Functional Deficits and Structural Changes Associated With the Visual Attention Network During Resting State in Adult...

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Previous studies indicated impaired visual attention network activation in strabismic amblyopia (SA) using BOLD/fMRI.
• No prior research compared resting-state fMRI activation and functional connectivity (FC) in key visual attention network regions between SA, anisometropic amblyopia (AA), and healthy controls (HCs).

Purpose of the Study:

• To compare resting-state fMRI metrics including gray matter volume (GMV), amplitude of low frequency fluctuations (ALFFs), regional homogeneity (ReHo), and FC within the visual attention network (V1, IPS, FEFs) across SA, AA, and HC groups.
• To investigate correlations between corrected visual acuity (cVA) and MRI findings in amblyopic eyes.

Main Methods:

• Resting-state fMRI was performed on SA (n=20), AA (n=20), and HC (n=21) participants.
• Analysis included GMV, ALFF, ReHo, and FC in the visual cortex (V1), intraparietal sulcus (IPS), and frontal eye fields (FEFs).
• Correlation analysis between LogMAR cVA of the amblyopic eye and MRI results was conducted.

Main Results:

• SA participants showed greater GMV but lower ALFF in V1 compared to AA and HC groups.
• Both SA and AA groups exhibited higher right FEF and IPS activation (zALFF, zReHo) than HCs, but lower left FEF activation.
• SA showed lower activation in both V1 areas than HCs. Higher FC was observed in right FEF-left V1, right FEF-right V1, and right FEF-right IPS pathways for SA and AA groups compared to HCs.

Conclusions:

• Resting-state visual attention network function is impaired in both SA and AA.
• The findings suggest that slower saccade activation times in amblyopic eyes lead to the dominant eye controlling visual attention network activation.
• Right hemisphere FEF activation in SA and IPS activation in AA during rest highlight hemispheric differences in visual attention deficits.