I have noticed a connection over the past year that is new to me.
I've been having vividly bad dreams that seem to be connected to a migraine attack. They are not so much what I think of as nightmares (i.e. somebody trying to kill me, or being really scared, etc.) because they're more of the panic variety (i.e. things are one way one minute and then change so I'm terribly confused or can't find something or someone and I'm frantic to find them).
I seem to have the bad dreams and then when I wake from them, it's like my head is in a vice with the normal migraine symptoms - left side throbbing, nausea. These are severe migraines... and they're in full effect when I wake up. They're the kind that are actually kind of scary.
I didn't go to sleep with a migraine, so I don't know if it's the migraine that caused the bad dream or if it's the stress of the bad dream that caused the migraine. I did a little research and found that I'm not alone with this. Doesn't happen for all migraineurs, but others have experienced it too. Makes sense if it is indeed a brain disorder. I'll hope to learn more about this in the future.