Posttraining Electrical Stimulation of Vagal Afferents with Concomitant Vagal Efferent Inactivation Enhances Memory Storage Processes in the Rat

Peripherally administered or released substances that modulate memory storage, but do not freely enter the brain, may produce their effects on memory by activating peripheral receptors that send messages centrally through the vagus nerve. Indeed, vagus nerve stimulation enhances memory performance, although it is unclear whether this effect is due to the activation of vagal afferents or efferents. To eliminate the possible influence of descending fibers on memory storage processes, rats were implanted with cuff electrode/catheter systems along the left cervical vagus. Forty-eight hours following surgery, each animal received a 3.0-μl infusion (1.0 μl/min) of either lidocaine hydrochloride (75.0 mM) or isotonic saline below the point of stimulation. Animals were then trained 10 min later on an inhibitory-avoidance task with a 0.75-mA, 1.0-s foot shock. Sham stimulation or vagus nerve stimulation (0.5-ms biphasic pulses; 20.0 Hz; 30 s; 0.2, 0.4, or 0.8 mA) was administered immediately after training. Memory, tested 24 h later, was enhanced by stimulation whether descending vagus nerve fibers were inactivated or not. Both lidocaine- and saline-infused groups showed an intensity-dependent, inverted-U-shaped pattern of retention performance, with the greatest effect observed for 0.4 mA (U= 9,p< .05, andU= 7,p< .01, respectively). Additionally, animals that received lidocaine infusions, but no vagus nerve stimulation, showed impaired memory compared to the performance of saline-infused control animals (U= 11,p< .05). Together, these findings suggest that vagal afferents carry messages about peripheral states that lead to the modulation of memory storage and that the memory-enhancing effect produced by vagus nerve stimulation is not mediated via the activation of vagal efferents.     

A BEHAVIORAL MODEL OF INFANT SLEEP DISTURBANCE

Chronic sleep disturbance, such as bed refusal, sleep-onset delay, and night waking with crying, affects 15% to 35% of preschool children. Biological factors, particularly arousals associated with recurrent episodes of rapid-eye-movement sleep, render infants vulnerable to repeated awakenings. Parental failure to establish appropriate stimulus control of sleep-related behaviors and parent-mediated contingencies of reinforcement for sleep-incompatible behaviors may shape and maintain infant sleep disturbance. Treatment and prevention strategies are discussed, and research needs are identified.     

Longitudinal changes in term and preterm infant night wakings: The role of caregiver anxious-depression

Changes in infant night waking during the first year of life are associated with individual (e.g., prematurity) and family (e.g., caregiver psychopathology) factors. This study examined the association between infant night waking and caregiver anxious-depressive symptoms during the first year of life in preterm and term infants. We considered between-person differences and within-person changes in caregiver anxious-depressive symptoms in relation to changes in infant night waking from 2- to 9-months. Racially (30.0% Black, 60.4% White, 9.5% multiracial/other) and socioeconomically (40.0% below median household income) diverse caregivers (N = 445) of full term (n = 258) and preterm (n = 187) infants were recruited from hospitals and clinics in two midwestern states. Caregivers completed measures of anxious-depression and their infant's night waking at four sampling periods (2-, 4-, 6-, and 9-months). Infant night wakings declined from 2- to 9-months. Between-person differences were observed, such that caregivers with higher average anxious-depressive symptoms or infants born full term reported more night wakings. Within-person effects of caregiver anxious-depressive symptoms were not significant. Caregiver anxious-depression is closely associated with infant night wakings. By considering a caregiver's average severity of anxious-depression, healthcare providers can more effectively plan infant sleep interventions. If caregiver anxious-depressive symptoms are ameliorated, night wakings may also decrease.     

睡眠剥夺与购物后悔：来自大规模个体层面数据的证据

睡眠剥夺正在成为人们面临的一种普遍问题,但是已有研究很少将睡眠剥夺与消费者行为联系起来。本文采用真实购物情境下的大规模消费者个体层面数据(N=1625472),通过建立计量经济学模型来研究睡眠剥夺与购物后悔的关系。结果表明,睡眠剥夺显著地增加了消费者的购物后悔倾向,具体在行为上表现为增加了商品的退货概率和加快了商品的退货速度。此外,商品的价格正向调节了睡眠剥夺对购物后悔的影响,而促销优惠金额的比例则负向调节了睡眠剥夺对购物后悔的影响。     

Sleep as a mediator of the relationship between social class and health in higher education students

A substantial body of research indicates that higher education students from lower social class backgrounds tend to have poorer health than those from higher social class backgrounds. To investigate sleep as a potential mediator of this relationship, online survey responses of students from five large Australian universities, one Irish university and one large Australian technical college were analysed in three studies (Study 1 N = 628; Study 2 N = 376; Study 3 N = 446). The results revealed that sleep quality, sleep duration, sleep disturbances, pre-sleep worries and sleep schedule variability mediated the relationship between social class and physical and mental health. Sleep remained a significant mediator when controlling for related variables and other mediators. Thus, the findings suggest that sleep partly explains social class differences in health. We discuss the importance of addressing sleep issues among students from lower social class backgrounds.     

