Age attenuates noise and increases symmetry of head movements during sleep resting-state fMRI in healthy neonates,infants, and toddlers

Newborns produce spontaneous movements during sleep that are functionally important for their future development. This nuance has been previously studied using animal models and more recently using movement data from sleep resting-state fMRI (rs-fMRI) scans. Age-related trajectory of statistical features of spontaneous movements of the head is under-examined. This study quantitatively mapped a developmental trajectory of spontaneous head movements during an rs-fMRI scan acquired during natural sleep in 91 datasets from healthy children from ∼birth to 3 years old, using the Open Science Infancy Research upcycling protocol. The youngest participants studied, 2–3 week-old neonates, showed increased noise-to-signal levels as well as lower symmetry features of their movements; noise-to-signal levels were attenuated and symmetry was increased in the older infants and toddlers (all Spearman's rank-order correlations, P < 0.05). Thus, statistical features of spontaneous head movements become more symmetrical and less noisy from birth to ∼3 years in children. Because spontaneous movements during sleep in early life may trigger new neuronal activity in the cortex, the key outstanding question for in vivo, non-invasive neuroimaging studies in young children is not “How can we correct head movement better?” but rather: How can we represent all important sources of neuronal activity that shape functional connections in the still-developing human central nervous system?     

Facebook use and sleep quality: Light interacts with socially induced alertness

It has been demonstrated that the use of social networking sites late at night can lead to sleep‐related problems that extend into the next day. A common explanation is that the light emitted from screens is disrupting the users’ circadian rhythms. An alternative explanation is that the social cognition inherent in the use of social networking sites is responsible. Here, the two factors were looked at together. Participants used Facebook on iPad tablets before sleep. This was done on different nights with two lighting conditions and with two levels of content. In the ‘light’ condition, blue wavelength light was manipulated so that it was either full wavelength or blue light filtered. In the ‘alertness’ condition, the personal significance of the content was changed from personally relevant to irrelevant. A modified version of the Pittsburgh Sleep Quality Index was used to measure sleep‐related problems. No evidence was found that simply filtering blue light or simply removing relevant content improved sleep quality. However, the two factors interacted. The results suggest that the light emitted from screens can affect sleep quality under some conditions but this is behaviourally irrelevant in the context of normal Facebook usage.     

An assessment of sleep architecture as a function of degree of handedness in college women using a home sleep monitor

The present study examined sleep architecture as a function of handedness in a population of undergraduate college women using a home sleep monitor. Compared to strongly handed individuals, participants with a tendency toward mixed-handedness had a shorter sleep latency and spent a greater percentage of their sleep period asleep and less awake. Increasing mixed-handedness was also associated with increased NREM; strong-handedness was associated with increased REM. Results are placed in a neurophysiological framework wherein corpus callosum mediated differences in interhemispheric interaction during Wake, REM, and NREM on the one hand, and individual differences in corpus callosum morphology and hemispheric communication as a function of handedness on the other, interact to result in handedness differences in sleep architecture.     

Romantic relationships of young people with childhood and adolescent onset antisocial behavior problems

Using prospective longitudinal data from the Christchurch Health and Development Study, this paper examines the extent to which early onset, life course persistent and adolescent limited antisocial behavior problems place young people at risk of violent and unsatisfactory romantic relationships in early adulthood. Results revealed the presence of clear linear associations between the developmental timing of antisocial behavior and later partnership risks, with these risks including partner violence perpetration and victimization, interpartner conflict, and increased ambivalence about the relationship. Young people with childhood onset antisocial behavior problems reported higher rates of partnership difficulties than young people with adolescent limited antisocial behavior problems, while those with adolescent limited antisocial behavior reported higher levels of partnership difficulties than young people without a history of antisocial behavior problems. These associations persisted even after extensive control for a range of social, family, and individual factors that were correlated with the timing of antisocial behavior. Results highlight the importance of distinguishing between early and late onset antisocial behavior, and provide further support for existing life course models of the development of antisocial behavior problems in children and adolescents.     

Nighttime sleep and physical activity in 6-7 month-old infants

This study examined associations between objectively-measured nighttime sleep duration and physical activity in a sample of 6–7 month-old infants (N=93). The study also investigated relationships between infant sleep and demographic and environmental characteristics. Cross-sectional relationships were assessed using linear regression analyses. Nighttime sleep duration was positively associated with physical activity levels. Nighttime sleep duration was greater when infants had a consistent bedtime, slept in a separate room, were male, and had mothers who reported having a college education or greater. These findings can inform the development of interventions that aim to improve infant sleep.     

