Altered Brain Functional Connectivity at Resting-State in Patients With Non-arteritic Anterior Ischemic Optic Neuropathy

Abstract

Purpose: To investigate the possible changes in functional connectivity (FC) in patients with non-arteritic anterior ischemic optic neuropathy (NAION) using resting-state functional MRI (fMRI). Methods: Thirty-one NAION patients and 31 healthy controls were recruited and underwent resting-state fMRI scans. Regions of interest (ROIs) were defined as bilateral Brodmann's area 17 (BA17). FC analysis was performed between the ROIs and the rest of the brain regions, and the between group comparisons of FC were performed. We conducted correlation analysis between the FC changes and the clinical variables in NAION patients. Results: Compared with healthy controls, patients with NAION showed significantly decreased FC between the left BA17 and the right inferior frontal gyrus, left caudate nucleus. As for the right BA17, patients exhibited significantly increased FC with the left olfactory gyrus and decreased FC with the right superior frontal gyrus (SFG), right insula. Moreover, FC values between the right insula and the right BA17 were positively correlated with the right side of mean sensitivity in the central visual field (r = 0.52, P < 0.01) and negatively correlated with the right side of mean defect in the central visual field (r = -0.55, P < 0.01). Conclusion: Our study indicated that patients with NAION showed significantly abnormal functional reorganization between the primary visual cortex and several other brain regions not directly related to visual function, which supports that NAION may not only be an ophthalmic disease but also a neuro-ophthalmological disease.

Keywords: functional connectivity; functional magnetic resonance imaging; neural plasticity; non-arteritic anterior ischemic optic neuropathy; resting state.

FIGURE 1

The brain regions with significant FC changes in NAION patients when the left BA17 was used as the seed region. FC, functional connectivity; NAION, non-arteritic anterior ischemic optic neuropathy; BA, Brodmann’s area.

FIGURE 2

The brain regions with significant FC changes in NAION patients when the right BA17 was used as the seed region. FC, functional connectivity; NAION, non-arteritic anterior ischemic optic neuropathy; BA, Brodmann’s area.

FIGURE 3

Correlation analysis between the FC values in brain regions with significant differences and clinical variables. (A) The Pearson correlation shows a positive association between the mean FC values in the right insula and the right side of MS in NAION patients. (B) The Pearson correlation reveals a negative association between the mean FC values in the right insula and the right MD in NAION patients. FC, functional connectivity; NAION, non-arteritic anterior ischemic optic neuropathy; MS, mean sensitivity; MD, mean defect.

FIGURE 4

The mean FC values in the brain areas with significant differences between NAION patients and HCs as diagnostic indicators. (A) ROC curve analysis of the mean FC values in the right IFG and left caudate nucleus, respectively, for differentiating NAION patients from HCs when the left BA17 was used as the seed region. (B) ROC curve analysis of the mean FC values in the right SFG and left olfactory gyrus, respectively, for differentiating NAION patients from HCs when the right BA17 was used as the seed region. (C) ROC curve analysis of the combination of the four brain areas (including the right IFG, right SFG, left olfactory gyrus, and left caudate nucleus) for differentiating NAION patients from HCs. FC, functional connectivity; NAION, non-arteritic anterior ischemic optic neuropathy; HCs, healthy controls; BA, Brodmann’s area; IFG, inferior frontal gyrus; SFG, superior frontal gyrus; ROC, receiver operating characteristic.