Scientists have figured out how long visual events should last for the brain to notice. A study by scientists from the American National Eye Institute (NEI) is published on the website of Medical Xpress.
Visual perception – the body’s ability to understand visual changes – depends on how the eye and brain work together. The signals generated in the retina pass through the nerve fibers of the ganglion cells into the brain. In the studied mice, 85% of the ganglion cells of the retina are connected to the brain region by an upper collicle. It provides most of the early visual processing in these animals. However, in primates, most of the information is analyzed by the visual cortex, but 10% of the retinal ganglion cells are still connected to the superior collicle.
The researchers concluded that when the brain processes visual information, the evolutionarily conservative region, the superior colliculus, notifies other areas of the brain that an event has occurred. This process takes about 100 milliseconds – just so much the brain needs to understand that an event has occurred.
Scientists came to this conclusion due to the inhibition of this area of the brain in mice – as part of the experiment, they blocked access to parts of the brain at different times in order to establish how many seconds should pass for a reaction to an event.
“One of the most important aspects of vision is the rapid detection of important events, especially those that can threaten the body. Our study shows that it depends on visual processing in the midbrain, and not just on the visual cortex”.
Richard Krauslis, senior author of the study.
Understanding the early stages of visual processing can be important in exploring conditions in the brain that affect perception and visual attention. These data can help treat diseases such as schizophrenia and attention deficit hyperactivity disorder.