Enhanced neural plasticity of the primary visual cortex in visual snow syndrome - evidence from magnetoencephalographic gamma oscillations

Sep 30, 2026

Uploaded by Aurelia

Visual snow syndrome is a neurological disorder marked by persistent visual disturbances and related symptoms, with mechanisms involving possible altered neuroplasticity in the visual cortex. This study uses magnetoencephalography to measure visual gamma oscillations in 26 patients and 27 controls during repeated high-contrast visual stimulation, manipulating drift rate and thus stimulation intensity. Group comparisons show no major differences in baseline gamma power or frequency. Both groups demonstrate time-dependent gamma changes, while patients show a steeper repetition-related increase, linked to parasympathetic-sympathetic balance indices, supporting atypically heightened activity-dependent plasticity.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Introduction

Background on visual snow syndrome and visual gamma oscillations

Study rationale and aims

[https://doi.org/10.1093/braincomms/fcaf505](https://doi.org/10.1093/braincomms/fcaf505) BRAIN COMMUNICATIONS 2026: fcaf505 | 1 BRAIN COMMUNICATIONS Enhanced neural plasticity of the primary visual cortex in visual snow syndrome: evidence from magnetoencephalographic gamma oscillations Elena V. Orekhova, 1 Anna M. Plieva, 1 Sophia M. Naumova,2 Tatiana S. Obukhova, 1 Andrey O. Prokofyev, 1 Anastasiia V. Petrokovskaia,3 Ada R. Artemenko4 and Tatiana A. Stroganova 1 Visual snow syndrome is a neurological disorder characterized by persistent visual disturbances and associated symptoms. Although the neural basis of the visual snow syndrome remains poorly understood, it may involve increased neuronal excitability and/or altered neuroplasticity in the visual cortex, which could, in turn, affect visual gamma oscillations. An altered excitation-inhibition balance is hypothesized to alter the modulation of gamma power and frequency by stimulation intensity, while maladaptive neuroplasticity may impact time-dependent changes in gamma power during repeated stimulation. To investigate potential alterations in the excitation– inhibition balance and neuroplasticity in visual snow syndrome, we used magnetoencephalography to record visual gamma oscillations in 26 patients with this disorder and 27 healthy controls. Participants were exposed to repeatedly presented high-contrast annular gratings, which were either static or drifting at varying speeds to systematically manipulate stimulation intensity. We also assessed heart rate variability during rest and repetitive visual stimulation to explore the relationship between time-dependent gamma changes and parasympathetic activation, which is known to promote activity-dependent plasticity. Our results showed no significant group differences in gamma power or frequency, nor in their modulation by drift rate, suggesting that the excitation–inhibition balance in the V1 area remains largely intact in visual snow syndrome. Both groups exhibited an initial brief decrease in gamma power followed by a sustained linear increase with stimulus repetition, likely reflecting activity-dependent plasticity. Heart rate variability parameters were comparable across groups, with the parasympathetic–sympathetic balance index correlating with repetition-related increase in gamma power, further supporting the link between time-dependent gamma changes and neuroplasticity. Notably, patients with visual snow syndrome exhibited a steeper repetition-related increase in gamma power, indicating atypically heightened activitydependent plasticity in this group. These findings provide the first experimental evidence suggesting that altered activity-dependent neuroplasticity plays a role in the pathophysiology of the visual snow syndrome. Furthermore, they identify repetition-related increases in gamma power as a potential biomarker of aberrant neuroplasticity, offering novel insights into the pathophysiology of the visual snow syndrome and potential avenues for targeted therapeutic interventions. 1 Center for Neurocognitive Research (MEG Center), Moscow State University of Psychology and Education, Moscow, Russia 2 National Research University Higher School of Economics, Moscow, Russia 3 Loginov Moscow Clinical Scientific Center, Moscow, Russia 4 Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, Russia Received March 29, 2025. Revised October 24, 2025. Accepted December 22, 2025. Advance access publication December 24, 2025 © The Author(s) 2025. Published by Oxford University Press on behalf of the Guarantors of Brain. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is prope

FAQs

What is visual snow syndrome, according to the study text?

It is a neurological disorder with continuous small flickering dots across the visual field, along with associated visual and non-visual symptoms such as photophobia and anxiety.

How did the researchers measure brain activity in the study?

They used magnetoencephalography to record visual gamma oscillations while participants viewed repeatedly presented high-contrast annular gratings.

What did the study find about gamma oscillations across patients and healthy controls?

There were no significant group differences in gamma power or frequency, but both groups showed repetition-related changes; patients had a steeper increase in gamma power, consistent with heightened activity-dependent neuroplasticity.

Sep 30, 2026

Uploaded by Aurelia