How can a cartoon cause a seizure?

[Hadrian0117]

How can a cartoon cause a seizure? Electric Soldier Porygon, an episode of popular Japanese cartoon Pokémon caused over 700 children in Japan to have seizures. How can flashing lights cause seizures like that? Do you already have to have epilepsy?

[Squink]

Scientists probe cartoon seizures

The precise reason why a cartoon caused hundreds of children to have seizures may have been uncovered by experts.
…
But an Italian study, published in the March issue of Nature Neuroscience, found that children prone to a particular type of epilepsy nearly all had problems in one particular area of the brain.
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Photosensitive epilepsy is thought to affect between 0.5% and 0.8% of children aged between four and 14.

[rowrrbazzle]

Here’s a level-headed article about the whole thing: http://www.csicop.org/si/2001-05/pokemon.html

And Snopes has the clip and says no. http://www.snopes.com/radiotv/tv/seizure.htm