Scientists have figured out why we rarely notice our own blinking. Our brains simply miss it, they say.
The quest for the new discovery began in the 1980s, when researchers found that visual sensitivity starts decreasing just before we blink. But what goes on in the brain remained a mystery.
In the new study, scientists put fiber-optic lights in the mouths of people. The lights were powerful enough to penetrate the roofs of their mouths and strike their retinas, where light is recorded. They wore goggles to block outside light.
When the test subjects blinked, the amount of light hitting their retinas didn't change. Activity in their brains was monitored by functional magnetic resonance imaging.
During blinking, brain activity was suppressed in areas that respond to visual input, the scientists report.
“Transiently suppressing these brain areas involved in visual awareness during blinks may be a neural mechanism for preventing the brain from becoming aware of the eyelid sweeping down over the pupil during a blink and the world going dark,” said Christopher Frith at the University College London.
The results are detailed in the July 26 issue of the journal Current Biology.