Hemodynamic responses related to intrinsically photosensitive retinal ganglion cells in migraine

• Published in: Neuroscience research 2020-11, Vol.160, p.57-64
• Main Authors: Yamakawa, Masahiko, Tachibana, Atsumichi, Tatsumoto, Muneto, Okajima, Katsunori, Ueda, Shuichi, Hirata, Koichi
• Format: Article
• Language: English
• Subjects: fNIRS; Hemodynamic response; Hemodynamics; Humans; ipRGCs; Light; Melanopsin; Metamerism; Migraine; Migraine Disorders; Photic Stimulation; Retina; Retinal Ganglion Cells; Rod Opsins
• ISSN: 0168-0102; 1872-8111
• DOI: 10.1016/j.neures.2019.11.011

•Hemodynamic responses in the visual cortex were measured to investigate the contribution of ipRGCs in migraine under visual stimulation.•Statistically significant changes in fNIRS signals dependent on stimulation intensity applied to ipRGCs were observed in patients with migraine.•No such changes were observed in healthy participants.•ipRGCs, in addition to photometric values related to cones, may be associated with migraine. To clarify whether photoreception of intrinsically photosensitive retinal ganglion cells (ipRGCs) is related to migraine, we investigated the relationship between hemodynamic responses related to neural activity and visual stimulation of ipRGCs. It has been established that photoreception in ipRGCs is associated with photophobia in migraine. However, the relationship between visual stimulation of ipRGCs and hemodynamic responses in the visual cortex has not been clarified. Hemodynamic responses in the visual cortex were measured using functional near-infrared spectroscopy (fNIRS) as signals reflecting changes in oxygenated and deoxygenated hemoglobin concentrations. Different types of visual stimulation generated by a metamerism method were applied to the peripheral field of the eye of patients with migraine (N = 20) and healthy participants (N = 21). The stimulation intensity on the retina was controlled using an artificial pupil. In the primary visual cortex of patients with migraine, statistically significant changes in fNIRS signals dependent on visual stimulation intensity applied to ipRGCs were observed (p < 0.01), while no such changes were observed in healthy participants. These results reveal that visual stimulation of ipRGCs projecting to the primary visual cortex is involved in hemodynamic responses in patients with migraine, suggesting that ipRGCs, in addition to photometric values related to cones, are associated with migraine.