Associations between sleep variables and ostensibly paranormal experiences and paranormal beliefs: A scoping review

Night-time is a period of great significance for many people who report paranormal experiences. However, there is limited understanding of the associations between sleep variables and seemingly paranormal experiences and/or beliefs. The aim of this review is to improve our understanding of these associations while unifying a currently fragmented literature-base into a structured, practical review. In this pre-registered scoping review, we searched for relevant studies in MEDLINE (PubMed), PsycINFO (EBSCO), Web of Science and EMBASE using terms related to sleep and ostensibly paranormal experiences and beliefs. Forty-four studies met all inclusion criteria. All were cross-sectional and most investigated sleep paralysis and/or lucid dreaming in relation to ostensibly paranormal experiences and paranormal beliefs. Overall, there were positive associations between many sleep variables (including sleep paralysis, lucid dreams, nightmares, and hypnagogic hallucinations) and ostensibly paranormal experiences and paranormal beliefs (including those of ghosts, spirits, and near-death experiences). The findings of this review have potential clinical implications such as reducing misdiagnosis and treatment development and provide foundations for further research. Our findings also highlight the importance of understanding why so many people report ‘things that go bump in the night’.     

Attempted induction of signalled lucid dreaming by transcranial alternating current stimulation

Neurophysiological correlates of self-awareness during sleep (‘lucid dreaming’) remain unclear despite their importance for clarifying the neural underpinnings of consciousness. Transcranial direct (tDC) and alternating (tAC) current stimulation during sleep have been shown to increase dream self-awareness, but these studies’ methodological weaknesses prompted us to undertake additional study. tAC stimulation was associated with signal-verified and self-rated lucid dreams—but so was the sham procedure. Situational factors may be crucial to inducing self-awareness during sleep.     

Neural recruitment related to threat perception differs as a function of adolescent sleep

Detecting threat cues in the environment is an important aspect of social functioning. This is particularly true for adolescents as social threats become more salient and they navigate increasingly complex relationships outside of the family. Sleep relates to socioemotional processing throughout development, but the neurobiological relevance of sleep for threat perceptions in adolescence remains unknown. In the present study, 46 human adolescents (aged 14–18 years; 26 female) made judgments while undergoing a brain scan about whether unfamiliar, affectively neutral, computer‐generated faces were threatening. Prior to the scan, several indices of sleep were assessed nightly for two‐weeks using actigraphy. Sleep duration and poor sleep quality (defined as less efficiency, more awakenings, longer awakenings), factors influenced by biological and psychosocial changes during adolescence, elicited distinct neural activation patterns. Sleep duration was positively associated with activation in visual and face processing regions (occipital cortex, occipital fusiform gyrus), and this activation was linked to increased threat detection during the threat perception task. Sleep quality was negatively related to dorsolateral prefrontal cortex activation, which moderated the relation between reaction time (RT) and exposure to faces. Findings suggest reduced threat perception for adolescents with shorter sleep durations and more impulsive responding (as evinced by less consistent RT) for adolescents experiencing worse quality sleep. This study identifies an association between sleep and neural functioning relevant for socioemotional decision making during adolescence, a time when these systems undergo significant development.     

父母物质惩罚对儿童睡眠质量的影响：主观幸福感的中介作用及友谊质量的调节作用

摘 要：为探讨父母物质惩罚与儿童睡眠质量的关系及其作用机制,采用问卷法对438名小学生进行调查。结果发现：（1）父母物质惩罚与儿童主观幸福感、睡眠质量之间呈现显著相关;（2）物质惩罚既能直接预测儿童睡眠质量,也能通过主观幸福感的中介作用预测睡眠质量;（3）友谊质量能在物质惩罚对儿童睡眠质量的中介中起到调节,对高友谊质量的儿童来说,物质惩罚对幸福感的作用不显著。研究结果揭示了作为物质型教养行为之一的物质惩罚对儿童睡眠质量的影响及其作用机制,能为提高儿童的幸福感及睡眠质量提供有效启示。     

Night waking in 6-month-old infants and maternal depressive symptoms

Relations between night waking in infants and depressive symptoms in their mothers at 6 months postpartum were examined using the data from the National Institute for Child Health and Human Development Study of Early Child Care. Although more depressive symptoms were only weakly correlated with a higher frequency of infant waking, longer wake times, and more total time awake, the rate of clinically significant depression scores was about double in mothers of chronically waking infants in comparison with mothers whose infants did not awaken during the night. The value of comparing subgroups to elucidate relations identified through correlations is discussed.