Introduction

The prognosis of visual acuity in optic neuritis (ON) patients varies greatly from individual to individual. Visual acuity (VA) was significantly restored by remodeling neurons of visual pathway in some patients after acute phase, but in the others, VA gradually declined until blindness.1 The relationship between visual prognosis and brain function alterations in ON patients remain unclear. The objective of this study was to investigate the potential links between brain activity amplitude alteration and VA, during a 3-year follow-up period.

Methods

A total of 43 ON patients and 44 healthy controls (HCs) were examined twice, with a 3-year interval. Based on the VA at the third year, ON patients were divided into two groups: 26 ON patients with good visual outcome (the 4m logarithm of the minimum angle of resolution (logMAR) VA<0.3), 17 ON patients with poor visual outcome (LogMAR VA>0.3). Resting-state fMRI collected to investigate the amplitude of low frequency fluctuation (ALFF) difference among the three groups. The relationship between ALFF in regions with significant group differences and VA was further explored.

Results

Significantly decreased mALFF were observed in visual cortex (left cuneus and left middle occipital gyrus), cognition-related areas (right paracentral lobule), and right anterior cingulate cortex, and bilateral middle temporal gyrus, left middle frontal gyrus in ON patients than HCs. While increased mALFF were occurred in several regions in the frontal and temporal lobes (P < 0.001, FDR corrected). We found positive correlations between VA and ALFF in bilateral middle temporal gyrus and significantly negatively related to ALFF in left middle frontal gyrus.

Discussion

In this study, we explored the brain activity amplitude alteration in patients with ON by using resting state fMRI data. Furthermore, we examined the relationships between brain activity amplitude alteration and VA. Significantly decreased mALFF were observed in bilateral middle temporal gyrus, left middle frontal gyrus in ON patients than HCs, which provided imaging evidence of cortical neuroplasticity. The positive correlations were found in bilateral middle temporal gyrus and significantly negatively related to ALFF in left middle frontal gyrus, which was suggested that these regions might play important role in the prognosis of visual acuity in ON.

Conclusions

From this follow-up study, we found the ALFF in middle temporal gyrus and middle frontal gyrus might play important role in the prognosis of visual acuity in ON. These findings provide important insights into the underlying neural mechanisms of ON.

Acknowledgements

Thanks for the MR Research of GE Healthcare for the support of MR technology in this paper.