What causes migraines? Study of ‘brain blackout’ offers clues
What causes migraines? Study of ‘brain blackout’ offers clues
The blinding headaches are poorly understood — a mouse study suggests that the content of spinal fluid is a trigger for pain.
Interesting find, apparently protein levels in spinal fluid vary pretty drastically after an aural migraine (where the pain comes after aura).
They say the aura's are a reaction to total neural activity shutdown, but I have never consciously experienced that before an aura. I would expect to have deja vu after such an event
Brain blackout is kind of a dramatic word. I'm pretty sure the article is trying to refer to cortical spreading depression.
https://www.nature.com/articles/nrneurol.2013.192
This is a wave of decreased activity going across the brain. It's not the whole brain though, just a portion, and it tends to happen more often in the posterior brain than anterior. That's why visual and other sensory auras (posterior brain) auras are more common than motor/weakness auras (anterior brain). The visual aura itself is the spreading wave of decreased activity going across the brain. It happens in primary visual cortex, primarily dealing with lines and colors. Visual space is represented radially on the brain, so it can often be circular. The "fortifications" or lines on the edges some people see come from the fact that it's neurons that deal with line detection. Pain usually follows shortly after, but we aren't exactly sure how that works, and this article was posing a possible mechanism to help link these. The main bulk of the visual aura where it's grey, blurry, and indistinct is the decreased activity itself in the visual cortex. The area can get larger as the wave spreads.
Deja vu or jamais vu have been reported with migraines, though that's a very rare aura in comparison. It's all depending on what parts of the brain are involved with the cortical spreading depression for that migraine aura for that person in terms of what symptom will happen. Deja vu would be more temporal lobe. Temporal lobe is the most common localization for focal epilepsies. So deja vu as a symptom of a neurologic disease would more commonly be seen with seizures (focal seizures are sometimes called auras too, which gets confusing but are inherently different from what is happening in a migraine). But don't worry, most deja vu is nothing to worry about.
This image is kinda similar to my experience. It starts as a very small spot, often just blocking a letter or 2 of a word I’m reading, then spreads out in an arc or rough circle.
One interesting thing I’ve noticed as I get older (40s), is that if I’m moving over a distinct enough pattern, like a tile floor, the area inside the aura updates slower, or lags behind the surrounding (unaffected) area.
Also as I’ve gotten older, the pain following the aura has thankfully gotten lows severe, and sometimes doesn’t happen.
Very cool explanation, thanks! I think dramatization is the culprit here, introducing noise to the facts.
Your visualization of a type of visual aura is distinctly different from when I have them, which is very cool because another response tells us they do recognize it! Mine is more in the negative space around the 'aura' you shared, rotating on some pulse-timing (about half of the heart BPM ), counterclockwise (am a right-handed human), like a white bolt lightning-wave circling around the middle, covering about half the circle at any time. I'll try and recreate the visuals sometime.
Thanks again for elaborating on this subject, you expanded my understanding :-).
I never knew about how CSD spreads but that makes sense. I don't see artifacts with my auras. Generally everything becomes too bright and too loud all at once. I know I'm having a bad one if I start writing backwards (I will write the second letter of every word first) or slurring my speech. Thankfully I don't get super bad ones as much anymore.