A study from the Center for Neurocognitive Research (MEG Center) in Moscow provides new insight into the role of neuroplasticity in Visual Snow Syndrome (VSS).
Neuroplasticity refers to the brain’s ability to adapt and rewire itself based on experience and repeated stimulation. While this process is essential for learning, it can sometimes become disruptive—reinforcing abnormal patterns, such as persistent visual disturbances. In this study, researchers found that individuals with VSS show heightened plasticity in the primary visual cortex during repeated visual stimulation, suggesting that this altered brain adaptability may be a key mechanism underlying the condition.
Objective
While increased excitability in the brain’s visual regions has been suggested, the exact mechanisms remain unclear.
Researchers aimed to test two possibilities:
- The brain is unbalanced with activity, with too much excitation and not enough inhibition in the visual cortex.
- The brain might be adapting too strongly to repeated visual input, something known as disruptive neuroplasticity—which could make the “snow” effect more persistent.
To explore these ideas, researchers examined how the brain responds to repeated visual patterns and whether those responses differ in people with VSS compared to those without the condition.
Methods
Using magnetoencephalography (MEG), researchers recorded brain activity in 26 VSS patients and 27 healthy controls as participants viewed high-contrast circular patterns (gratings) that were either stationary or moving at different speeds.
This setup allowed the researchers to examine two things:
- How the brain reacts to stronger or faster visual input
- How brain activity changes over time with repeated exposure to the same visual patterns
They focused on a specific type of brain activity called gamma oscillations—high-frequency brain waves involved in visual processing and attention. To understand how the body’s nervous system might influence these brain changes, they also measured heart rate variability (HRV), which reflects the balance between stress (sympathetic) and relaxation (parasympathetic) signals in the body.
Results
The first key finding: both groups (VSS and controls) had similar responses to increasing visual stimulation. That means the excitation-inhibition (E-I) balance—the brain’s ability to regulate activity levels—was not significantly different in people with VSS.
The second finding: people with VSS showed a much stronger increase in gamma activity over time as the visual patterns were repeated. This suggests that their brains were adapting more intensely to the repeated input, a sign of heightened neuroplasticity.
Researchers also found that these increases in brain activity were linked to parasympathetic activity, which supports learning and adaptability. However, the strength of this effect did not depend on migraine history or how severe someone’s visual symptoms were, suggesting that this heightened plasticity is a core feature of VSS, not a side effect.
Conclusions
This is the first study to show direct evidence of heightened neuroplasticity in the visual cortex of individuals with VSS. These findings open up new possibilities for treatment. Therapies that regulate or retrain plasticity, such as neuromodulation (TMS), mindfulness-based therapy may help reduce symptoms. The repetition-related increase in gamma activity may also serve as a biomarker to track brain changes and evaluate the effectiveness of future treatments for VSS.
