and women. In a between subject design, participants were exposed to psychosocial stress using the Trier Social Stress Test (TSST) or a control condition which was followed by a delay eyeblink classical conditioning procedure. Stress exposure led to a significant increase in salivary cortisol and impaired acquisition of conditioned eyeblink responses (CRs). This was evident by a later first CR and an overall lower CR rate of the stress group. The stress-induced acquisition impairment was observed in both women and men. Subjects failing to show a stress-induced cortisol increase (cortisol non-responder) were not impaired in acquisition. Our findings indicate that acute stress, possibly via activation of the hypothalamus–pituitary–adrenal (HPA) axis, reduces the ability to acquire a simple conditioned motor response in humans.     

儿童受欺负与急性社会应激中应激反应的关系

研究旨在考察受欺负经历与儿童下丘脑-垂体-肾上腺轴系统应激功能的关系。根据受欺负得分挑选出52名受欺负和未受欺负儿童,考察两类儿童在特里尔社会应激测验(Trier Social Stress Test,TSST)中的皮质醇分泌及主观紧张度的特征差异。结果发现:(1)在TSST中,受欺负者的皮质醇浓度显著高于未受欺负者;(2)两类儿童在TSST中的主观紧张度不存在显著差异。研究结果与慢性应激破坏HPA轴应激功能的过程是从敏化到钝化的理论假说相一致。     

Effects of pre-learning stress on memory for neutral, positive and negative words: Different roles of cortisol and autonomic arousal

Stress can have enhancing or impairing effects on memory. Here, we addressed the effect of pre-learning stress on subsequent memory and asked whether neutral and emotionally valent information are differentially affected by specific stress components, autonomic arousal and stress-induced cortisol. Ninety-six healthy men and women underwent either a stressor (modified cold pressor test) or a control warm water exposure. During stress, participants showed comparable autonomic arousal (heart rate, blood pressure), while 60 percent showed an increase of cortisol (responders vs. 40 percent non-responders). Ten minutes after the cold pressor test neutral, positive and negative words were presented. Free recall was tested 1 and 24 h later. Overall, positive and negative words were better recalled than neutral words. Stress enhanced the recall of neutral words independently of cortisol response. In contrast, the free recall of negative words was enhanced in cortisol responders in the 1-h but not 24-h test which might suggest different effects of cortisol on consolidation and reconsolidation processes. Recall for positive words was unaffected by stress-induced cortisol. To summarize, (i) pre-learning stress can enhance memory for neutral words independently of cortisol and (ii) stress effects on memory for negative words appear to rely on stress-induced cortisol elevations, the absence of this effect for positive words might be at least partly due to differences in arousal evoked by positive vs. negative words.     

Relationship disruption stress in human infants: a validation study with experimental and control groups

The current study examined whether the psychological stress of the still-face (SF) task (i.e. stress resulting from a parent's unresponsiveness) is a valid laboratory stress paradigm for evaluating infant cortisol reactivity. Given that factors external to the experimental paradigm, such as arriving at a new place, may cause an elevation in cortisol secretion; we tested the hypothesis that infants would show a cortisol response to the SF task but not to a normal FF task (control). Saliva was collected for cortisol measurement from 6-month-old infants (n?=?31) randomly assigned to either a repeated SF task or to a continuous FF task. Parent-infant dyads were videotaped. Salivary cortisol concentration was measured at baseline, 20, and 30?min after the start of the procedure. Infant salivary cortisol concentrations showed a significant increase over time for the SF task but not for the FF task. The results provide new evidence that the repeated SF task provides a psychological challenge that is due to the SF condition rather than to some non-task related factor; these results provide internal validity for the paradigm. The study offers new insight into the role of parent-infant interactions in the activation of the infant stress response system.     

