Dynamics of the cortical responsiveness during extended wakefulness, in young and older participants.

Although it has been established that human brain physiology and cognition are under the joint effect of the sleep homeostasis and the circadian alerting signal, the detrimental effect of sleep deprivation is still mostly seen as merely a consequence of a lack of sleep. While this approach is valuable, in order to develop a complete understanding, a circadian perspective needs to be integrated. However, a major difficulty of measuring circadian rhythmicity stems from the complexity of assessing it, because confounders such as light, activity, meals etc. could mask the underlying circadian regulation. Here, we performed two constant routine studies that allow us to measure the interaction between sleep homeostasis and the circadian processes at the cortical level. During the studies, three complementary aspects of the cortical function were investigated, as well as their associations with behavioural performance, and age-related changes of the cortical dynamics. In phase I of the study, the dynamics of cortical excitability, and of response scattering and complexity were described during a 28 hour wake extension protocol in young participants (18-30 y). In phase II, the dynamics of cortical excitability and response complexity were investigated during a 34 hour wake extension in young (18-30 y) and older (50-70 y) participants in order to address lifetime changes. Overall, the results of this thesis demonstrated an age-dependent homeostatic and circadian regulation of basic cortical function. That was especially evident at the local level, when focusing on cortical excitability profile: young participants showed a clear circadian rhythmicity and sleep homeostasis regulation, the dynamic of which was dampened in the older participants. At the global level, cortical response scattering and complexity changed with time spent awake, i.e. according to the circadian phase Furthermore, cortical complexity response was higher in the older group, showing a simple age effect, but the dynamic did not differ between the two age groups. Preliminary analyses demonstrated that these cortical dynamics sustain part of the profile of behavioural performance across the circadian cycle. Importantly, older people with higher cortical excitability, particularly during the biological night, were performing better at higher order tasks, possibly indicating that older people that maintain a degree of sensitivity toward sleep homeostasis and circadian processes perform better. Understanding the principal forces that regulate the dynamics of cortical neurophysiology in two age groups –and their impact on cognition– is of uppermost importance for our ageing society, in which sleep deprivation and circadian misalignment are commonplace

Steady-State Pupil Size Varies with Circadian Phase and Sleep Homeostasis in Healthy Young Men

peer reviewe

Time course of cortical response complexity during extended wakefulness and its differential association with vigilance in young and older individuals

peer reviewe

Investigating the longitudinal bi-directional relationship between self-reported restrictive eating behaviours and sleep in UK adolescents within the Millennium Cohort Study

Objective: This study aimed to investigate the longitudinal bi-directional relationship between self-reported restrictive eating behaviours and sleep characteristics within a sample of UK adolescents from the Millennium Cohort Study (MCS). Method: Using a Structural Equation Modelling approach, the present study investigated the prospective associations between individual sleep behaviours (e.g., sleep timing, sleep onset latency, social jetlag) at age 14 and restrictive eating behaviours at age 17. Moreover, the association between restrictive eating behaviours (age 14) and self-reported sleep quality (age 17) was tested. A mediation analysis was conducted to explore the role of depressive symptoms in these relationships. In total, N = 6,041 young people provided self-report data at both timepoints (sweep 6 &amp; 7) and a subsample of N = 2,164 additionally provided diary data on their sleep behaviours over two separate 24 h periods. Results: Sleep indicators at age 14 did not significantly predict changes in restrictive eating behaviours across time. However, engagement in restrictive eating behaviours at age 14 significantly predicted poorer self-perceived sleep quality three years later (β = 0.06, SE = 0.01, p &lt;.01). Depressive symptoms fully mediated this relationship (indirect effect: β = 0.05, SE = 0.04, p &lt;.001). Discussion: The present study provides evidence for a prospective positive association between restrictive eating behaviours and subsequent poorer sleep quality in a large, general population sample. Findings of the mediation analysis suggest mood as a potential target for tertiary prevention when addressing restrictive eating behaviours as an eating disorder risk factor in adolescents.</p

Time course of cortical response complexity during extended wakefulness and its differential association with vigilance in young and older individuals

peer reviewe

The association between disordered eating and sleep in non-clinical population:A systematic review and meta-analysis

