Human eyes have a built-in night vision mode, scientists believe. They found that for observation under the stellar and moonlight the retina changes both the "software" and the apparatus of photosensitive cells.

Retina chains, which were considered unchanged and programmed for specific tasks, can be adapted to different lighting conditions. The results, conducted by scientists from Duke University, show that reprogramming takes place in retina cells that are sensitive to movement. Even in better light, identifying the presence and direction of a moving object is the key to survival for most animals. However, motion detection with a single reference point does not work very well. Thus, vertebrate retinas have four types of motion-sensitive cells, each of which specifically responds to up, down, right or left movement. In humans, these directed neurons make up about 4% of the cells that send signals from the retina to the brain.

In the study of mouse retinas, performed under a microscope equipped with night vision lenses, in a very dark room, the researchers found that retinal cells, sensitive to upward movement, change their behavior in low light. Neurons will trigger when any movement is detected, not just up. When there is much less light, a weak signal from "up" -neurons in combination with a weak signal from any of the other directed cells can help the movement of the brain. Loss of motion perception is a common complaint in patients with severe vision problems. This finding of the adaptability of retinal neurons can help in the development of implantable retinal prostheses in the future.

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