Bridget Riley, whose work was exposed in Paris a few months ago, is an artist who is worth mentionning to all optical illusions lovers since many of her works are based upon these phenomenons.
The research of some neuro-physiologists allowed to study the cerebral mechanisms inside those paintings and to determine that our brain needs some time to be tricked by optical illusions (the effect merely disappears if the painting is disclosed only shortly -during a split second- by an electronic flash light).
Source: ScienceBlogs