Reflexive Eye Closure in Response to Cone and Melanopsin Stimulation: A Study of Implicit Measures of Light Sensitivity in Migraine
| Autor: | Edda B Haggerty, Geoffrey K. Aguirre, Eric A. Kaiser, Harrison McAdams, Brett Cucchiara, David H. Brainard, Aleksandra Igdalova |
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| Rok vydání: | 2021 |
| Předmět: |
Adult
Male Retinal Ganglion Cells medicine.medical_specialty genetic structures Photophobia Aura media_common.quotation_subject Migraine Disorders Visual Discomfort Audiology Retinal ganglion Medicine Contrast (vision) Humans media_common Blinking Reflex Abnormal business.industry Electromyography Intrinsically photosensitive retinal ganglion cells Rod Opsins medicine.disease Migraine Retinal Cone Photoreceptor Cells Female Neurology (clinical) medicine.symptom business Pupillometry Photic Stimulation Research Article |
| Zdroj: | Neurology |
| ISSN: | 1526-632X |
| Popis: | Background and ObjectivesTo quantify interictal photophobia in migraine with and without aura using reflexive eye closure as an implicit measure of light sensitivity and to assess the contribution of melanopsin and cone signals to these responses.MethodsParticipants were screened to meet criteria for 1 of 3 groups: headache-free (HF) controls, migraine without aura (MO), and migraine with visual aura (MA). MO and MA participants were included if they endorsed ictal and interictal photophobia. Exclusion criteria included impaired vision, inability to collect usable pupillometry, and history of either head trauma or seizure. Participants viewed light pulses that selectively targeted melanopsin, the cones, or their combination during recording of orbicularis oculi EMG (OO-EMG) and blinking activity.ResultsWe studied 20 participants in each group. MA and MO groups reported increased visual discomfort to light stimuli (discomfort rating, 400% contrast, MA: 4.84 [95% confidence interval 0.33, 9.35]; MO: 5.23 [0.96, 9.50]) as compared to HF controls (2.71 [0, 6.47]). Time course analysis of OO-EMG and blinking activity demonstrated that reflexive eye closure was tightly coupled to the light pulses. The MA group had greater OO-EMG and blinking activity in response to these stimuli (EMG activity, 400% contrast: 42.9%Δ [28.4, 57.4]; blink activity, 400% contrast: 11.2% [8.8, 13.6]) as compared to the MO (EMG activity, 400% contrast: 9.9%Δ [5.8, 14.0]; blink activity, 400% contrast: 4.7% [3.5, 5.9]) and HF control (EMG activity, 400% contrast: 13.2%Δ [7.1, 19.3]; blink activity, 400% contrast: 4.5% [3.1, 5.9]) groups.DiscussionOur findings suggest that the intrinsically photosensitive retinal ganglion cells (ipRGCs), which integrate melanopsin and cone signals, provide the afferent input for light-induced reflexive eye closure in a photophobic state. Moreover, we find a dissociation between implicit and explicit measures of interictal photophobia depending on a history of visual aura in migraine. This implies distinct pathophysiology in forms of migraine, interacting with separate neural pathways by which the amplification of ipRGC signals elicits implicit and explicit signs of visual discomfort. |
| Databáze: | OpenAIRE |
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