Quirks & Quarks

Why you don't go momentarily blind when you blink

When we blink, the brain remembers what we're looking at and fills in the gap, researchers found.

When we blink, the brain remembers what we're looking at and fills in the gap

When this eye blinks, the brain will fill in the gaps in visual perception. (AFP/Getty Images)

Originally published on October 20, 2018.

When we blink you actually don't miss a thing, contrary to the popular adage about "missing it." We blink every five seconds on average, and new research is showing how our brain is able to fill in that brief gap when light doesn't reach our retina.

Caspar Schwiedrzik, from the German Primate Centre and the European Neuroscience Institute in Gottingen, led a team that investigated which parts of the brain were at work when we blink. 

The brain blink

The researchers knew from previous work using MRI that several brain regions, including the prefrontal cortex, were active during the formation of perceptual memory.

In their new work they were able to directly record brain activity of six people who had electrodes implanted in their brain in preparation for epilepsy surgery.

By simulating a blink using a display of connected images, they were able to see activity in the prefrontal cortex of the brain. This confirmed that perceptual memory is a key to what happens when we blink.

This representation of the brain's prefrontal cortex (green) shows the places where activity is measured when you blink. (Caspar M. Schwiedrzik)

In the blink of a eye

When a person closes their eyelids to blink, whatever they are looking at is retained in the prefrontal cortex as a memory.

It is then visually connected to what is seen when the eyelids open again. The prefrontal cortex actively calibrates the new input with the earlier visual data, creating a smooth and uninterrupted perception.

This enables us to perceive the world and navigate with more stability when we close our eyes for that brief moment.

And it all happens in the blink of an eye.