Blinking Reduces Brain Activity

October 12, 2005

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.

Did you Know?
  • We blink 10 to 15 times each minute (more than 5 million times each year!).
  • Each blink lasts 0.10 to 0.15 seconds (100 to 150 milliseconds).

Reference and more information:
  1. Bristow, D., Haynes, J.D., Sylvester, R., Frith, C.D. and Rees, G., Blinking suppresses the neural response to unchanging retinal stimulation, Curr Biol., 15:1296-1300, 2005.
  2. The Retina - Neuroscience for Kids
  3. Wellcome Department of Imaging Neuroscience, University College London

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