When certain parts of an image are perceived as different colors, even though there is no difference, we experience an optical illusion. The effect occurs due to the fact that the brightness or color of the background changes, as a result of which the perception of the object in the foreground changes. Brain scientists have long studied how the brain deceives itself, and so far two explanations have emerged. According to one of them, the hoax is easily created even during a low level of nervous activity, and no previous experience is needed to believe it. On the other hand, higher brain functions explain the creation of illusions that go beyond previously acquired knowledge about light and colors.
Former computer scientist In the form They simulated human vision and found that optical illusions do not require high-level visual processing or prior experience, and work without them. Only basic neural processing is responsible for the illusory effect of images.
Cortical processing of visual information begins in the primary visual cortex, which is located at the back of our skull, in the occipital lobe. This is called the V1 field (it was called Brodmann area 17). Different types of cells in the visual cortex are responsible for specific areas, for example, one for spatial orientation (which interprets the shape of objects, letters, and numbers), another for spatial orientation (which interprets the shape of objects, letters, and numbers), direction of movement (connected to V1 cells), and another Responsible for the simultaneous vision of the two eyes, which is achieved thanks to the microscopic neurons of V1.
Thus, the visual cortex consists of several layers of neurons, some of which are responsible for basic functions, and others for more complex visual processing. new In the study Note that there is connectivity between several neural layers, V1 and V2, during optical illusion processing. This revealed that consciousness is a top-down process, meaning that our brain interprets the environment experientially, based on previous experiences, and does not rely solely on visual stimuli. If the process was directed from the bottom up, the brain would rely only on visual images for processing.
The mouse illusion
After computer tests, they have now investigated how the brain's self-deception works in living people. Laboratory vision research in mice has focused on the neon color illusion, which involves patterns of thin lines, but some lines are a different color than others. During the study, mice were shown images containing a neon green playing optical illusion and a set of similar but non-illusory patterns. Meanwhile, the neural activity of the rodents' brains was measured using implanted electrodes. They also looked at how clearly they saw the illusion images, whether their pupils were dilated or constricted.
It turns out that they changed, narrowed or widened in response to the lighter or darker shades appearing in the illusory image, just as people's eyes perceive changes in light. The essence of the image shown in the experiment was that neon-colored lines are perceived by the brain as connected shapes and circles.
The image of the non-existent circle appears brighter than the lines surrounding it. The interplay between colors and lights causes sensory disappointment.
When light hits our eyes, electrical signals travel through nerves to the visual cortex. Visual data processing is done here.
V1 neurons respond to both illusory and non-illusory images, but the response to illusory images comes more slowly, because feedback is required from higher visual areas, and feedback is required. In the new study, they also tried to inhibit the activity of feedback neurons in mice, and it turned out that V1 neurons responded less to images of an optical illusion.
This means that a higher level feedback loop is needed to detect the illusion.
Therefore, studies on mice did not produce the same results as the analysis of the computer model, according to which it is sufficient to see current images to detect optical illusions, and no previous experience is needed, and it is sufficient to rely only on visual stimuli, as the brain combines the perceived images together (in a false image), and does not He draws it from the past. But it may not be possible to completely separate my past and present experiences. Past experiences influence present processing, and cognition can result from a combination of the two.
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