Is Visual Snow a Thalamo-Cortical Dysrhythmia of the Visual Processing System - A Magnetoencephalogram Study (PDF)

Visual snow (VS) has been described as a unique clinical entity, which may occur with increased neuronal excitability. (1) Sensory information processing relies on the interactions between thethalamus and cortex. When hyperexcitability affects cortical networks, it can lead to thalamocortical dysrhythmias, resulting in tinnitus. (2) We hypothesize that VS is the visual manifestation ofthalamocortical dysrhythmia. Visual cortex gamma oscillations reflect cognitive processing and alpha oscillations are associatedwith thalamically generated pulses of cortical inhibition, altering information processing. (3) Thisoscillatory network activity is a characteristic property of the thalamocortical system.Therefore, we used Magnetocephalography (MEG) to record the visual cortex oscillatory dynamics,as a measure of possible thalamocortical dysrhythmia in VS patients and controls.