Placebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can shape our sensory... Show morePlacebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can shape our sensory experience. Although placebo and nocebo effects are known to occur reliably in many individuals for sensations like pain and itch, our understanding of psychological learning processes and methodological factors that influence these effects remains limited. Chapters 2, 3, and 4 investigate this topic with meta-analysis, narrative review, and a behavioral study. Similarly, our characterization of the neural markers of nocebo effects is incomplete. A better grasp of how these effects form is necessary to contextualize them within the larger framework of bottom-up and top-down integration. Chapters 5, 6, and 7 investigate this topic in a series of EEG and fMRI studies. Advancing both psychological and neural accounts of placebo and nocebo effects will aid in applying findings from this field of study to everyday life; particularly in clinical settings, and potentially any setting in which expectations regarding one’s future experiences come into play. Show less
The primary aim of this thesis was to improve the overall methodology for assessing supraclavicular brown adipose tissue (scBAT) activity in human adults to enable evaluation of therapies (in... Show moreThe primary aim of this thesis was to improve the overall methodology for assessing supraclavicular brown adipose tissue (scBAT) activity in human adults to enable evaluation of therapies (in)directly targeting BAT. The studies in this thesis have improved the feasibility of using non-invasive methods such as infrared thermography and magnetic resonance imaging for the assessment of scBAT activity in human adults and have led to a better understanding of the physiological mechanisms that influence the cold tolerance capacity in human adults. We showed the amount of activated BAT could vary among indi viduals with different body types and that cooling protocols should be carefully selected, especially in heterogenous study populations. With regards to imaging, we strongly recommend to use motion-correcting methods such as non-rigid image registration to correct for motion-induced variability, and to reduce the analysis time. Finally, due to the heterogenous nature of the scBAT depot in human adults, the use of FF thresholds for analysis should be carefully considered. Show less
Duchenne and Becker muscular dystrophy (DMD and BMD, respectively) are characterized by progressive loss of muscle function combined with an increase in fat tissue in muscle. In some muscles this... Show moreDuchenne and Becker muscular dystrophy (DMD and BMD, respectively) are characterized by progressive loss of muscle function combined with an increase in fat tissue in muscle. In some muscles this process of ‘fat replacement’ starts earlier or progresses faster than in others and this occurs in a consistent temporal pattern. In addition, even within muscles fat replacement seems to progress heterogeneously. Evidently there are factors that vary between and within muscles which cause differential fat replacement of muscle tissue, but these are currently unknown. The identification of factors that influence this process of muscle degeneration could support the selection of current, and the development of future, therapies.The aim of part 1 of this thesis was to identify differences between muscles that are related to muscle fat replacement over time. These can provide therapeutical targets for, and support the design of, future clinical trials in DMD and BMD. Part 2 aimed to develop new approaches to study intramuscular differences in muscle physiology and mechanics in healthy muscle. These can be applied in neuromuscular disease in the future, and can be related to intramuscular differences in disease progression. Show less
The general aim of this thesis was to study the frequency, causes and consequences of pathologic brain aging specifically focusing on sub-clinical and clinical MRI manifestations of vascular (small... Show moreThe general aim of this thesis was to study the frequency, causes and consequences of pathologic brain aging specifically focusing on sub-clinical and clinical MRI manifestations of vascular (small vessel disease) and neurodegenerative (brain atrophy) disease. A second aim was to improve the accuracy of the tools to quantify brain tissue so to better reflect the imaging characteristics of older people. All data presented in this thesis are from the AGES-Reykjavik Study including 5764 elderly men and women. The data is based on cross-sectional and longitudinal assessments of the brain with MRI measures. Show less
