Which brain networks misfire in visual snow?
In 24 VSS patients vs 24 controls, seed-based fMRI showed widespread hyper/hypoconnectivity across visual, attentional, and salience systems at rest and during visual input.
Source
Disrupted connectivity within visual, attentional and salience networks in the visual snow syndrome
Study at a glance
- Design
- Case-control — Seed-based fMRI connectivity in VSS vs matched controls at rest and with visual stimulus
- N
- N=48 · 24 VSS + 24 matched healthy volunteers
- Population
- Adults with visual snow syndrome and matched controls
- Outcome
- Between-group functional connectivity of visual/attentional/salience seeds
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Acquired whole-brain functional connectivity maps at rest and during a visual-snow-like stimulus using eight a priori unilateral seeds.
What they found
Altered visual-network connectivity, thalamus/basal ganglia–lingual links, visual motion network coupling to DMN/attention, plus reduced salience connectivity and V5–precuneus coupling during sensory input.
The limits
What it doesn't show
Connectivity differences are not proof of causal mechanism or a treatment target trial.
Key terms
- Visual snow syndrome (VSS)
- Neurological syndrome of continuous visual static and related symptoms.
- Functional connectivity
- Correlated fMRI activity between regions/networks.
- Salience network
- Network tracking relevant sensory/internal events; reduced connectivity here in VSS.
- Lingual gyrus
- Visual cortex region linked to thalamus/basal ganglia seeds.
- V5
- Visual motion area with altered precuneus coupling.
- Seed-based analysis
- Connectivity measured from predefined seed ROIs.
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VSS patients scanned:
Common questions
Sample?
24 VSS + 24 matched controls.
Conditions scanned?
Rest (blank screen) and visual-snow-like stimulus.
Seed count?
Eight unilateral a priori seeds.
Broad finding?
Widespread multi-network connectivity disruption.
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