The Effect of Physiological Modulators on Resting-state fMRI Functional Connectivity

In this thesis, we focus on the following physiological modulators of the blood oxygenation level dependent (BOLD) signal â cerebral blood flow (CBF), venous-blood oxygenation, and cerebrovascular reactivity (CVR). We use simulations and experiments to examine the relationship between the physiological parameters with rs-fMRI functional connectivity measurements in three resting-state networks: default-mode network (DMN), sensori-motor network (SMN), and the visual network (VN). By using the general linear model, we demonstrate that physiological modulators significant impact functional connectivity measurements in these regions, both within subjects and between subjects. Moreover, we found that the physiological effects vary depending upon brain region and individual. The results confirm that it is important to account for the effect of physiological noise when examining resting-state fMRI functional connectivity, in the study of healthy brain function, but more importantly, in states of altered brain function.M.Sc