Visual resting-state network in relapsing-remitting MS with and without previous optic neuritis.

Area of Science:

• Neuroscience
• Radiology
• Ophthalmology

Background:

• Multiple Sclerosis (MS) is a demyelinating disease affecting the central nervous system.
• Visual pathway involvement is common in MS, even in normal-sighted patients.
• Optic neuritis (ON) is a frequent manifestation, potentially impacting visual function and brain connectivity.

Purpose of the Study:

• To investigate functional connectivity within the visual resting-state network (V-RSN) in normal-sighted relapsing-remitting MS (RRMS) patients.
• To compare V-RSN connectivity between RRMS patients with and without a history of ON.
• To explore correlations between V-RSN alterations and clinical/neuro-ophthalmologic variables.

Main Methods:

• Recruited 30 normal-sighted RRMS patients (16 without ON, 14 with ON) and 15 healthy controls (HCs).
• Performed neuro-ophthalmologic evaluations (visual field testing, RNFL thickness).
• Acquired structural and resting-state fMRI (RS-fMRI) data; analyzed V-RSN connectivity using ICA and gray matter atrophy using VBM.

Main Results:

• RRMS patients exhibited reduced bilateral peristriate visual cortex connectivity compared to HCs.
• ON-MS patients showed increased extrastriate cortex connectivity (right lateral middle occipital gyrus) versus nON-MS.
• ON-MS patients also displayed reduced right inferior peristriate cortex connectivity, correlating with prior ON episodes. V-RSN changes were independent of gray matter atrophy.

Conclusions:

• Normal-sighted RRMS patients demonstrate significant V-RSN functional disconnection.
• RRMS patients with prior ON undergo complex V-RSN reorganization, including enhanced extrastriate visual area connectivity.
• Findings suggest V-RSN alterations are a key feature of MS, even without overt visual impairment, and are modulated by optic neuritis history.