Sleep and disordered eating behaviours may be linked through physiological and psychological mechanisms; yet, no review has systematically investigated the relationship between different sleep indicators and disordered eating behaviours and cognitions outside a clinical context. The present systematic review and meta-analysis addressed this research gap to gain a better understanding of associations in non-clinical populations to potentially inform future prevention and early intervention approaches in the context of both sleep and disordered eating. All studies published from 2003 onwards were included if they assessed a relationship between disordered eating and sleep in a non-clinical population. In total, 89 studies were included, of which 33 met eligibility criteria for the meta-analyses. General eating pathology, loss of control eating, and excessive exercise were most consistently significantly associated with poorer sleep quality and higher insomnia symptoms, while evening chronotypes were most consistently associated with bulimia symptoms, night eating, and body image concerns. Likely due to the limited evidence available, findings relating to restrictive eating behaviours and bulimia symptoms were largely mixed. Primarily small and non-significant effects were found for associations between disordered eating and sleep duration measures. Overall, this review identified a need for more longitudinal research, the use of validated assessment methods, and studies focusing on restrictive eating, bulimia-related behaviours, and excessive exercise. Despite the heterogeneity of study populations and designs, this review highlights sleep problems (e.g., insomnia symptoms, impaired sleep quality) as a transdiagnostic correlate of disordered eating concerns

A finite-element reciprocity solution for EEG forward modeling with realistic individual head models

peer reviewedHighlights • Creates EEG forward models suitable for high-resolution source localization. • Automatic T1-based whole-head finite element meshing and leadfield computation. • Pipelines can incorporate conductivity tensors from diffusion-weighted images. • Open-source toolbox shared under a permissive software license. • Accuracy comparable to SimBio FEM and superior to OpenMEEG BEM solutions

Ambient Teens Sleep Study:Protocol for a co-produced feasibility study in adolescents using a contactless radar-based sleep sensor

Sleep is crucial for the healthy development of adolescents, yet many suffer from chronic sleep deprivation. Over the transition to and course of adolescence there are known changes to sleep patterns e.g. shifts towards evening chronotypes. To study changes and patterns of sleep over these critical developmental time-points, detailed longitudinal data is required over months/years rather than weeks/days, a typical limitation of current technology. The implementation of novel contactless sleep sensors offers significant opportunities for longer term data collection, but their application has yet to be explored in young people in terms of feasibility, acceptability, performance and operability. The Ambient Teens Sleep Study will assess the feasibility of a contactless sleep sensor with approximately 45 adolescents aged 8–18 years, for 4 weeks. The device will be compared with accelerometery and sleep diary data, collected concurrently (2 weeks). Young people will provide feedback in the form of online calls and questionnaires as well as citizen scientist and product reviewer activities. Baseline questionnaires, conducted online, will be used to determine acceptability in different cohorts such as age, sex, gender and geographic location. We aim to assess completeness of data, participant experience and performance of sleep timing measures across all three methods of sleep assessment (contactless radar, accelerometery and sleep diary). The results will be used to inform longitudinal methods of sleep data collection in future adolescent health studies, at scale, to explore links between sleep and essential health outcomes across adolescent development

A pilot study of a ketogenic diet in bipolar disorder:clinical, metabolic and magnetic resonance spectroscopy findings

BACKGROUND: Preliminary evidence suggests that a ketogenic diet may be effective for bipolar disorder.AIMS: To assess the impact of a ketogenic diet in bipolar disorder on clinical, metabolic and magnetic resonance spectroscopy outcomes.METHOD: Euthymic individuals with bipolar disorder (N = 27) were recruited to a 6- to 8-week single-arm open pilot study of a modified ketogenic diet. Clinical, metabolic and MRS measures were assessed before and after the intervention.RESULTS: Of 27 recruited participants, 26 began and 20 completed the ketogenic diet. For participants completing the intervention, mean body weight fell by 4.2 kg (P &lt; 0.001), mean body mass index fell by 1.5 kg/m2 (P &lt; 0.001) and mean systolic blood pressure fell by 7.4 mmHg (P &lt; 0.041). The euthymic participants had average baseline and follow-up assessments consistent with them being in the euthymic range with no statistically significant changes in Affective Lability Scale-18, Beck Depression Inventory and Young Mania Rating Scale. In participants providing reliable daily ecological momentary assessment data (n = 14), there was a positive correlation between daily ketone levels and self-rated mood (r = 0.21, P &lt; 0.001) and energy (r = 0.19 P &lt; 0.001), and an inverse correlation between ketone levels and both impulsivity (r = -0.30, P &lt; 0.001) and anxiety (r = -0.19, P &lt; 0.001). From the MRS measurements, brain glutamate plus glutamine concentration decreased by 11.6% in the anterior cingulate cortex (P = 0.025) and fell by 13.6% in the posterior cingulate cortex (P = &lt;0.001).CONCLUSIONS: These findings suggest that a ketogenic diet may be clinically useful in bipolar disorder, for both mental health and metabolic outcomes. Replication and randomised controlled trials are now warranted.</p