Justifications for bullying among Japanese schoolchildren

The present research investigated the justifications for bullying as a function of the various roles that children assume in bullying. Contrary to expectations, most children judged bullying to be right or at least permitted regardless of their role in the episode. However, children with different types of involvement in bullying showed different justification strategies. In particular, bullies were more likely to blame the victims than were children assuming other roles. Gender differences were found in the justifications provided. Boys were more likely to blame the victims, whereas girls were more likely to engage in denial of injury. These results support the notion that justifications for bullying function to sustain bullying.     

A simple computational algorithm of model-based choice preference

A broadly used computational framework posits that two learning systems operate in parallel during the learning of choice preferences—namely, the model-free and model-based reinforcement-learning systems. In this study, we examined another possibility, through which model-free learning is the basic system and model-based information is its modulator. Accordingly, we proposed several modified versions of a temporal-difference learning model to explain the choice-learning process. Using the two-stage decision task developed by Daw, Gershman, Seymour, Dayan, and Dolan (2011), we compared their original computational model, which assumes a parallel learning process, and our proposed models, which assume a sequential learning process. Choice data from 23 participants showed a better fit with the proposed models. More specifically, the proposed eligibility adjustment model, which assumes that the environmental model can weight the degree of the eligibility trace, can explain choices better under both model-free and model-based controls and has a simpler computational algorithm than the original model. In addition, the forgetting learning model and its variation, which assume changes in the values of unchosen actions, substantially improved the fits to the data. Overall, we show that a hybrid computational model best fits the data. The parameters used in this model succeed in capturing individual tendencies with respect to both model use in learning and exploration behavior. This computational model provides novel insights into learning with interacting model-free and model-based components.     

Long-lasting effects of inescapable-predator stress on brain tryptophan metabolism and the behavior of juvenile mice

The kynurenine (KYN) pathway, which is initiated by indoleamine 2,3-dioxygenase, is the main tryptophan (TRP) metabolic pathway. It shares TRP with the serotonin (5-HT) pathway. We investigated the influence of inescapable-predator (rat) stress on behavior and brain TRP metabolism in mice. Male ICR mice (4W) were exposed to 20-min inescapable-predator stress. Behavior on an elevated plus-maze, and TRP, KYN, and 5-HT levels in the prefrontal cortex, hippocampus, amygdala, and dorsal raphe nuclei were measured 1 and 4 weeks after stress exposure. Predator stress increased the number of open-arm entries (NOA) 4 weeks after stress exposure without altering the number of closed-arm entries (NCA). Thus, the open/closed-arm entry ratio (NOA/NCA) increased after stress exposure. Predator stress increased KYN levels in the prefrontal cortex (until 4 weeks after stress exposure) and dorsal raphe nuclei (for 1 week after stress exposure), decreased 5-HT levels in all brain regions (until 4 weeks after stress exposure). Thus, predator stress increased the KYN/5-HT ratio in all regions, in particular in the prefrontal cortex and hippocampus until 4 weeks after stress exposure. Predator stress shifted the balance between the KYN and 5-HT pathways to the KYN pathway, and induced behavioral disinhibition.     

Feeling bad about screwing up: emotion regulation and action monitoring in the anterior cingulate cortex

This study examined neural features of emotional responses to errors. We specifically examined whether directed emotion regulation of negative emotion associated with error modulates action-monitoring functions of anterior cingulate cortex, including conflict monitoring, error processing, and error prevention. Seventeen healthy adults performed a continuous performance task during assessment by fMRI. In each block, participants were asked either to increase or decrease their negative emotional responses or to react naturally after error commission. Emotion regulation instructions were associated with modulation of rostral and dorsal anterior activity and of their effective connectivity following errors and conflict. Cingulate activity and connectivity predicted subsequent errors. These data may suggest that responses to errors are affected by emotion and that aspects of emotion and cognition are inextricably linked, even during a nominally cognitive task.     

Influence of attention manipulation on emotion and autonomic responses

Psychopathologies such as depression and anxiety have been associated with self-consciousness, a trait focusing on the self in terms of emotions and social images. A technique designed to shift attention away from the self tends to reduce anxiety, so the present purpose was to assess the effect of self body-state information on an individual's emotional and autonomic activity. 24 undergraduate and graduate students (10 men and 14 women), ages 19 to 27 years (M = 22.1, SD = 2.5), were recruited as subjects. Focusing on body-state during an anxiety-inducing situation led to an increase of low to high frequency ratio of heart-rate variability which reflected cardiac sympathovagal balance. That is, attending to one's own bodily states enhanced relative sympathetic activity compared to parasympathetic activity, which can be interpreted as one of the physiological emotional responses elicited by anxiety.     

