Why Do Some Still Images Trigger Seizures?
By now, most people are aware of strobe lights’ ability to induce photosensitive epileptic seizures. A troll allegedly gave a journalist a seizure with a tweet. An episode of Pokemon sent almost 700 Japanese children to the hospital. But still images can cause seizures, too, and scientists are just now starting to figure out how that happens.
There’s still a ton we don’t know about seizure triggers, since there isn’t a reliable way to test them in humans or animals. A team of researchers from the University Medical Center Utrecht wanted to know what was going on in the brain that might help them better understand why some still images trigger seizures and others don’t.
“One particular type of brain wave… called a gamma oscillation, is particularly strongly driven by certain kinds of visual patterns,” Dora Hermes, lead author of a correspondence published today in Current Biology, told Gizmodo. A black and white bar pattern can induce these gamma oscillations in the brain’s visual cortex, the image processing part of the brain — and in an epileptic brain, the researchers hypothesise that the oscillations are linked with seizures.