Altered intrinsic regional spontaneous brain activity in patients with optic neuritis: a resting-state functional magnetic resonance imaging study

Abstract

Objective: To investigate the underlying regional homogeneity (ReHo) in brain-activity deficit in patients with optic neuritis (ON) and its relationship with behavioral performance.

Materials and methods: In total, twelve patients with ON (four males and eight females) and twelve (four males and eight females) age-, sex-, and education-matched healthy controls underwent resting-state functional magnetic resonance imaging scans. The ReHo method was used to assess the local features of spontaneous brain activity. Correlation analysis was used to explore the relationship between the observed mean ReHo values of the different brain areas and the visual evoked potential (VEP) in patients with ON.

Results: Compared with the healthy controls, patients with ON showed lower ReHo in the left cerebellum, posterior lobe, left middle temporal gyrus, right insula, right superior temporal gyrus, left middle frontal gyrus, bilateral anterior cingulate cortex, left superior frontal gyrus, right superior frontal gyrus, and right precentral gyrus, and higher ReHo in the cluster of the left fusiform gyrus and right inferior parietal lobule. Meanwhile, we found that the VEP amplitude of the right eye in patients with ON showed a positive correlation with the ReHo signal value of the left cerebellum posterior lobe (r=0.701, P=0.011), the right superior frontal gyrus (r=0.731, P=0.007), and the left fusiform gyrus (r=0.644, P=0.024). We also found that the VEP latency of the right eye in ON showed a positive correlation with the ReHo signal value of the right insula (r=0.595, P=0.041).

Conclusion: ON may involve dysfunction in the default-mode network, which may reflect the underlying pathologic mechanism.

Keywords: optic neuritis; regional homogeneity; rs-fMRI; visual evoked potential.

Figure 1

Significant differences in ReHo in the ON group, acquired by comparison to HCs. Notes: The different brain regions are seen in the left cerebellum posterior lobe (a), left middle temporal gyrus (b), right insula (c), right superior temporal gyrus (d), left middle frontal gyrus (e), bilateral anterior cingulate cortex (f), bilateral medial frontal gyrus (g), left superior frontal gyrus (h), right superior frontal gyrus (i), right precentral gyrus (j), left fusiform gyrus (k), and right inferior parietal lobule (l). The red areas denote higher ReHo brain regions, and the blue areas denote lower ReHo brain regions. P<0.05 for multiple comparisons using Gaussian random-field theory (z>2.3, cluster-wise P<0.05 corrected). Abbreviations: ReHo, regional homogeneity; ON, optic neuritis; HCs, healthy controls; R, right; L, left.

Figure 2

Means of altered ReHo between the ON group and HCs. Abbreviations: ReHo, regional homogeneity; ON, optic neuritis; HCs, healthy controls.

Figure 3

Correlations between the mean ReHo signal values of the different areas and the behavioral performances. Notes: The VEP amplitude of the right eye in the ON group showed a positive correlation with the ReHo signal value of the left cerebellum posterior lobe (r=0.701, P=0.011) (A), the right superior frontal gyrus (r=0.731, P=0.007) (B), and the left fusiform gyrus (r=0.644, P=0.024) (C). The VEP latency of the right eye in the ON group showed a positive correlation with the ReHo signal value of the right insula (r=0.595, P=0.041) (D). Abbreviations: ReHo, regional homogeneity; ON, optic neuritis; VEP, visual evoked potential.

Figure 4

ROC curve analysis of mean ReHo signal values for altered regional brain areas. Notes: Area under ROC curve for ReHo values =0.917 (95% CI 0.781–1, P=0.001) (A); area under ROC curve for ReHo values =0.958 (95% CI 0.887–1, P<0.001) (B). Abbreviations: ROC, receiver-operating characteristic; ReHo, regional homogeneity; CI, confidence interval.