Multi-method exploration of the relationship between sleep and infant neurocognitive development

The first year of life is a time of numerous developmental milestones. At the same time an infant’s sleep under goes many fundamental changes. Research has shown that sleep can impact aspects of development; however, findings are mixed, often fail to include objective measures of both development and sleep, and longitudinal studies are missing. This project uses a multi-method approach to exploring the relationship between sleep and neurocognitive development in the first year of life. For this purpose, longitudinal and cross-sectional experimental designs were combined with a multitude of objective and subjective methods (such as electroencephalography(EEG), actigraphy, eye-tracking, near-infrared spectroscopy(NIRS), parent-report questionnaires),and analysis approaches (cluster analysis, mixed modelling, and functional connectivity analysis). Key insights from the longitudinal study showed that cross-method agreement between different sleep measures varied depending on sleep parameters, infant age, and maternal stress. Moreover, sleep measurement choice can influence how the relationship between sleep and development is described. Associations with behavioural and parent-report measures of infant development were fragmented. However, a clearer cross-method consistent picture emerged with regard to brain measures that highlighted the importance of studying sleep fragmentation. The study also underscored the need to study the relationship between sleep and development continuously as there was evidence for age-related changes in the association between sleep and development. The second, cross-sectional study contributed a new methodology to studying the relationship between sleep (quality) and neurocognitive development. A customised NIRS-EEG system was used as a novel way to study infant brain activity during sleep. This project enables further research into sleep in a developmental context including the potential use of a wireless NIRS-EEG system to study sleep in naturalistic settings and of sleep fragmentation as a target for sleep-based interventions for children with neurodevelopmental disorders

Furtherfield: twenty years of art, technology, and social change

Furtherfield is London’s longest-running centre for art and technology. Its current mission is to disrupt and democratise art and tech through co-creation, in-depth exploration, open tools and free-thinking. Since 1996 Furtherfield has developed an international reputation for initiating experiments in artistic co-creation across digital networks. As a global hub that has grown up on the web, the time and energy of its team and participants have been focused on decentralised and distributed peer-to-peer practices, fostering new projects with artists, and seizing and challenging debates about the role of art and technology in society. Founded by Ruth Catlow and me, it is an international hub and community for artists, technologists, writers and cultural hackers. Furtherfield has two venues, the commons and the gallery, in the heart of London’s 150-year-old, Finsbury Park. This research presents an autoethnographic study of Furtherfield’s twenty-three-year history to date. The study focuses on the motives, strategies, and values of the Furtherfield community as expressed through its projects and debates which are often critical of UK art-market frameworks and belief systems. It examines the relationship between essential artistic practices and social, political, and cultural conditions associated with the emergence of planetary-scale network technologies. It presents and analyses the significant role played by artists in reshaping the narratives and uses of these technologies. Since its inception, Furtherfield has formed alliances with artists, technologists and activists, dedicating their lives to learning and updating their skills and practices, questioning the values, defaults, and structures of art-world systems that support and promote established norms in cultural production. This thesis draws on public documents, interviews, and private records for its autoethnographic research. In doing so, this thesis aims to present an objective analysis of the materials, while acknowledging the inevitable partiality of any study of community practice in the networked environment. Through an examination of people, platforms, places, campaigns, theoretical groundings, and public programmes this research traces key social themes of a dynamic organisation shaped by a plurality of voices from the margins and with the community at its heart

Neuroimaging investigations of the functional and structural changes of intrinsically connected brain networks in relation to habitual sleep status

This thesis uses fMRI and DTI neuroimaging modalities to investigate relationships between chronic habitual sleep status in waking control subjects and functional and structural changes in higher order intrinsically connected brain networks (ICN). Study one investigates methodologies; compares the use of deterministic and probabilistic tractography in combination with functional imaging to charaterise structural connectivity with respect to functional connectivity in a single ICN. The following chapter examines whether inter-individual differences in habitual sleep patterns are reflected in waking measurements of network functional connectivity (FC) between three ICNs. Subsequent work investigates group differences in structural connectivity with respect to habitual sleep duration and whole brain changes in white matter in relation to subjective habitual sleep quality using tract based spatial statistics (TBSS). The final chapter builds on the work from previous chapters examining a wider range of sleep features and overall network FC. Results presented in this thesis provide evidence of functional and structural brain connectivity changes, which are modulated by chronic habitual sleep status. This may help to elucidate the link between sleep, waking sleep status, cognition and explain individual differences in susceptibility to sleep deprivation, as well as potentially the networks and systems responsible for variations in sleep patterns themselves

