When you blink, the brain uses a special phenomenon to prevent it from getting dark. Neuroscientists have found out more about the specific process.
If we blink, it seems like we haven’t closed our eyes at all. Behind this is a special phenomenon in the brain, in which connections in the brain that react to visual impressions are interrupted shortly before the eyelids are closed.
On the one hand, this was discovered by British scientists who put a light source into the oral cavity of test persons during an experiment, which illuminated the retina from the inside when they blink. The retina was permanently illuminated with light, even when you blinked. At the same time, the scientists used functional magnetic resonance imaging to examine which regions of the brain were active during this time. The research group observed that the areas of visual perception were already faded out shortly before the eyelids were closed.
On the other hand, a research team from the University of Göttingen examined the responsible brain region in more detail.
A special curtain in the brain: that’s why it stays bright when you blink
Basically, the brain memory is responsible for the fact that the blinking happens almost unnoticed. Because part of the brain stores all previously seen impressions while we have briefly closed our eyes. When the eyes are opened again, it combines the old and new information into a fluid sequence of images so that the darkness is forgotten.
As scientists from Göttingen found out in a study with epilepsy patients in the USA, the region of the frontal lobe is particularly important for the process.
The test subjects were shown a grid pattern of dots, which they were asked to indicate whether they were arranged horizontally, diagonally or vertically in their opinion. They were then presented with another grid and asked to repeat the task. If the orientation was the same for the test subjects, it was because they were unconsciously using the brain image memory content of the first task. With the help of electrodes in the brain, the team was able to measure the activity of the nerve cells and finally localize the image memory.
Why do people blink at all?
Blinking is an important process that moisturizes and oxygenates the cornea. Each person blinks around ten to 15 times per minute, each for a tenth of a second. Although the eyelids are closed for a brief moment, it usually happens unnoticed and has little impact on perception.
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