
When the primary visual cortex processes sequences of complete images and images with missing elements -- here vertical contours -- it "subtracts" the images from each other (the brain computes the differences between the images). Under certain circumstances, the neurons forward these image differences (bottom) rather than the entire image information (upper left). [...]
"We have now demonstrated that the visual cortex suppresses redundant information and saves energy by frequently forwarding image differences," similar to methods used for video data compression in communication technology. The study was published in Cerebral Cortex. [...]
If these individual images were presented at 33Hz (30 milliseconds per image), the neurons represented complete image information. But at 10Hz (100 milliseconds), the neurons represented only those elements that were new or missing, that is, image differences.