Looking for the :: Biology Essays Research Papers

Looking for the I Function among the Visual Processes Contemplating its Character and PossibilitiesOliver Sacks wrote a case study about a sixty-seven year venerable painter who lost his twine vision as a pull up stakes of a car accident. His vision was such that everything appeared to him as a minacious and smock TV screen. After numerous tests his doctors could find nothing rail at with his eyes and concluded that he had a rare cerebral disfunction form of achromatopsia caused by visual cortex damage. Mr. I, as Oliver Sacks c all(prenominal)ed him, retained an awareness of where likeness should be. His color perception was replaced with a sharp acuity for tones of color in-headed to a degree not known to color-sighted people or congenital color-blind people. He felt uncomfortable because he saw besides awful and disgusting shades of grey where the color should have been. As an artist, his response to the loss of a fundamental faculty was to shun social and sexual inter course, because everyone, including himself, looked like animated grey statues. Food became disgusting because a drab tomato suggested death to him. His awareness of where the color should be because of all the grey shades and tones was so distracting that he began to try to surround himself with black and white-white rice, black coffee, ... even redecorating parts of his house in black and white (1).Recent research into visual perception has revealed that color recognition requires a minimum of three sub-systems to be functioning Physical receptors (the retina cones), wavelength-sensitive cells (apparently located in an area of the brain known as V1), and a higher locate color generating mechanism (located in the V4 region). These three processes need to work in harmony to yield the perception of color (1).Tests revealed that for Mr. I, the higher order color generating mechanism in V4 was not working. His other 2 processes were operating perfectly. Because of his two normal vis ion processes, Mr. I was able to judge variations in grey by the comparative wavelength of the reflected light without being able to see the existent color. Mr. I could also see textures and patterns that are normally obscured to those of us because of their embedding in color. Oliver Sacks puts it this wayHis brain damage had made him privy to, indeed trap him within, a strange in- between state-the uncanny world of V1-a world of unreasonable and, so to speak, prechromatic sensation, which could not be categorized as either color or colorless (1).