The Impact of Short-Term Sleep Extension on Cognitive and Motor Performance in College Tactical Athletes

U.S. service members are commonly referred to as “tactical athletes” because of the physical training they undergo to maintain and improve occupational performance. Because performance in the military can literally determine the outcome in ‘life and death’ situations, it is critical that tactical athletes are prepared to perform optimally, both physically and mentally. Accordingly, it is important for tactical athletes to focus on health behaviors, like sleep, known to impact both aspects of performance. Little is known about the sleep health of college tactical athletes enrolled in The Reserve Officer's Training Corps (ROTC) and there have been no well-controlled studies on the immediate and residual effects of sleep extension on executive and cognitive motor performance. To address this knowledge gap, a randomized control trial (Sleep extension versus Control) was conducted to determine the immediate and residual effects of a four-night sleep extension intervention (10 hours time in bed) in this population. Consented participants wore a wrist actigraph for fifteen nights in order to measure sleep duration and a cognitive motor battery was conducted after seven nights of habitual sleep (Day 8 – pre-test), after the four nights of sleep extension intervention (Day 12 – post-test), and after the resumption of habitual sleep for four nights (Day 16 – follow-up). Between group comparisons of mean pre- to post-test score changes and mean pre-test to follow-up score changes were performed using independent sample t-tests. Results revealed that the sleep extension group significantly increased their mean sleep duration over the intervention period and that the four nights of sleep extension resulted in immediate benefits in alertness, psychomotor vigilance/attention, executive function performance, standing broad jump performance, and motivation levels. Benefits of sleep extension on broad jump performance and motivation level were still evident four days after resumption of habitual sleep schedules. These results suggest that sleep extension enhances both cognitive and motor performance in college tactical athletes, with some performance benefits lasting days after returning to habitual sleep patterns. Considering the performance improvements noted following sleep extension, a four-night intervention should be considered for training programs aiming to enhance overall performance

The new science of sleep: From cells to large-scale societies

In the past 20 years, more remarkable revelations about sleep and its varied functions have arguably been made than in the previous 200. Building on this swell of recent findings, this essay provides a broad sampling of selected research highlights across genetic, molecular, cellular, and physiological systems within the body, networks within the brain, and large-scale social dynamics. Based on this raft of exciting new discoveries, we have come to realize that sleep, in this moment of its evolution, is very much polyfunctional (rather than monofunctional), yet polyfunctional for reasons we had never previously considered. Moreover, these new polyfunctional insights powerfully reaffirm sleep as a critical biological, and thus health-sustaining, requisite. Indeed, perhaps the only thing more impressive than the unanticipated nature of these newly emerging sleep functions is their striking divergence, from operations of molecular mechanisms inside cells to entire group societal dynamics

Does sleep affect socio-emotional functioning?

