Why doesn't the world go dark each time we blink? Researchers at University College London say it's because blinking turns off parts of the brain so we don't notice the change.

Blinking is difficult to study, but the scientists devised a clever experiment. They constructed a fiber optic light device that was placed in the mouth of a subject who wore lightproof goggles. When the device was turned on, light illuminated the retina of the eye through the roof of the mouth rather than through the eye! Therefore, the researchers could keep light on the retina even when a subject's eyes were closed.

Areas of Reduced Brain Activity

The scientists used functional magnetic resonance imaging to scan a subject's brain. When the retina was stimulated with the fiber optic light, the researchers found that blinking reduced activity in parts of the visual cortex, parietal cortex and prefrontal cortex. So, decreases in brain activity occurred even when the retina was stimulated with light.

These data should help us understand how we get an uninterrupted view of our surroundings. Life would be dangerous if the world went dark each time we blinked. Thankfully, our brains have a built-in system to keep this from happening.