Stronger cortisol response to acute psychosocial stress is correlated with larger decrease in temporal sensitivity

Effect of Acute Psychological Stress on Speed Perception: An Event-Related Potential Study

The present study tested the intrinsic ERP features of the effects of acute psychological stress on speed perception. A mental arithmetic task was used to induce acute psychological stress, and the light spot task was used to evaluate speed perception. Compared with judgments in the constant speed and uniform acceleration motion, judgments in the uniform deceleration motion were made more quickly and with higher accuracy; attention control was higher and peaked later; and there was longer N2 peak latency, larger N2 peak amplitude, and lower mean amplitude of the late negative slow wave (SW). Under stress, the reaction time was significantly shorter. The N2 peak amplitude and SW mean amplitude were significantly higher, attention control was higher and appeared earlier, and there was a greater investment of cognitive resources. The type of movement and evoked stress also interacted to predict behavioral and ERP measures. Under acute stress, judgments made in the uniform deceleration motion condition elicited lower N2 peak latency, higher attention control, and later peak attention. The results suggest that judgments of the speed of decelerating motion require a lower investment of cognitive resources than judgments of other kinds of motion, especially under acute stress. These findings are best interpreted in terms of the interaction of arousal and attention.

A meta-analysis of salivary cortisol responses in the Trier Social Stress Test to evaluate the effects of speech topics, sex, and sample size

Background

The Trier Social Stress Test (TSST) is one of the most widely used laboratory-based psychological stress paradigms. Previous studies have shown that males have a more robust cortisol response than females in the TSST. However, the effects of sample size, speech topic, and interaction between sex and speech topic on cortisol responses in TSST remain elusive. Our goal was to evaluate these influencing factors in the TSST using salivary cortisol reactivity as an objective measure.

Methods

We collected TSST research articles in Web of Science, PubMed, PsycNet, and CNKI. We only included TSST studies that had measures of salivary cortisol both before and after task completion. A total of 65 articles involving 76 sub-studies met our inclusion criteria, with a total of 5171 participants (2040 females and 3131 males). The effects of sample sizes were assessed to determine if results of studies with various sample sizes were stable. We performed multivariate meta-regression to determine the effects of speech topic, sex, and the interaction between sex and speech topic after controlling their confounding effects. Subgroup analysis of sex was conducted to detect inter-group differences. We further evaluated the baseline and peak salivary cortisol concentrations for males and females independently to detect the sources of sex differences.

Results

The average effect size (i.e., Cohen's d) of salivary cortisol reactivity was 0.93, 95% CI = 0.82 to 1.04, p < .001. The small studies produced larger variations in the reported effect sizes than the large-sample studies (r = -0.24, p = .041). A sample size of 40 was necessary to provide sufficient statistical power to detect significant changes of salivary cortisol in TSST. Speech topics, sex, and sex-speech topic interaction could predict salivary cortisol responses (F(df1 = 3, df2 = 72) = 11.98, p < .001) and explained 42.68% of the total experimental variation. Sex was the only significant contributing factor (p < .00025) in the regression model. Salivary cortisol responses in males were significantly higher than in females (Q_B = 42.89, df = 1, p < .001). Further, significant differences between males and females were detected at baseline (t = -2.03, df = 74, p = .046) and peak (t = -4.96, df = 74, p < .001).

Conclusions

The TSST effectively induces stress response as measured by salivary cortisol change. Forty samples is the minimum sample size for detecting the robust salivary cortisol responses. We confirmed that males have more robust salivary cortisol reactivity than females in TSST. Speech topics that we tested did not significantly contribute to differences in salivary cortisol responses. No significant interaction between sex and speech topic on salivary cortisol responses was detected.

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Forty samples is the minimum for detecting robust salivary cortisol responses.

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The speech topics tested did not significantly alter salivary cortisol responses.

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Males have higher salivary cortisol responses than females in the TSST.

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Males had higher salivary cortisol levels than females in the TSST at both baseline and peak.

