Insights into sleep's role for insight: Studies with the number reduction task

In recent years, vibrant research has developed on “consolidation” during sleep: To what extent are newly experienced impressions reprocessed or even restructured during sleep? We used the number reduction task (NRT) to study if and how sleep does not only reiterate new experiences but may even lead to new insights. In the NRT, covert regularities may speed responses. This implicit acquisition of regularities may become explicitly conscious at some point, leading to a qualitative change in behavior which reflects this insight. By applying the NRT at two consecutive sessions separated by an interval, we investigated the role of sleep in this interval for attaining insight at the second session. In the first study, a night of sleep was shown to triple the number of participants attaining insight above the base rate of about 20%. In the second study, this hard core of 20% discoverers differed from other participants in their task-related EEG potentials from the very beginning already. In the third study, the additional role of sleep was specified as an effect of the deep-sleep phase of slow-wave sleep on participants who had implicitly acquired the covert regularity before sleep. It was in these participants that a specific increase of EEG during slow-wave sleep in the 10-12 Hz band was obtained. These results support the view that neuronal memory reprocessing during slow-wave sleep restructures task-related representations in the brain, and that such restructuring promotes the gain of explicit knowledge.     

Editorial to the special issue Neuronus

Did you visit the Neuronus conferences in the years 2012 and 2013 in Kraków? If not, then you certainly should have a close examination of this special issue including this introduction to at least have a glimpse of an idea of the highly interesting topics in the field of cognitive neuroscience that were presented at these conferences. If you were there, it is for sure a good choice to focus on this special issue as well, first to refresh your minds (we know our memories are far from perfect), but especially to see what happened with research of the presenters at these conferences.     

Spontaneously Hypertensive Rats: Possible Animal Model of Sleep-Related Movement Disorders

Clinical experience suggests that restless legs syndrome (RLS), periodic leg movement (PLM), and attention-deficit hyperactivity disorder (ADHD) may co-occur in both children and adults. The purpose of the present study was to provide an electrocorticography and electromyography evaluation of the spontaneously hypertensive rat (SHR) to investigate the potential of this rat strain as an animal model of RLS–PLM. Initial work focused on evaluating sleep patterns and limb movements during sleep in SHR, having normotensive Wistar rats (NWR) as control, followed by comparison of two treatments (pharmacological–dopaminergic agonist treatment and nonpharmacological–chronic physical exercise), known to be clinically beneficial for sleep-related movement disorders. The captured data strengthen the association between SHR and RLS–PLM, revealing a significant reduction on sleep efficiency and slow wave sleep and an increase on wakefulness and limb movements for the SHR group during the dark period, as compared to the NWR group, effects that have characteristics that are strikingly consistent with RLS–PLM. The pharmacological and nonpharmacological manipulations validated these results. The present findings suggest that the SHR may be a useful putative animal model to study sleep-related movement disorders mechanisms.     

A Review of Published Self-help Books for Panic Disorder

This brief review of 14 self-help books on panic disorder compares: target group, treatment time, included components, existence of structured exercises, and whether or not daily record-keeping is encouraged. Six of the books cover all components deemed necessary for a multimodal cognitive-behavioral treatment package, and five of these are recommended. The reviews are followed by a brief summary of published bibliotherapy studies in which a selection of the books has been used. The results of these studies suggest that bibliotherapy is effective, with an effect size ranging from d = 0.5 to d = 1.5.     

睡眠的同步EEG-fMRI研究述评

同步EEG-fMRI利用了脑电和功能磁共振在时空分辨率上的互补优势,为睡眠研究提供了多模态的无创手段.这使得睡眠的神经成像研究可以借助电生理方法进行睡眠分期和特殊脑电事件研究,为探讨不同意识状态下神经活动动态过程提供了条件.本评述从自发脑活动和睡眠中的知觉过程两方面介绍了目前该领域的最新进展,结合硬件构成、被试安全和数据质量等问题总结了同步记录应用于睡眠的优缺点.同步EEG-fMRI技术在睡眠研究中的应用对于阐明意识状态转换的神经机制具有深刻意义,并有可能为临床睡眠障碍的诊断和治疗提供全新的思路.     

