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BOB HIRSHON (host):
Mapping hallucinations in the brain. I’m Bob Hirshon and this is Science Update.
The images people see when they hallucinate may actually be the structure of their own brains. This according to mathematician Jack Cowan of the University of Chicago. He says that all visual hallucinations resemble just four basic geometric patterns that form when the brain’s visual cortex is disturbed.
JACK COWAN (University of Chicago):
Things like tunnels and funnels and spirals and honeycomb patterns and cobwebs.
He says the neural connections in the brain’s visual cortex have a strip-like crystalline structure. The spherical retina of the eye twists this structure into the four basic geometric patterns we perceive as hallucinations.
People have obviously been seeing these images for at least 20,000 years, because if you look at rock art and cave paintings you can see the imagery there as well.
I’m Bob Hirshon, for AAAS, the science society.