Touch attenuates infants’ physiological reactivity to stress

Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still‐face (SF) and still‐face with maternal touch (SF+T). Maternal and infant cortisol levels were sampled at baseline, reactivity, and recovery and mother’s and infant’s cardiac vagal tone were measured during the free play, still‐face, and reunion episodes of the procedure. Cortisol reactivity was higher among infants in the SF condition and while cortisol decreased at recovery for infants in the SF+T, it further increased for those in the SF. Vagal tone showed a greater suppression when SF was not accompanied by maternal touch. Touch synchrony during free play was associated with higher infant vagal tone, whereas touch myssynchrony – maternal tactile stimulation while the infant gaze averts – correlated with higher maternal and infant cortisol. In humans, as in mammals, the provision of touch during moments of maternal unavailability reduces infants’ physiological reactivity to stress.     

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.     

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.     

Temporal relationships between plasma cortisol, corticosteroid-binding globulin (CBG), and the free cortisol index (FCI) in pigs in response to adrenal stimulation or suppression

The objective of this study was to document changes in plasma concentrations of total cortisol, porcine corticosteroid-binding globulin (pCBG), and the free cortisol index (FCI) in pigs over a 6-h period in response to adrenal stimulation or suppression. Twenty-four 8-week old pigs allotted in equal numbers were administered ACTH, dexamethasone or saline, and blood samples were collected every 15 min via an indwelling jugular catheter for 1 h prior to and 5 h following treatment. Total plasma cortisol increased in ACTH-treated pigs and decreased in dexamethasone-treated pigs within 0.25 and 0.5 h, respectively. In contrast, pCBG concentration was altered in an inverse fashion subsequent to the changes exhibited in total cortisol. FCI reflected the changes observed in total cortisol. These results further document the negative relationship that exists between circulating concentrations of plasma cortisol and pCBG, and illustrate that this association exists under conditions of acute stress in the pig.     

Stress and emotional memory retrieval: effects of sex and cortisol response

In some situations, memory is enhanced by stressful experience, while in others, it is impaired. The specific components of the stress-response that may result in these differing effects remain unclear, and the current study sought to address this knowledge gap. Forty healthy participants (20 women, 20 men) were exposed to emotionally arousing and neutral pictures. Twenty-four hours later, 20 participants underwent a social stressor (speech and math tests), and 20 underwent a control reading task, both followed by a delayed free recall task. Cortisol responders to the stress condition (5 men and 1 woman) showed reduced memory retrieval for both neutral and emotionally arousing pictures. Men and women in the stress condition who did not produce a cortisol response showed increased retrieval of unpleasant pictures compared to controls. The results provide further evidence that cortisol is a primary effector in the stress-induced memory retrieval deficit. At the same time, stress can enhance memory retrieval performance, especially for emotional stimuli, when the cortisol response is absent.     

The effects of SES on infant and maternal diurnal salivary cortisol output

The present study directly compared diurnal salivary cortisol output and maternal-infant synchrony in low and high socio-economic status (SES) mother–infant dyads. Saliva cortisol samples were collected from 32 6–12-month-old infants and their mothers on the same day in the morning, afternoon and evening, and assayed for free cortisol concentration. Low-SES infants and mothers exhibited higher average salivary cortisol output, without dysregulation, compared to high-SES infants. Low-SES infants and mothers also showed reduced synchrony in cortisol output compared to high-SES infants and mothers. Results are discussed with respect to maternal sensitivity and early stress reduction interventions.     

Impaired memory retrieval correlates with individual differences in cortisol response but not autonomic response

Stress can enhance or impair memory performance. Both cortisol release and sympathetic nervous system responses have been implicated in these differential effects. Here we investigated how memory retrieval might be affected by stress-induced cortisol release, independently of sympathetic nervous system stress responses. Thirty-two healthy participants (16 women) learned emotionally arousing and neutral words. One hour later, half of the participants underwent a stressor (cold pressor test) and the other half, a control warm water exposure, both followed by a delayed free recall task. The stressed participants were split into those who did (responders, N = 8) and those who did not (nonresponders, N = 6) show a cortisol response. Both responders and nonresponders showed comparable sympathetic nervous system activity (skin conductance level) during the cold pressor. The cortisol responders recalled significantly fewer words compared to nonresponders, and compared to control participants; this effect was most pronounced for moderately arousing words (compared to highly arousing and neutral words). These results suggest that individual differences in cortisol reactivity affect memory retrieval performance, and help to explain the differential effects of stress on memory.     