Associations Between Psychological Factors and Nighttime/Daytime Symptomatology in Insomnia

Purpose: The aim of this study was to examine psychological factors in insomnia and the association between psychological mechanisms and nighttime and daytime symptoms. Methods: A cross-sectional examination in the general population was used. The study sample consisted of 1890 participants from the general population. The participants completed a survey on nighttime and daytime symptoms, health outcomes, and psychological factors. Results: Relative to poor and normal sleepers, the insomnia group had higher scores on worry, beliefs, physiologic arousal, monitoring/attentional bias, and safety behaviors than the other two groups, and the poor sleepers exhibited a similar pattern relative to the normal sleepers. High total wake time was associated with more worry, physiologic arousal, and safety behaviors (26.3% variance), low sleep restoration with more worry, unhelpful beliefs, and monitoring/attentional bias (28.2% variance), and low sleep quality with higher scores on all the psychological mechanisms (35.8% variance). Elevated daytime symptoms were related to more unhelpful beliefs and monitoring/attentional bias (44.3% variance). Conclusion: The findings indicate that psychological factors are linked to nighttime and daytime symptomatology in insomnia.     

Perseverative thoughts and subjective health complaints in adolescence: Mediating effects of perceived stress and negative affects

Stable tendency to perseverative thoughts such as trait rumination and worry can influence somatic health. The purpose of the study was to investigate the relationship between perseverative thoughts and somatic complaints, and the possible mediating effects of perceived stress, negative and positive affectivity in adolescence. Having an acute or a chronic condition was also assessed to be controlled for and to reveal their effects on symptom reporting. Three hundred and six adolescents from 7th to 12th grade with mean age of 16.33 (SD = 1.29) participated in the study. Mediation analysis suggested that impact of trait-like perseverative thoughts on complaints were mediated by perceived stress and negative affectivity. Having an acute condition had also an effect on symptom reporting through increased negative affectivity. Our results highlight that ruminations or worry as stable intrapersonal characteristics are relevant processes in health and can be potential targets in prevention programmes in adolescence.     

The coupling of short sleep duration and high sleep need predicts riskier decision making

Abstract

Objective: To examine how risk-related decision making might be associated with habitual sleep variables, including sleep variability, sleep duration and perceived sleep need in young adults cross-sectionally and longitudinally.

Design: 166 participants completed a 7-day protocol with sleep and risk-related decision-making measures at baseline (T1) and 12 months later (T2).

Results: Habitual short sleep duration (averaging < 6?h nightly) was identified in 11.0% in our sample. After controlling for baseline demographic factors and risk-taking measures, self-reported sleep need at T1 interacted with habitual short sleep in predicting risk taking at follow-up (F_8,139=9.575, adjusted R²=.431, p<.001). T1 greater perceived sleep need predicted more risk taking among short sleepers, but decreased risk taking among normal sleepers at T2. Variable sleep timing was cross-sectionally correlated with making more Risky choices at baseline and fewer Safe choices after loss at follow up.

Conclusions: Young adults with variable sleep timing and those with short sleep duration coupled with high perceived sleep need were more likely to take risks. The moderating effects of perceived sleep need suggest that individual differences may alter the impact of sleep loss and hence should be measured and accounted for in future studies.     

Sleep hygiene behaviours: An application of the theory of planned behaviour and the investigation of perceived autonomy support,past behaviour and response inhibition

This study investigated the sleep hygiene behaviour of university students within the framework of the Theory of Planned Behaviour (TPB [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179–211.]), and examined the predictive validity of additional variables including perceived autonomy support, past behaviour and response inhibition. A total of 257 undergraduate students from an Australian university were administered two online questionnaires at two time points. At time 1, participants completed the TPB questionnaire and the Go/NoGo task as a measure of response inhibition. A week later at time 2, participants completed a questionnaire measuring the performance of sleep hygiene behaviours. Multiple and hierarchical regression analyses showed that the TPB model significantly predicted intention and behaviour. Although intention and perceived behavioural control were statistically significant in predicting behaviour, past behaviour and response inhibition accounted for more variance when added to the TPB model. Subjective norm was found to be the strongest predictor of intention implying the importance of normative influences in sleep hygiene behaviours. Response inhibition was the strongest predictor of behaviour, reinforcing the argument that the performance of health protective behaviours requires self-regulatory ability. Therefore, interventions should be targeted at enhancing self-regulatory capacity.