Altered Brain Structure and Functional Connectivity of Primary Visual Cortex in Optic Neuritis

Area of Science:

• Neuroscience
• Neuroimaging
• Ophthalmology

Background:

• Optic neuritis (ON) involves brain adaptations, but mechanisms of functional connectivity (FC) and gray matter volume (GMV) changes remain unclear.
• Understanding these changes is crucial for diagnosing and treating ON, a condition affecting the optic nerve.

Purpose of the Study:

• To investigate the mechanisms underlying functional connectivity (FC) and gray matter volume (GMV) changes in patients with optic neuritis (ON).
• To compare brain imaging findings between single-attack ON, recurrent-attack ON, and healthy controls (HC).

Main Methods:

• Utilized structural MRI and resting-state functional MRI (RS-fMRI) on 51 single-attack ON patients, 45 recurrent-attack ON patients, and 49 HC.
• Performed FC analysis seeded in the primary visual cortex (V1) and whole-brain GMV analysis using voxel-based morphometry (VBM).
• Conducted correlation analyses between FC, structural MRI, and clinical variables like the Paced Auditory Serial Addition Test (PASAT).

Main Results:

• Positive correlations found between PASAT scores and V1 FC with the bilateral middle frontal gyrus.
• Negative correlation observed between disease duration and V1 FC with the left inferior parietal lobule.
• ON patients (both single and recurrent attacks) exhibited decreased FC in frontal and temporal lobes, right inferior occipital gyrus, right insula, and right inferior parietal lobule, alongside increased FC in the left thalamus compared to HC.
• No significant differences in brain GMV were detected among the groups.

Conclusions:

• ON patients display coexisting impairment and compensation in V1 area connectivity.
• These findings provide imaging evidence and insights into the neural mechanisms underlying optic neuritis.
• The study highlights the complex neural adaptations occurring in the brain following optic neuritis.