However, that may soon change as scientists from University of Washington (UW) and Howard Hughes Medical Center begin a closer analysis of the dimple-like structure, which can only be found in humans and other primates.According to study lead Dr Raunak Sinha, understanding how the fovea functions is crucial to developing methods to correct central vision loss and designing visual prosthetic devices.{{quote-A:R-W:450-Q: Understanding how the fovea functions is crucial to developing methods to correct central vision loss and designing visual prosthetic devices. }}“Diseases such as macular degeneration are much more debilitating than deficits in peripheral eyesight because of the importance of the fovea to everyday vision,” Sinha told science and technology news service phys.org.“When you look at a scene an arm’s length away the fovea subtends a field only about the size of your thumbnail. Your eyes undergo rapid movents to direct the fovea to various parts of the scene,” Sinha added, while explaining the fovea dominates visual perception and provides more than half of the signals from the eyes to the brain’s visual cortex.By using the novel research techniques, Sinha and his team have discovered the computational architecture and basic visual processing of the fovea are distinct from other regions of the retina. The results also help explain why central and peripheral vision have different qualities.According to Sinha, the low sensitivity is how we’re able to see motion in movies and flipbooks, and avoid the rapid flicker of a television signal when it refreshes.However, the flickering becomes apparent when we see the screen from the corner of the eye. Previous research on foveal output signals had indicated the perceptual specialisations of foveal vision originated mainly from the retina itself. However, Sinha’s team was able to reveal how the differences in the cellular and circuit mechanisms of foveal and peripheral retina could account for the differences in their perceptual sensitivities.Specifically, they found foveal midget ganglion cells processed input differently to their peripheral counterparts, as the dominant neural circuit in the fovea operated effectively independent of any sort of ‘braking’ at the synapse.Such a discovery is significant, as it shows the fovea works very differently at a cellular and circuit level to the other regions of the retina. “Determining the cellular origin of human perception is an important, but rarely realised goal in neuroscience and biology. Our results provide a simple explanation for a salient perceptual observation,” Sinha said.
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