Physical activity is positively associated with college students' positive affect regardless of stressful life events during the COVID-19 pandemic

The study was designed to determine associations between physical activity (PA) and affect before and during COVID-19 stay-at-home orders and how change in PA predicted change in affect during this time. Before and during COVID-19 stay-at-home orders, college students (n = 107) completed assessments of PA, positive and negative affect, sleep quality, food insecurity, and stressful life events (during stay-at-home order only). Total minutes of PA was positively associated with positive affect before (B = 0.01, p < 0.01) and during (B = 0.01, p = 0.01) COVID-19 stay-at-home orders. Change in minutes of PA was positively associated with change in positive affect (B = 0.01, p = 0.01). Associations between PA and positive affect were not moderated by stressful life events. PA only predicted negative affect before COVID-19 stay-at-home orders (B = −0.003, p = 0.04). PA appears to enhance positive affect during a global pandemic. Findings have implications for PA as a tool for maintaining or enhancing mental health during a time of trauma and uncertainty.     

The relationship between sleep and working memory in children with neurological conditions

The objective of this study is to investigate whether sleep problems might account for the increased working memory deficits observed in school-aged children with neurological conditions. A novel, transdiagnostic approach to the investigation was chosen, and sleep is treated as a process that can potentially account for working memory difficulties across a range of neurological conditions. Prevalence estimates of sleep problems are also examined. Archival data of 237 children aged 6 to 11 years were collected from a Western Australian statewide neuropsychological service for the period 26 July 2011 to 14 January 2014. Measures of parent-reported sleep quality, snoring, and daytime sleepiness were obtained, in addition to objective measures of verbal and spatial working memory, storage capacity, and processing speed. The results of the data analysis reveal that over one third of participants reported having clinically-significant levels of sleep problems and that poor sleep quality is significantly associated with verbal working memory difficulties. This association remains after partialling out the variance contributed to performance by storage capacity and processing speed, suggesting that sleep is impacting upon an executive component of working memory. No other significant associations are observed. The results suggest that poor sleep quality is associated with an executive component of verbal (rather than spatial) working memory in children with neurological conditions. This has implications for the biological mechanisms thought to underlie the relationship between sleep and cognition in children. The results also demonstrate the clinical utility of a transdiagnostic approach when investigating sleep and cognition in children with neurological conditions.     

The relationship between sleep problems and working memory in children born very preterm

In two studies, the relationship between sleep and working memory performance was investigated in children born very preterm (i.e., gestation less than 32 weeks) and the possible mechanisms underlying this relationship. In Study 1, parent-reported measures of snoring, night-time sleep quality, and daytime sleepiness were collected on 89 children born very preterm aged 6 to 7 years. The children completed a verbal working memory task, as well as measures of processing speed and verbal storage capacity. Night-time sleep quality was found to be associated with verbal working memory performance over and above the variance associated with individual differences in processing speed and storage capacity, suggesting that poor sleep may have an impact on the executive component of working memory. Snoring and daytime sleepiness were not found to be associated with working memory performance. Study 2 introduced a direct measure of executive functioning and examined whether sleep problems would differentially impact the executive functioning of children born very preterm relative to children born to term. Parent-reported sleep problems were collected on 43 children born very preterm and 48 children born to term (aged 6 to 9 years). Problematic sleep was found to adversely impact executive functioning in the very preterm group, while no effect of sleep was found in the control group. These findings implicate executive dysfunction as a possible mechanism by which problematic sleep adversely impacts upon cognition in children born very preterm, and suggest that sleep problems can increase the cognitive vulnerability already experienced by many of these children.     

What is unconsciousness in a fly or a worm? A review of general anesthesia in different animal models

All animals are rendered unresponsive by general anesthetics. In humans, this is observed as a succession of endpoints from memory loss to unconsciousness to immobility. Across animals, anesthesia endpoints such as loss of responsiveness or immobility appear to require significantly different drug concentrations. A closer examination in key model organisms such as the mouse, fly, or the worm, uncovers a trend: more complex behaviors, either requiring several sub-behaviors, or multiple neural circuits working together, are more sensitive to volatile general anesthetics. This trend is also evident when measuring neural correlates of general anesthesia. Here, we review this complexity hypothesis in humans and model organisms, and attempt to reconcile these findings with the more recent view that general anesthetics potentiate endogenous sleep pathways in most animals. Finally, we propose a presynaptic mechanism, and thus an explanation for how these drugs might compromise a succession of brain functions of increasing complexity.     

Sleep disruption and motor development: Does pulling-to-stand impacts sleep–wake regulation?

During the second half of the 1st year, periods of increased sleep disruption have been documented alongside overall improvement in sleep–wake regulation. The objective of the present research was to test if pulling-to-stand (PTS), a milestone typically achieved during the latter part of the 1st year, co-occurs with a period of disrupted sleep. In a longitudinal design, 20 healthy infants were followed-up, from 7 to 11–12 months, at 3-week intervals. Each measurement consisted of filmed motor observations and sleep recordings (actigraphy), both conducted at home. It was found that among early achievers of PTS (by 8 months), the milestone was time-linked to a period of disrupted sleep. The results point to the significance of timing in the interplay between domains of development, and highlight the importance of considering both chronological and developmental metrics in studying changes in sleep–wake regulation.