Males with low risk-taking propensity overestimate risk under acute psychological stress

Arousing research has investigated stressed individuals' decision biases, but whether and how stress and individual traits interact to impact the underlying decision-making process is unknown. Here, we aim to explore the effect of acute stress on the interaction between the objective level of risk and subjective risk preference (i.e. risk-taking propensity). Eighty-three healthy males participated in the study. We adopted the Trier Social Stress Test (TSST) to induce acute psychological stress and categorized participants into the high or low risk-taking propensity (HRP/LRP) group according to their traits in daily life. The Balloon Analogue Risk Task (BART) was applied to measure their feedback processing in a risky decision task, while behavioral indexes and EEG signals were recorded. The results showed that stressful participants pumped fewer times than the controls, especially for the LRP under stress, indicating that they were more willing to avoid taking risks. Compared with the stressed HRP group, the stressed LRP showed higher salivary cortisol responses and a more positive FRN following positive feedback in higher risk levels. It implies that acute psychological stress leads the LRP to overestimate the risk probability and become more cautious in the sequential processing of risk. These findings highlight the role of the feedback process and individual traits in risky decision-making under stress.

Formalin-induced pain prolongs sub- to supra-second time estimation in rats

Background

Temporal estimation can be influenced by pain, which is a complex psychological and physiological phenomenon. However, the time range in which perception is most sensitive to pain remains unclear.

Methods

In the present study, we explored the effects of acute inflammatory pain on time perception in the sub- to supra-second (0.6–2.4-s) and supra-second (2–8-s) ranges in rats. Plantar formalin injection was used to induce acute inflammatory pain, and a temporal bisection task was used to measure time perception. Task test sessions were held for five consecutive days (one per day): the day before injection (baseline), immediately after injection, and the three post-injection days. The point of subjective equality (PSE, which reflects the subjective duration) and Weber fraction (which reflects temporal sensitivity) were calculated and analysed.

Results

In the 0.6–2.4-s range, the PSE was significantly lower, indicating prolonged subjective duration, in the formalin group relative to the saline group (p = 0.049) immediately after injection. Formalin-induced pain also tended to lengthened time perception in the 0.6–2.4-s range on post-injection days 2 (p = 0.06) and 3 (p = 0.054). In the 2–8-s range, formalin injection did not affect the PSE or Weber fraction.

Conclusions

The enhanced effect of pain on temporal perception in the sub- to supra-second range is observed in this study and this effect is attenuated with the prolongation of estimated time, even in rats.

A systematic review of the Trier Social Stress Test methodology: Issues in promoting study comparison and replicable research

Since its development in 1993, the Trier Social Stress Test (TSST) has been used widely as a psychosocial stress paradigm to activate the sympathetic nervous system and hypothalamic-pituitary-adrenal axis (HPAA) stress systems, stimulating physiological functions (e.g. heart rate) and cortisol secretion. Several methodological variations introduced over the years have led the scientific community to question replication between studies. In this systematic review, we used the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) to synthesize procedure-related data available about the TSST protocol to highlight commonalities and differences across studies. We noted significant discrepancies across studies in how researchers applied the TSST protocol. In particular, we highlight variations in testing procedures (e.g., number of judges, initial number in the arithmetic task, time of the collected saliva samples for cortisol) and discuss possible misinterpretation in comparing findings from studies failing to control for variables or using a modified version from the original protocol. Further, we recommend that researchers use a standardized background questionnaire when using the TSST to identify factors that may influence physiological measurements in tandem with a summary of this review as a protocol guide. More systematic implementation and detailed reporting of TSST methodology will promote study replication, optimize comparison of findings, and foster an informed understanding of factors affecting responses to social stressors in healthy people and those with pathological conditions.

Stress and prospective memory: What is the role of cortisol?

Studies investigating effects of acute stress on Prospective Memory (PM) so far yielded heterogeneous findings. Although results were commonly attributed to stress-induced changes in cortisol, past research did not disentangle effects of cortisol from the effects of sympathetic nervous system (SNS) activation and cognitive reappraisal. The present study therefore aimed at investigating the mere effect of cortisol on PM tasks that differently involve prefrontal brain regions (nonfocal vs. focal PM tasks) via a placebo-controlled oral pharmacological intake of 10 mg hydrocortisone mimicking physiological responses to stress. Contrary to our prediction, enhanced levels of cortisol did not affect PM accuracy and monitoring costs, neither for the focal nor the nonfocal PM tasks. These results suggest that changes of cortisol levels do not underlie potential stress effects on PM. Further exploratory results revealed that PM performance was higher in the 3 pm than in the 1 pm placebo group. This means that PM performance, independently of effects of cortisol, seem to vary throughout the day.