Purpose: Network analysis was an effective way to assess brain function. The atlases used in network analysis were generated from healthy population, which may fail to reflect functional characteristic of the diseased brain. The aim of this study was to carry out functional connectivity (FC) analysis on primary open-angle glaucoma (POAG) patients using a data-driven parcellation atlas generated from the exactly same cohort.
Methods: Thirty-six POAG patients and 20 healthy controls underwent fMRI scans. K-means algorithm was used to generate a group-averaged parcellation atlas of visual cortices with 20 subregions using the FC profile from the 36 POAG patients. FC was then performed between POAG patients and healthy controls using this atlas among the 20 subregions in the visual cortices, and between the 20 subregions and the rest of the brain.
Results: A visual atlas with 20 subregions was generated. FC analysis via this atlas revealed that several functional connections in POAG patients were significantly decreased compared with healthy controls, while some functional connections were significantly increased compared with healthy controls. The decreased FCs in POAG patients were mainly between the visual cortices and the right hemisphere, and the increased FCs were mainly located between the visual cortices and left hemisphere. Significant correlations between decreased FCs and increased FCs were found in POAG group. In addition, we found clinical measures such as the elevated intraocular pressure had negative correlations with the decreased FCs.
Conclusion: POAG may lead to impaired visual networks and lateralization of functional changes in the brain. Functional compensation and inhibition loss mechanisms may occur in POAG brain. Furthermore, elevated intraocular pressure may decrease function connections between visual cortices and rest of the brain in POAG patients.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by the National Undergraduate Training Programs for Innovation and Entrepreneurship of China (S202010439016), Academic Promotion Program of Shandong First Medical University (2019QL009), and Taishan Scholars Program of Shandong Province (TS201712065).
Functional Imaging, MRI, Brain