Eyewitness Evidence Obtained with the Self‐Administered Interview© Is Unaffected by Stress

The Self‐Administered Interview© (SAI) serves to elicit eyewitness statements directly after the crime. Witnesses could still experience stress then. Because stress during retrieval produces memory‐impairing effects, this study sought to compare the SAI with free recall under stress. An interaction between stress and interview was expected such that the SAI would elicit more comprehensive accounts than free recall in the control, but not in the stress group. One hundred and twenty‐seven participants underwent a stress or control task. They witnessed a live staged crime and completed an SAI or a free recall. The SAI elicited a higher number of correct verifiable event details and a higher number of correct and incorrect perpetrator details than free recall. Accuracy rates were unaffected. Unexpectedly, despite causing moderate stress‐induced cortisol elevations, stress exposure did not influence memory performance and did not interact with interview type. Hence, the SAI can safely be used, when witnesses are moderately stressed.Copyright © 2015 John Wiley & Sons, Ltd.     

Acute stress impairs recognition for positive words--association with stress-induced cortisol secretion

Some studies suggest that stress-induced effects of cortisol on memory are modulated by the valence of the stimuli to be learned and retrieved. The present study investigated the effect of acute stress-induced cortisol secretion on acquisition and retrieval of pleasant, unpleasant and neutral words. Sixty healthy men were randomly assigned to one of the three experimental groups. Participants were either exposed to a standardized laboratory stressor (the Trier Social Stress Test) before learning a wordlist, or before retrieval, or were not stressed. Free recall and recognition were tested 24 h later. Free recall was not affected by stress exposure. For recognition, there was no main effect of the stressor, but a main effect of valence and a valence by group interaction emerged: recognition for positive words was significantly impaired when subjects were stressed before retrieval. In addition, a positive correlation between the cortisol response and errors of commission was found. The results suggest that acute stress impairs memory for positive stimuli and that stress-induced cortisol secretion interferes with accuracy of memory retrieval, i.e. the ability to discriminate true memories from false ones.     

Dating couples' attachment styles and patterns of cortisol reactivity and recovery in response to a relationship conflict

This study investigated theoretically predicted links between attachment style and a physiological indicator of stress, salivary cortisol levels, in 124 heterosexual dating couples. Cortisol was assessed at 7 points before and after an experimental conflict negotiation task, creating a trajectory of stress reactivity and recovery for each participant. Growth modeling of cortisol data tested hypotheses that (a) insecurely attached individuals show patterns of greater physiological stress reactions to interpersonal conflict than do securely attached individuals and (b) people with insecurely attached partners show patterns of greater stress in reaction to relationship conflict than those with securely attached partners. Hypothesis 1 was supported, but men and women differed in the type of insecure attachment that predicted stress trajectories. Hypothesis 2 was supported for men, but not for women. The discussion emphasizes the role of gender role norms and partner characteristics in understanding connections between adult attachment and patterns of cortisol responses to interpersonal stress.     

