A throbbing, pounding headache. Bright zigzagging lines across your field of vision. Sensitivity to light, lingering fatigue, disrupted sleep. While an incapacitating headache is one of the most common symptoms, a migraine can include any of these experiences. So what exactly is a migraine? And what causes it? Marianne Schwarz explores what we know— and don't know— about this complex disorder. Lesson by Marianne Schwarz, directed by Bálint Gelley, CUB Animation.