In the first chapter I compare and contrast the extant literature on sleep loss and insomnia, including theories as to how insomnia develops and the role of the circadian and homeostatic systems. In Chapter 2 I summarize the extant literature on sleep, emotion perception, and social task performance, and review the relevant emotion literature. I then critically appraise this literature and suggest future directions for this field. In Chapter 3 I pilot an emotion recognition task among students, including measures of sleep and empathy. Results suggest that the previous nights’ sleep, as well as depression scores, are significant predictors of happiness recognition. In Chapter 4 I assess emotion recognition in insomnia using dynamic stimuli, and results suggest that insomnia disorder impairs the categorization accuracy of high intensity expressions of sadness and low intensity expressions of surprise. Sleep diary parameters were also found to be significant predictors of happiness recognition on both accuracy and reaction time measures. I then assess how normal sleepers perform with these stimuli in Chapter 5, testing subjects at different times since waking. Chapter 5 Experiment One suggests that the early group are more sensitive towards several temporal parameters, with no effects on emotion recognition. Chapter 5 Experiment Two suggests that normal sleepers tested early are less sensitive towards mid-intensity expressions of anger and sadness, with effects on intensity recognition. These results are interpreted in the context of differences with the two late-tested groups. Chapter 6 extends these results to static stimuli, with results suggesting that the early group tend to make more errors when categorizing happy faces. Chapter 7 returns to the daytime impairments in insomnia disorder, suggesting that theory of mind task performance is altered when reaction times are measured. As a result of issues raised in this thesis Chapter 8 systematically reviews the literature on how normal sleepers are screened for participation in research studies, suggesting future criteria. Chapter 9 summarizes these results in the context of hyperarousal and the etiology of insomnia disorder

The effect of cognitive training on subsequent sleep characteristics

Introduction: Several studies have consistently shown that pre-sleep learning produces changes in sleep structure. Whereas the majority of these studies has mainly focused on post-training changes in sleep states (namely REM and NREM sleep amount) and, more recently, in specific electrophysiological features (e.g., sleep spindles, slow wave activity), very little attention has been paid to the hypothesis that pre-sleep learning might improve sleep quality, as expressed by sleep continuity, stability and cyclic organization measures. Furthermore, studies addressing the relationship between sleep and learning usually employ purely declarative or procedural tasks, neglecting that everyday life learning processes depend on the simultaneous activation of different memory systems. Recently, we have reported that a complex ecological learning task (requiring the simultaneous activation of several cognitive functions), intensively administered at bedtime, improves daytime sleep continuity and stability, possibly as a result of ongoing memory processes. To follow up our previous study, here we aimed to extend these findings to a night paradigm and to test whether a similar post-training sleep improvement may be obtained in a sample of individuals with sleep complaints. Specifically, our focus was on post-training changes in objective and subjective sleep quality. Furthermore, we compared overnight performance changes with those obtained over a wake retention period, in order to address the possible differential effect of sleep and wake on memory processes. Method: After a habituation night, twenty-one subjects (F=15, mean age: 27.5±7.7 years, all bad sleepers according to the Pittsburgh Sleep Quality Index) underwent conventional polygraphic recording under three conditions: 1) BL, baseline night sleep; 2) post-active control sleep (AC), a sleep episode preceded by a non-learning control task; 3) post-training sleep (TR), a sleep episode preceded by a complex ecological task. The same task as in TR was administered in a Wake condition (W), in which the retention period between training sessions corresponded to the duration of the subject’s baseline sleep time. Subjects underwent AC, TR and W conditions in balanced order. The complex cognitive task consisted in a slightly modified version of the famous word game “Ruzzle”. In this game, the player has two minutes to form as many words as possible and reach the highest score achievable with the 16 letters available in a 4x4 grid on an iPad screen. Performance measures were R-WORDS%, i.e., the number of detected words over total available words, and R-SCORE%, i.e., the global score achieved, depending on the number of words found, on their length and on the ability to use the coloured bonus letters which multiply letter or word values. Results: Post-training sleep (TR) showed a reduction in Stage 1 proportion (F=4.39, p=.021; TRTR and AC) and brief awakenings frequency (F=5.89, p=.007, BL>TR and AC), decreased frequency of arousals (F=6.25, p=.005; TRTR and AC) and functional uncertainty (FU) periods (F=14.23, pTR and AC), as well as a reduction of time spent in FU periods (F=515.33, pTR and AC); an increase in the number of NREM-REM cycles (F=4.51, p=.019; TR>BL and AC), and of time spent in cycles (F=4.77, p=.015; TR>BL and AC). This improvement in objective sleep quality was paralleled by that in subjective ratings, assessed through the Self-Rating Scale for Sleep and Awakenings Quality (χ2=9.13, p=.010; TRW), while the opposite effect emerged for the R-WORDS% (t=-2.96, p=.01; W>TR). Conclusions: Our results extend previous findings on post-training changes in sleep continuity, stability and organization to a sample of bad sleepers; also, they show that objective sleep improvement may be reflected in subjective sleep quality perception. Interestingly, the active control task also produced improvements in some of these features, prompting future investigations on the contribution to post-training sleep changes of additional factors not specifically linked to learning processes. As for performance, the finding of a significant sleep effect for the more complex performance measure (R-SCORE%) suggests that sleep preferentially promotes effective learning of elaborate cognitive strategies rather than that of simpler cognitive processes. In conclusion, in light of the importance of non-pharmacological treatments for sleep disturbances, this study offers the possibility to further explore planned cognitive training as a low-cost treatment strategy to improve sleep quality