DNA methylation of NR3c1 in infancy: Associations between maternal caregiving and infant sex

Caregivers play a critical role in scaffolding infant stress reactivity and regulation, but the mechanisms by which this scaffolding occurs is unclear. Animal models strongly suggest that epigenetic processes, such as DNA methylation, are sensitive to caregiving behaviors and, in turn, offspring stress reactivity. We examined the direct effects of caregiving behaviors on DNA methylation in infants and infant stress reactivity. Infants and mothers (N = 128) were assessed during a free play when infants were 5 months old. Maternal responsiveness and appropriate touch were coded. and infant buccal epithelial cells were sampled to assess for DNA methylation of the glucocorticoid receptor gene, NR3c1 exon 1F. Infant cortisol reactivity was assessed in response to the still-face paradigm. Greater levels of maternal responsiveness and appropriate touch were related to less DNA methylation of specific regions in NR3c1 exon 1F, but only for females. There was no association with maternal responsiveness and appropriate touch or DNA methylation of NR3c1 exon 1F on prestress cortisol or cortisol reactivity. Our results are discussed in relation to programming models that implicate maternal care as an important factor in programing infant stress reactivity.     

Gender Specific Effect of Psychological Stress and Cortisol Reactivity on Adolescent Risk Taking

The purpose of this study was to evaluate how psychological stress, gender and cortisol response to stress relate to risk behavior among 132 14–18 year old adolescents. Participants completed a laboratory based risk task prior to and immediately after a computerized psychological stress task, and salivary cortisol was collected from pre-stress to 60 min following initial stress exposure. Results indicate that adolescent boys (n?=?59) and girls (n?=?73) demonstrate different patterns of risk taking (RT) in response to stress, such that boys evidenced an increase in RT following stress exposure, whereas girls evidenced a decrease in RT. In addition, a gender by cortisol interaction demonstrated that for boys, both a smaller total cortisol output (AUCg) and peak cortisol response to stress (PC) was associated with greater stress-induced RT. Both cortisol measures were unrelated to stress-induced RT among girls. Taken together, data suggest that among boys, a blunted cortisol response to stress underlies an increase in risk taking in the context of psychological stress. Further research with an additional behavioral stress task is needed prior to drawing conclusions regarding the relation between female gender, cortisol response to stress, and risk taking in the context of psychological stress.     

Examination stress as an ecological inducer of cortisol and psychological responses to stress in undergraduate students

The purpose of the present study was to investigate basic methodological issues related to the usage of an examination stress protocol in studies of psychoneuroendocrinology. In the present study, 57 undergraduate students served as participants. All subjects provided salivary samples and completed psychological inventories during a low examination stress period and again during a high examination stress period. Salivary samples were analyzed for cortisol. Three major findings were observed. First, the examination stress protocol proved to be an effective trigger of elevations in both psychological measures of stress and in cortisol levels. Second, sex differences were observed in cortisol levels, such that males showed an elevation in cortisol during the high examination stress session whereas females did not. Finally, no significant correlations were observed between elevations in psychological measures of stress and elevations in cortisol levels. These findings suggest that the examination stress protocol used in the present study effectively elevated both psychological stress and cortisol levels. Furthermore, these findings suggest that there are biological differences in how males and females respond to stress. Finally, no evidence was found to suggest a relationship between psychological and hormonal levels of stress. Together, these findings suggest the need to better define and consider the implications of both the specific measures of stress being used and individual differences in the subject samples in psychoendocrine studies.     

Chronic stress in the mother-infant dyad: Maternal hair cortisol,infant salivary cortisol and interactional synchrony

Stress physiology is shaped by early experience, with enduring effects on health. The relation of chronic maternal physiological stress, as indexed by hair cortisol, to infants’ stress systems and to mother-infant interaction quality has not been established. We examined maternal hair and salivary cortisol, six-month-old infants’ salivary cortisol, and mother-infant interaction in 121 mother-infant dyads. High maternal hair cortisol was related to higher infant average salivary cortisol concentration. Maternal hair cortisol and bedtime salivary cortisol were both uniquely related to infant bedtime salivary cortisol. Mothers with higher hair cortisol were more intrusive and had lower positive engagement synchrony with their infants. Maternal intrusiveness moderated the association of maternal hair cortisol and infant salivary cortisol, such that maternal hair and infant average salivary cortisol were related only when mothers were more intrusive. Maternal chronic physiological stress may upregulate infants’ developing stress systems, particularly in the context of lower mother-infant interaction quality.