Long-range inhibitory mechanisms in the visual system are impaired in migraine sufferers

• Published in: Cephalalgia 2012-10, Vol.32 (14), p.1071-1075
• Main Authors: Wagner, Doreen, Manahilov, Velitchko, Gordon, Gael E, Storch, Peter
• Format: Article
• Language: English
• Subjects: Adult; Afterimage - physiology; Contrast Sensitivity; Female; Humans; Male; Membrane Potentials; Migraine with Aura - physiopathology; Migraine without Aura - physiopathology; Neurons - physiology; Photic Stimulation; Scotoma - etiology; Scotoma - physiopathology; Visual Cortex - physiopathology; Visual Perception - physiology; Young Adult
• ISSN: 0333-1024; 1468-2982
• DOI: 10.1177/0333102412455712

Background: After viewing dynamic noise surrounding a homogeneous grey patch (artificial scotoma), observers perceive a prolonged twinkling-noise after-image within the unstimulated area. It has been suggested that noise-stimulated neurons induce a long-range inhibition in neurons within the artificial scotoma, which generates a rebound signal perceived as twinkling noise following noise termination. We used this paradigm to test whether migraineurs have enhanced excitability or weakened inhibition. Methods: Twinkling-noise duration was measured in 13 headache-free volunteers, 13 migraineurs with aura and 13 migraineurs without aura. Results: The durations of the after-image were significantly shorter for both migraine groups compared to controls. Discussion: Enhanced excitation of noise-activated neurons in migraineurs would produce stronger rebound activity and longer after-image durations, while weakened inhibitory mechanisms would diminish the rebound activity and shorten the after-image durations compared to control subjects. The results suggest that cortical inhibitory mechanisms might be impaired in migraineurs with and without aura.