Scientists, for the first time, found the neural mechanism of sensing high-speed motion in faint light in the visual cortex of the brain.
Neurons in the visual cortex:
A group of neurons in the primary visual cortex (V1) of the brain are luminance-contrast cells that are responsive to a uniform patch of luminance and they prefer low spatial frequencies, high temporal frequencies, high motion speeds, and they respond strongly to luminance decrements.
These luminance-contrast cells are different from many other cells in primary visual cortex, which are either “luminance-only” – cells modulated by luminance only – and “contrast-only” – cells modulated by contrast only.
In the present study, researchers worked on the responses of cat V1 cells to the changing luminance and compared the speed preferences of luminance-contrast cells and contrast cells. They found that luminance-sensitive cells in cat V1 are important in motion processing under dim conditions of light as they prefer higher motion speeds than the contrast cells and a large number of these cells give strong responses to the decreasing brightness of light as compared to the increasing brightness of light.
Researchers are of opinion that these cells would be of particular help to the animals such as cats and other animals moving in low visibility environment such as in dark night and fog.
Yi Wang told SayPeople.com,
“To understand our results, I want to explain more point. Suppose that an animal is in a dark environment and there is a target having a luminance below the mean luminance of the dark environment is moving, the V1 cells sensitive to both the luminance decrements of large uniform patches and high motion speeds in the animal brain are capable of detecting the target. The luminance-contrast cells we revealed are of the capabilities. If have adapted to the dark environment, it is easier for these cells to detect the target.”
“We are further investigating the roles of these cells in the visual presentation of objects in the early visual cortex,” Yi Wang told SayPeople.com. Yi Wang is corresponding author of the paper.
“Using artificial stimuli with carefully designed parameters is the most effective method for in advancing our understanding of visual functions,” Researchers wrote in the paper.
This research can help in designing artificial vision, as Yi Wang told me.
Ran Li, Yi Wang (2013). Neural Mechanism for Sensing Fast Motion in Dim Light Scientific Reports DOI: 10.1038/srep03159