The sleep and circadian modulation of neural reward pathways: a protocol for a pair of systematic reviews

Abstract

BackgroundAnimal research suggests that neural reward activation may be systematically modulated by sleep and circadian function. Whether humans also exhibit sleep and circadian modulation of neural reward pathways is unclear. This area is in need of further research, as it has implications for the involvement of sleep and circadian function in reward-related disorders. The aim of this paper is to describe the protocol for a pair of systematic literature reviews to synthesise existing literature related to (1) sleep and (2) circadian modulation of neural reward pathways in healthy human populations.MethodsA systematic review of relevant online databases (Scopus, PubMed, Web of Science, ProQuest, PsycINFO and EBSCOhost) will be conducted. Reference lists, relevant reviews and supplementary data will be searched for additional articles. Articles will be included if (a) they contain a sleep- or circadian-related predictor variable with a neural reward outcome variable, (b) use a functional magnetic resonance imaging protocol and (c) use human samples. Articles will be excluded if study participants had disorders known to affect the reward system. The articles will be screened by two independent authors. Two authors will complete the data extraction form, with two authors independently completing the quality assessment tool for the selected articles, with a consensus reached with a third author if needed. Narrative synthesis methods will be used to analyse the data.DiscussionThe findings from this pair of systematic literature reviews will assist in the identification of the pathways involved in the sleep and circadian function modulation of neural reward in healthy individuals, with implications for disorders characterised by dysregulation in sleep, circadian rhythms and reward function.Systematic review registrationPROSPERO CRD42017064994Electronic supplementary materialThe online version of this article (10.1186/s13643-017-0631-3) contains supplementary material, which is available to authorized users.

Identifying Diurnal Variability of Brain Connectivity Patterns Using Graph Theory

“…Although effects of circadian rhythms and chronotypes on whole-brain connectivity have been examined (some cases have only considered time of day [ 17 ]), the results are often contradictory and inconsistent. For example, a group of researchers believe that resting-state brain networks maintain a constant topological organization throughout the day [ 18 , 19 ], while others believe that brain networks, especially default mode, sensorimotor, and visual networks, show significant changes as the day progresses when we are at rest [ 20 , 21 , 22 ]. Additionally, Orban et al [ 23 ], contrary to the common belief that “global brain signal is low in the morning and then increases in the midafternoon, and drops in the early evening”, showed that the global signal fluctuation is continuously decreasing during the day.…”

Beyond the Low Frequency Fluctuations: Morning and Evening Differences in Human Brain

“…All above-mentioned studies concerned particular neuropsychological functions examined by performing specific tasks. Resting-state networks are mostly believed to remain stable throughout the day (Biswal et al, 2010; Byrne and Murray, 2017). An opposite view was postulated by Blautzik et al (2013) and Park et al (2012), who argued that the level of stability varies over a period of 1 day across different resting state networks, ranging from highly rhythmic to stable.…”

Assessment and treatment of sleep problems in bipolar disorder—A guide for psychologists and clinically focused review

“…Furthermore, sleep problems are not specific to BD and are ubiquitous across psychiatric conditions (Baglioni et al, ; Remi, Pollmacher, Spiegelhalder, Trenkwalder, & Young, ); there may also be transdiagnostic mechanisms that influence the relationship between sleep and mental ill‐health (Harvey, Murray, Chandler, & Soehner, ). In the opinion of the present authors, valid characterization of the relationship between sleep and mood relapses in BD will ultimately account for interplay between multilevel psychophysiological systems involved in mood (positive affect/reward, negative affect/threat), biological rhythms (the circadian system and its output rhythms), and sleep homeostasis (see for discussion: Alloy, Nusslock, & Boland, ; Byrne & Murray, ; Byrne et al, ). Importantly, volitional behaviour in the environment is a facet of each of these three adapted processes, underscoring the potential importance of behavioural causes, behavioural maintaining factors, and behavioural treatments (below).…”