Cerebrovascular reactivity mapping and its impact on BOLD fMRI of task induced activity and rest

Résumé

This thesis aims to investigate how cerebrovascular reactivity mapping (CVR), i.e. the physiological response of the cerebral vessels to vasodilatory or vasoconstrictive stimuli, impacts the BOLD fMRI measurements of task induced activity and resting state. After introducing the dataset collected to explore this topic, the first chapters will present a technique to optimise CVR mapping, considering its haemodynamic lag response and improve its denoising. Then, the impact that physiological processes such as blood pressure and pulse have on CVR will be assessed. Finally, the impact of CVR on task induced activity and resting state will be evaluated, in particular through the replication of two recent studies on the matter. The findings of this thesis support the idea that while physiological processes have a clear and direct impact on CVR, the impact of the latter on other BOLD measurements might be more complex, and requires further studies and investigations.