A new study has revealed how visual masking, a phenomenon in which rapid succession of images leads to unconscious image processing, occurs in both humans and mice. This study highlights the role of the cortex in conscious perception and provides important insights into the brain’s visual processing mechanisms.
Delve into the mysterious optical illusions and science of visual masking.
Recent research published in natural neuroscience Visual masking is a phenomenon that plays an important role in how we perceive things, or rather how we don’t “see” them. This study not only revealed aspects of conscious perception in the brain, but also demonstrated that this phenomenon occurs in both humans and mice.
Visual masking occurs when a person does not consciously recognize an image because another image is displayed in rapid succession. For effective masking, the first image must appear and disappear quickly, followed by her second image within about 50 milliseconds.
Groundbreaking research in visual perception
Allen Institute researcher Dr. Sean Olsen and his colleagues have delved into the science behind this optical illusion and shown for the first time that it also occurs in mice. After training the mice to report what they saw, the researchers were also able to pinpoint the specific areas of the brain needed for the visual masking illusion to work.
“This is an interesting observation, that what exists in the world is not accurately reflected in your perception,” Olsen said. “Like other optical illusions, we think this tells us something about how the visual system works and, ultimately, the neural circuits underlying visual perception.”
Exploring the brain’s role in visual recognition
Scientists discovered this strange phenomenon in the 19th century, but why and how the human brain does this remains a mystery.
The study narrows down the parts of the brain involved in perceiving the world around us, said Dr. Christoph Koch, a Distinguished Fellow at the Allen Institute who led the study with Dr. Olsen and Dr. Sam Gale. Ta. , a scientist at the Allen Institute.
When a rain of photons hits our retina, the information follows a predetermined path from the eyeball through several different areas of the brain and into the highly-processed areas of the cortex, the wrinkled outermost shell of the brain. It ends with Previous research on visual masking has led scientists to believe that neurons in early parts of the brain, in the retina and its pathways, are activated even when a person is unaware that they are looking at an image. I know. In other words, your brain sees things without your knowledge.
From mouse to human: parallel recognition
To explore where unconscious sensations turn into conscious perceptions and actions, scientists first taught 16 mice to move a small mouse in the direction of a rapidly flashing image in exchange for a reward if they chose the correct direction. I trained him to spin a Lego wheel. The scientists then added different masking images on either side of the screen immediately after the target image. Adding a mask prevented the animal from performing the task correctly. This means that the animal can no longer recognize the original target image.
Visual masking had never been tested in mice before, so the research team had to create a task for mice, in which the images and the way they were displayed were different from those used in previous human studies. I meant that. To confirm that the optical illusion they showed to rodents was also relevant to us, the research team tested it on 16 people (using keystrokes instead of a wheel). It turns out that human perception (or lack thereof) and mouse perception of this particular visual masking illusion are very similar.
This result implies that conscious perception is occurring in the visual cortex or in higher regions of the cortex downstream. This is consistent with the general sentiment in the field that the cortex is the seat of conscious cognition in mammals, including us, Koch said.
Reference: “Visual cortex is required for posterior masking in mice” by Samuel D. Gale, Chelsea Stroder, Corbett Bennett, Stefan Mihalas, Christoph Koch, and Sean R. Olsen, November 13, 2023 Day, natural neuroscience.
DOI: 10.1038/s41593-023-01488-0
Source: scitechdaily.com
