A Multi-Method Investigation of Circadian Rhythms, Sleep, And
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Running Head: BIOLOGICAL RHYTHMS & REWARD MOTIVATION A Multi-Method Investigation of Circadian Rhythms, Sleep, and Affective States: Characterising Modulation, Imaging Reward Mechanisms, and Improving Clinical Measurement Jamie E. M. Byrne Centre for Mental Health, Faculty of Health, Arts, and Design, Swinburne University of Technology Submitted in the year of 2018 A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Clinical Psychology) qualification at Swinburne University of Technology BIOLOGICAL RHYTHMS & REWARD MOTIVATION ii Abstract The relationship between biological rhythms (circadian and sleep-wake processes) and reward motivation is proposed to be important, with circadian modulation of reward motivation one pathway in this relationship. To date, the relationship between biological rhythms and reward motivation has largely been investigated in animal studies, with limited exploration of this important interaction in humans. The aim of this project was to incrementally advance understanding of the relationship between biological rhythms and reward motivation in humans. To do this, the relationship between biological rhythms and reward motivation was reviewed (Study 1) and psychometrically examined (Study 2). Study 2 psychometrically quantified the separation of sleep quality, diurnal preference, and mood leading to the generation and initial psychometric testing of a new self-report measure of sleep quality, circadian functioning and depressed mood. The remaining three studies focused on the circadian component of biological rhythms, investigating critical aspects of a putative circadian modulation of reward motivation. Study 3 examined diurnal variation in three psychological components of reward. Findings indicated that unconscious “wanting” and conscious wanting of rewards exhibited diurnal variation peaking at 14:00h with diurnal variation in conscious liking and learning not fitting a waveform peaking at 14:00h. Study 4 systematically reviewed circadian modulation of neural reward functioning in functional magnetic resonance imaging (fMRI) studies. Of the 15 included studies, 13 studies generated some evidence of circadian modulation of reward functioning with altered ventral striatum, medial prefrontal cortex, and default mode network activation most consistently associated with circadian parameters. In Study 5, diurnal variation in reward motivation was examined in a block-design fMRI study in response to a well-validated reward task. The left putamen displayed significantly less activation at 14:00h relative to 10:00h and 19:00h which may reflect a circadian-driven prediction error of the brain. The current findings advance evidence of a relationship between biological rhythms and reward motivation in humans at multiple biobehavioural levels. In particular, this project has found evidence for diurnal variation of reward motivation, a preliminary step in investigating modulation of reward motivation by circadian functioning. Further work is now needed to consider the clinical translation of the relationship between biological rhythms and reward motivation. Additionally, future research BIOLOGICAL RHYTHMS & REWARD MOTIVATION iii should systematically investigate the relationships between the multifaceted construct of reward motivation and the range of processes involved in biological rhythms. BIOLOGICAL RHYTHMS & REWARD MOTIVATION iv Acknowledgements I am in the fortunate position to have thoroughly enjoyed my PhD candidature. While it is in part due to my love of the research area, it is largely the people I am surrounded by who have made this an enjoyable experience. Firstly, I am immensely grateful to my supervisors Professor Greg Murray, and Dr. Ben Bullock. Aside from the dramatic growth to my knowledge, research, and writing skills, Professor Murray has created a nurturing and supportive learning environment, and I have flourished under his supervision. I have learned, and continue to learn, so much from his mentorship. Dr. Bullock’s feedback and ongoing support has been invaluable. He has been instrumental in helping me to hone my skills in attention to detail and being patient in my approach to learning. I would like to thank Dr. Matt Hughes for his work on the fMRI analyses and teaching me fMRI study designs and analyses. I am grateful to Professor Susan Rossell for her position as chair of my progress committee, her ongoing guidance, and running late night sessions in the MRI for my project. Finally, I feel supported and loved by so many friends and family who have not only been there for the length of my PhD but for my life. In the interests of space, I’ll name but a few: Chris, Stefan, and my sister Amy, thanks for putting up with me. Loki, you live up to your name, but for two years and counting you have kept me mindful and happy. To my parents Dr. Gail and Anthony Byrne, I do not know where to begin thanking you. Mum you went through the PhD journey a second time with me, and I am grateful for the unconditional love you and Dad have always shown me. BIOLOGICAL RHYTHMS & REWARD MOTIVATION v Declaration In submitting this thesis in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Clinical Psychology) by Associated Papers at Swinburne University of Technology, I declare that the following work: 1. Contains no material which has been accepted for the award to the candidate of any other degree or diploma, except where due reference is made in the text of the examinable outcome; 2. To the best of the candidate’s knowledge contains no material previously published or written by another person except where due reference is made in the text of the examinable outcome; and 3. Where the work is based on joint research or publications, discloses the relative contributions of the respective workers or authors. Signed Jamie E. M. Byrne BIOLOGICAL RHYTHMS & REWARD MOTIVATION vi Table of Contents List of Tables............................................................................................................. xiv List of Figures ............................................................................................................ xv List of Appendices ................................................................................................... xvii List of Publications Arising from the Project ......................................................... xviii Chapter 1: Overview of the Project .............................................................................. 1 1.1 Variables Under Investigation in the Present Project ................................ 3 1.2 Overview of the Thesis Document ......................................................... 11 Chapter 2: The Circadian System .............................................................................. 13 2.1 The Circadian System ............................................................................. 14 2.1.1 The molecular genetics of the circadian system. .............................. 14 2.1.2 Zeitgebers. ......................................................................................... 15 2.1.3 Parameters of the circadian system. .................................................. 16 Figure 2. Circadian parameters in both entrained (light-dark) and free- running (constant darkness) conditions ............................................... 17 2.1.3.1 Period. .................................................................................... 17 2.1.3.2 Phase. ..................................................................................... 17 2.1.3.2.1 Measuring phase. ................................................... 18 2.1.3.2.2 Relationship between circadian phase and chronotypes. ............................................................................ 18 2.1.3.3 Amplitude. ............................................................................. 21 2.2 Diurnal Rhythms .................................................................................... 22 2.3 Measuring Circadian Rhythms ............................................................... 22 2.3.1 Constant routine protocol. ................................................................. 23 2.3.2 Forced desynchrony protocol. ........................................................... 23 2.4 Features of the Circadian System Interact .............................................. 23 2.4.1 The phase response curve in humans. ............................................... 24 2.5 Borbély’s Two-Process Model of Sleep Regulation. ............................. 24 2.6 Implications of Circadian Masking Factors for Research into Biological Rhythms in Humans ........................................................................................... 27 2.7 Summary .................................................................................................. 27 Chapter 3: Reward Motivation ................................................................................... 29 3.1 An Evolutionary Explanation of the Reward System ............................. 30 3.2 Reward Neurocircuitry ........................................................................... 30 3.3 The Three Psychological Components of Reward ................................. 34 3.3.1 Evidence for dissociating reward components in animals. ............... 35 BIOLOGICAL RHYTHMS & REWARD MOTIVATION vii 3.3.2 Evidence for dissociating reward components in humans. ............... 37 3.4 Reinforcement