Functional brain connectivity and cerebral blood flow in glaucoma across disease severity

Glaucoma is a neurodegenerative disease of the visual system, and it is a worldwide leading cause of irreversible vision loss. It is characterized by progressive degeneration of the optic nerve head and retinal ganglion cells but mounting evidence shows that the entire visual pathway could be damaged, and some non-visual parts of the brain might also be affected. Whether the brain is involved in glaucoma at an early stage, how the brain interacts with the eye across disease severity are all still up for debate. In this thesis work resting state functional (rsfMRI) and pseudo-continuous arterial spin labeling (pCASL) magnetic resonance images of healthy and glaucoma subjects detected at the Center of Biomedical Imaging, NYU Langone Health, Radiology Department, have been analyzed. The objective of this research was to explore functional brain connectivity (FC) and cerebral blood flow (CBF) alterations across the disease severity stages in some regions of interest (ROIs) known to be involved in the regulation of behaviors affected in glaucoma, such as anxiety, attention, and sleep-wake modulation. The analyzed ROIs are the ventrolateral preoptic nucleus (VLPO), locus coeruleus (LC), habenula, median (MR) and dorsal raphe (DR), ventral tegmental area (VTA), posterior hypothalamus (PH) and basal forebrain (BF). The study also aimed to analyze the correlation between these changes in the brain and changes in the inner structure of the retina. rsfMRI and pCASL images have been processed using respectively the CONN and ASAP toolboxes. Statistical methods have been applied to detect significant alterations in FC and CBF in early and advanced glaucoma stages in the ROIs. Through this analysis, FC alterations have been found in the ROIs, except in MR and DR, while CBF alterations have been found in MR and LC. The results also suggest that inner retina structure degeneration could be correlated with FC changes but not with CBF alteration.