Influence of Sevoflurane on Regional CBF & Functional Connectivity & Implications Related to Brain/Behavior During General Anesthesia

Maolin Qiu¹, Ramachandran Ramani², Roberto Martuzzi¹, Xiaohui Zhang¹, R. Todd Constable^1,3

Effects of sevoflurane on rCBF are observed across the brain cortices but are highly region-specific, with increases limited primarily to subcortical structures and insula and decreases observed primarily in neocortical regions. The functional connectivity within sub-neural networks appears to be much less affected by sevoflurane. With the assumption that both the resting state rCBF and functional connectivity are associated with the same underlying neuronal processes, we wanted to test whether a decrease in CBF during anesthesia would lead to a decrease in functional connectivity, and vice versa. Discrepancies between the changes in rCBF and connectivity caused by sevoflurane might suggest the differences in the neuronal processes with which they are associated. This work examined the relationship between local changes in rCBF and BOLD based functional connectivity in the awake and anesthetized state in humans. Regional CBF was significantly altered by sevoflurane across the brain while the network properties as measured using BOLD functional connectivity remained largely undisturbed. These discrepancies in the responses between rCBF and functional connectivity suggest that they are in general not associated with the same functional components of underlying neuronal processes.