The Social and Sleep Share a Two-Way Sheet: Investigating the Reciprocal Dynamics Between Sleep, Social Behaviour, and Oxytocin

Abstract

Although sleep, social behaviour, and the neuropeptide oxytocin attract substantial research interest as independent fields, little attention has been directed toward the interface between these fields of study—the sleep-social-oxytocin nexus. This thesis aims to (i) synthesise and generate experimental and theoretical evidence for the sleep-social-oxytocin nexus, (ii) challenge classical conceptualisation of each field’s independence, (iii) and establish a foundation for future research within this interactive research space. Chapter 1 consists of a preliminary review of sleep, social processes, and oxytocin, followed by a comprehensive synthesis of experimental and theoretical evidence supporting established and potential interactions existing within the nexus, and concludes with an outline of the thesis aims, research questions, and research program. Chapter 2 systematically reviewed the extant clinical and preclinical literature assessing the influence of oxytocin-based interventions on sleep-wake and sleep-related outcomes. Chapter 3 investigated whether dose, route of administration, and biological sex modulate oxytocin’s influence on sleep-wake behaviour and neurophysiology. Chapter 4 piloted the social operant conditioning model and explored which experimental parameters might modulate social motivation, and Chapter 5 systematically explored the effects of biological sex, housing conditions, time-of-day of testing, and stimulus sex on social motivation within the model using behavioural economics and video analysis. Chapter 6 explored whether the social consequences of sleep loss depend on the method and timing of sleep deprivation, evaluated whether sleep loss produced social-specific or general reductions in motivation, and examined whether acute caffeine administration could prevent sleep loss-induced asociality. Lastly, Chapter 7 summarises and contextualises the thesis findings within the dynamic reciprocal framework of the sleep-social-oxytocin nexus.