Consequences of Chronic Sleep Restriction on Energy Balance in Healthy Adults

Habitual short sleep duration is consistently associated with weight gain and increased risk for obesity. The objective of this dissertation was to elucidate how chronic sleep restriction impacts components of energy balance, namely, weight gain, energy intake, and energy expenditure. Healthy adults (21-50 y) participated in controlled isolated laboratory protocols for 14-18 days and were randomized to either an experimental condition (baseline sleep followed by sleep restriction [5 consecutive nights of 4 hours time-in-bed [TIB] per night] and recovery sleep) or control condition (no sleep restriction: 10 hours TIB per night for all nights). Sleep-restricted subjects exhibited significant weight gain, increased caloric intake, greater consumption of fat, delayed meal timing and decreased resting metabolic rate (the largest component of energy expenditure) during sleep restriction but these changes returned to baseline levels after one night of recovery sleep (12 hours TIB). Control subjects did not exhibit a significant change in weight, caloric intake or resting metabolic rate across corresponding protocol days. Notably, there were significant gender and race differences in the energy balance response to sleep restriction. Men gained more weight, increased caloric intake to a greater degree during sleep restriction and consumed a larger percentage of calories during late-night hours than women. Relative to Caucasians, African Americans consumed a comparable amount of calories during baseline and sleep restriction but exhibited marked energy expenditure deficits after baseline sleep, sleep restriction and recovery sleep, and gained more weight during the study. In the largest, most diverse healthy sample of adults studied to date under controlled laboratory conditions, sleep restriction promoted weight gain and positive energy balance. Collectively, these results highlight the importance of obtaining sufficient sleep for regulating energy balance and maintaining a healthy weight, particularly in men and African Americans

Attention in the Brain Under Conditions of Sub-Optimal Alertness: Neurobiological Effects and Individual Differences

Sleep deprivation (SD) is a prevalent problem in modern society, and one that can have serious adverse consequences for health and safety. Critically, even short periods of SD can lead to relatively large decrements in attention, which may in turn cause an individual to neglect important environmental stimuli. In this thesis, I report the results of three experiments designed to investigate the neural bases of attentional declines under conditions of sleep loss and mental fatigue. In two experiments using arterial spin labeled fMRI, a technique that enables the quantification of absolute levels of cerebral blood flow (CBF), it was found that CBF patterns in the resting brain differed significantly based on arousal levels (Study #1) and prior cognitive workload (Study #2). These findings are a departure from prior neuroimaging studies, which have typically taken neural activity during non-task periods as static and inseparable baseline. In a test of sustained attention, performance declines were observed both following SD (Study #1) and when performing the task for an extended period of time while well-rested (Study #2). These decrements were primarily mediated by hypoactivation in a fronto-parietal attentional circuit. Furthermore, resting baseline levels of cerebral blood flow in the thalamus and prefrontal cortex before the start of the task were predictive of interindividual differences in subsequent performance decline (Study #2). In Study #3, an experiment using standard BOLD fMRI, it was found that performance declines in a test of selective attention following SD were accompanied by reduced functional connectivity between top-down control areas and regions of ventral visual cortex, as well as reductions in activation to targets in object-selective areas. Taken together, these results further our understanding of the neural basis of attention under conditions when this system is taxed beyond its normal limits