Highlights This cross-sectional study was conducted during the initial outbreak of the COVID-19 epidemic. Higher level of perceived stress due to the COVID-19 epidemic was related with more emotional distress. Stress related increase in emotional distress is mediated by boredom proneness. Positive coping strategies act as a buffer in alleviating emotional distress under stress.

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Highlights This longitudinal study was implemented at two timepoints, i.e., during the peak and the remission of the COVID-19 pandemic. Fear significantly decreased over time, while depression level significantly increased during the second wave compared to the first wave of the survey. Younger age, lower-income, increased level of perceived stress, and current quarantine experience were significant predictors of depression escalation. The use of negative coping strategy plays a potential intermediating role in the stress-related increase in hostility, while social support acts as a buffer in hostility in the general population under high stress.

Motivation can be generated intrinsically or extrinsically, and both kinds of motivation show similar facilitatory effects on memory. However, effects of extrinsic and intrinsic motivation on memory formation have not been studied in combination and thus, it is unknown whether they interact and how such interplay is neurally implemented. In the present study, both extrinsic monetary reward and intrinsic curiosity enhanced memory performance, without evidence for an interaction. Functional magnetic resonance imaging revealed that curiosity-driven activity in the ventral striatal reward network appears to work cooperatively with the fronto-parietal attention network, while enhancing memory formation. In contrast, the monetary reward-modulated subsequent memory effect revealed deactivation in parietal midline regions. Thus, curiosity might enhance memory performance by allocation of attentional resources and reward-related processes; while, monetary reward does so by suppression of task-irrelevant processing.

Academic examination is a major stressor for students in China. Investigation of stress-sensitive endocrine responses to major examination stress serves as a good model of naturalistic chronic psychological stress in an otherwise healthy population. The cortisol awakening response (CAR) is an endocrine marker of the hypothalamic-pituitary-adrenocortical (HPA) axis in response to stress. However, it remains unknown how chronic examination stress impacts the CAR in a young healthy population To exclude the influence of sex effects on hormone level, the CAR and psychological stress responses were assessed on two consecutive workdays in 42 male participants during their preparations for the Chinese National Postgraduate Entrance Exam (NPEE) and 21 non-exam, age-matched male comparisons. On each day, four saliva samples were collected immediately after awakening, 15 minutes, 30 minutes and 60 minutes after awakening. The waking level (S1), the increase within 30 minutes after awakening (R30), the area under the curve with respect to ground (AUCg), and the area under the curve with respect to increase (AUCi) were used to quantify the CAR. Psychological stress and anxiety were assessed by the Perceived Stress Scale and the Spielberger State-Trait Anxiety Inventory, respectively. Male participants in the exam group had greater perceived stress and anxiety scores relatibe to the non-exam group. Both R30 and AUCi in the exam group were significantly lower than the comparison group and this effect was most pronounced for participants with high levels of perceived stress in the exam group. Perceived stress and anxiety levels were negatively correlated with both R30 and AUCi. Chronic examination stress can lead to the decrease of CAR in healthy young men, possibly due to reduced HPA axis activity under long-term sustained stress.

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This study examined the neural dynamics of working memory (WM) processing under long-term stress. Forty participants who had been exposed to a long period of major exam preparation (six months) and twenty-one control participants performed a numerical n-back task (n = 1, 2) while electroencephalograms were recorded. Psychological and endocrinal measurements confirmed significantly higher levels of long-term stress for participants in the exam group. The exam group showed significantly increased P2 amplitude in the frontal-central sites in the 1-back and 2-back conditions, whereas other ERP components, including the P1, N1 and P3 and behavioral performance, were unchanged. Notably, the P2 effect was most pronounced in participants in the exam group who reported perceiving high levels of stress. The perceived stress scores positively correlated with the P2 amplitude in the 1-back and 2-back conditions. These results suggest that long-term stress has an impact on attention and the initiation of the updating process in WM.

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