Behavioral measures of cortical hyperexcitability assessed in people who experience visual snow

Abstract

Objective: To determine whether visual perceptual measures in people who experience visual snow are consistent with an imbalance between inhibition and excitation in visual cortex. Methods: Sixteen patients with visual snow and 18 controls participated. Four visual tasks were included: Center-surround contrast matching, luminance increment detection in noise, and global form and global motion coherence thresholds. Neuronal architecture capable of encoding the luminance and contrast stimuli is present within primary visual cortex, whereas the extraction of global motion and form signals requires extrastriate processing. All these tasks have been used previously to investigate the balance betw..