Coping orientation and psychological distress in healthcare professionals: The utility of appraising coping acceptability

The purpose of this study was to examine interaction effects of healthcare professionals' coping orientation (i.e., engagement versus disengagement) and appraisal of coping acceptability (ACA) on psychological distress, taking into account the individuals' job specificity and the psychological climate in their work environment. A cross‐sectional survey was conducted, and Japanese healthcare professionals (N = 189; 117 female; mean age: 40.1 ± 11.2 years) reported the coping strategies that they employed for task‐related or interpersonal stressors, their cognitive appraisal of the stressors, their ACA, and the psychological distress evoked by the stressors. The results showed that adding consideration of the ACA to the variable of coping orientation significantly improved predictions of psychological distress for both task and interpersonal stressors. There was no significant interaction between the coping orientation and the use of coping strategies that incorporated the ACA. These results suggest that considering the ACA, in addition to the coping orientation, would be useful for understanding individual differences in the mediators of healthcare professionals' coping in stressful situations.     

Anxiety and heart rate variability before sleep indicate chronic stress in students

The purpose of the present study was to investigate the effect of chronic stress on the first-night effect in terms of autonomic nervous system activity and anxiety. Participants (N = 11; M age = 20.3 yr., SD = 0.47) included six with high stress (High stress group) and five with low stress (Low stress group), for whom all EEG data were available from three consecutive nights. Heart rate variability was calculated using the MemCalc method. The ratio of low to high frequency of heart rate variability before sleep onset in the High stress group on the first night indicated significantly higher activities than the ratio before sleep onset in the Low stress group. No significant difference in sleep latency was found between the two groups. However, the High stress group was more aware of anxiety than was the Low stress group, and the former estimated more subjective difficulty in falling asleep. These results suggest that measuring LF/HF before sleep may constitute a new way to assess chronic stress.     

Changes in brain tryptophan metabolism elicited by ageing, social environment, and psychological stress in mice

The kynurenine (KYN) pathway, which is initiated by indoleamine 2,3-dioxygenase (IDO), is a tryptophan (TRP) metabolic pathway. It shares TRP with the serotonin (5-hydroxytryptamine, 5-HT) pathway. In major depression, activation of the KYN pathway may deplete 5-HT. In the present study we investigated the influence of various risk factors for depression, such as ageing, social isolation and psychological stress, on TRP metabolism. Male ICR mice (postnatal day, PND, 21) were divided into two housing conditions, isolation and group housing, reared for 4 weeks (young adult) or 5 months (adult) and exposed to novelty stress. We measured TRP, KYN and 5-HT contents in the prefrontal cortex, hippocampus, amygdala and dorsal raphe nuclei to investigate the balance between the KYN and 5-HT pathways. Ageing decreased TRP and KYN and increased 5-HT. Thus, ageing shifted the balance to the latter. In the younger group, social isolation decreased TRP and KYN and increased the 5-HT/TRP ratio, whereas novelty stress increased TRP and KYN and decreased the 5-HT/TRP ratio. Thus, social isolation shifted the balance to the latter, whereas novelty stress shifted it to the former. In the older group, these effects were restricted to specific brain regions. Ageing and social isolation counteracted novelty stress effects on TRP metabolism.     

Is aversive learning a marker of risk for anxiety disorders in children?

Aversive conditioning and extinction were evaluated in children with anxiety disorders (n=23), at-risk for anxiety disorders (n=15), and controls (n=11). Participants underwent 16 trials of discriminative conditioning of two geometric figures, with (CS+) or without (CS-) an aversive tone (US), followed by 8 extinction trials (4 CS+, 4 CS-), and 8 extinction re-test trials averaging 2 weeks later. Skin conductance responses and verbal ratings of valence and arousal to the CS+/CS- stimuli were measured. Anxiety disordered children showed larger anticipatory and unconditional skin conductance responses across conditioning, and larger orienting and anticipatory skin conductance responses across extinction and extinction re-test, all to the CS+ and CS-, relative to controls. At-risk children showed larger unconditional responses during conditioning, larger orienting responses during the first block of extinction, and larger anticipatory responses during extinction re-test, all to the CS+ and CS-, relative to controls. Also, anxiety disordered children rated the CS+ as more unpleasant than the other groups. Elevated skin conductance responses to signals of threat (CS+) and signals of safety (CS-; CS+ during extinction) are discussed as features of manifestation of and risk for anxiety in children, compared to the specificity of valence judgments to the manifestation of anxiety.     

Effects of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance: comparison of horizontal and 6 degrees head-down bed rest

This study examined the effect of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance. Each of 7 volunteers were maintained for 3 days of head-down and horizontal bed rest in a counter-balanced design. Assessment measures were polysomnographic recordings on the first night and performance on psychophysiological tasks on the second day involving subjective and objective vigilance, P300, simple reaction time tasks, and dual performance tasks. No clear difference in sleep structure was observed between the head-down and horizontal conditions, except for a slight decrease in Stage 4 for head-down. Both subjective and objective daytime vigilance, P300, and the simple RT task showed no statistical difference, although tracking performance on the dual task showed deterioration at 10:00 for the head-down condition. These results suggest that nocturnal sleep, daytime vigilance, and psychophysiological functions were not disturbed in head-down sleep conditions, although there was a mild deterioration of higher attentional function in the morning.