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So it works the same whether you have one or both eyes open? That's intriguing
by xtagon 8y ago
So it works the same whether you have one or both eyes open? That's intriguing
- pygy_ 8y agoYes, and you lose a hemi-field in both eyes if you have a stroke in the visual cortex on one side of the brain. Central vision is preserved though, because the fovea projects to both hemispheres.
- vanderZwan 8y ago> Yes, and you lose a hemi-field in both eyes if you have a stroke in the visual cortex on one side of the brain. In my case the aura of my migraines (that I thankfully only had during puberty) were limited to the left hemi-field. Which I guess suggests that the migraine was "centered" in the right brain hemisphere.
- pygy_ 8y agoCorrect!
- vanderZwan 8y agoDo 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?
- pygy_ 8y agoThe 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 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.