Earlier quoted context omitted.
Correct!
Do we know anything about migraines based on their symptoms? As in, has there been any research where people with different migraine symptoms have been put in a scanner during the migraine to locate which parts of the brain display weird activity?
The migraine aura is rather well understood, it is the result of cortical spreading depression, a phenomenon where a "wave" of brain hyperactivity spreads in as a ring on the surface of the cortex, leaving a hypo-active zone in the middle.
It is possible to trigger the phenomenon by hurting the brain (e.g. sprinkle acid on a rat's brain, WP has a neat video: https://en.wikipedia.org/wiki/Cortical_spreading_depression) so we suppose that it is a defense mechanism in humans too, but we're not sure what causes them.
I've done research on migraine, 10 years ago, but I haven't kept up with the field. There are hypotheses, but no known cause for the headaches and associated symptoms.