Disturbed spontaneous brain-activity pattern in patients with optic neuritis using amplitude of low-frequency fluctuation: a functional magnetic resonance imaging study

Abstract

Objective: To use the amplitude of low-frequency fluctuation (ALFF) technique to investigate the local features of spontaneous brain activity in optic neuritis (ON) and their relationship with behavioral performance.

Materials and methods: Twelve patients with ON (four male, eight female) and twelve age-, sex-, and education status-matched healthy controls (HCs) (four male, eight female) underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans. The ALFF technique was used to assess local features of spontaneous brain activity. Correlation analysis was used to explore the relationship between the observed mean ALFF values of the different areas and visual evoked potentials (VEPs) in patients with ON.

Results: Compared with HCs, patients with ON had significantly decreased ALFF values in the posterior and anterior lobes of the right cerebellum, right putamen, right inferior frontal gyrus, right insula, right supramarginal gyrus, right inferior parietal lobule, left medial frontal gyrus, left superior temporal gyrus, bilateral anterior cingulate/medial frontal gyrus, and bilateral precuneus, and significantly increased ALFF values in the posterior lobes of the left and right cerebellum, right inferior temporal gyrus, right inferior temporal/fusiform gyrus, left parahippocampal gyrus, left fusiform gyrus, left calcarine fissure, left inferior parietal lobule, and left cuneus. We found negative correlations between the mean ALFF signal value of the left parahippocampal gyrus and the VEP amplitude of the right eye in ON (r=-0.584, P=0.046), and a positive correlation between the mean ALFF signal value of the bilateral precuneus and the best-corrected visual acuity of the left eye (r=0.579, P=0.048) in patients with ON.

Conclusion: ON mainly seems to involve dysfunction in the default-mode network, cerebellum, and limbic system, which may reflect the underlying pathologic mechanism of ON.

Keywords: ALFF; fMRI; optic neuritis; resting state; spontaneous activity; visual evoked potential.

Figure 1

Significant differences in spontaneous brain activity between the ON group and HCs. Notes: The different brain regions are seen in the bilateral cerebellum posterior lobe, right cerebellum anterior lobe, right putamen, right inferior frontal gyrus, right insula, left medial frontal gyrus, left superior temporal gyrus, right supramarginal gyrus, bilateral anterior cingulate/medial frontal gyrus, bilateral precuneus, right inferior parietal lobule, left cerebellum posterior lobe, right inferior temporal gyrus, left parahippocampal gyrus, right inferior temporal/fusiform gyrus, left fusiform gyrus, left calcarine fissure, left inferior parietal lobule, and left cuneus. The red areas denote higher ALFF brain regions, and the blue areas denote lower ALFF brain regions (P<0.05 for multiple comparisons using Gaussian random-field theory (z>2.3, cluster-wise P<0.05 corrected). Abbreviations: ON, optic neuritis; HCs, healthy controls; ALFF, amplitude of low-frequency fluctuation; L, left; R, right.

Figure 2

Means of altered spontaneous brain activity between the ON group and HCs. Abbreviations: ON, optic neuritis; HCs, healthy controls; ALFF, amplitude of low-frequency fluctuation.

Figure 3

Correlations between the mean ALFF signal values of the different areas and the behavioral performances. Notes: The mean ALFF signal value of the left parahippocampal gyrus showed a negative correlation with the VEP amplitude of the right eye in the ON group (r=−0.584, P=0.046) (A), and the mean ALFF value of the bilateral precuneus showed a positive correlation with the left best-corrected VA (r=0.579, P=0.048) (B). Abbreviations: ALFF, amplitude of low-frequency fluctuation; VEP, visual evoked potential; ON, optic neuritis; VA, visual acuity.