In search of the "I" function among visual processes; Contemplating His Character and PossibilitiesOliver Sacks wrote a case study about a sixty-seven-year-old painter who lost his color vision following a car accident. His vision was such that everything appeared to him like a black and white television screen. After numerous tests, his doctors found no problems with his eyes and concluded that he suffered from a rare form of brain dysfunction achromatopsia caused by damage to the visual cortex. Mr. I, as Oliver Sacks called him, remained conscious of the place that color should take. His color perception was replaced by acute acuity for shades of gray to a degree unknown to color-seeing people or congenitally color blind people. He felt uncomfortable because he only saw “horrible and disgusting” shades of gray where the color should have been. As an artist, his response to the loss of a fundamental faculty was to avoid social and sexual relations because everyone, including himself, looked like "animated gray statues." Food became disgusting because a black tomato suggested death to him. His awareness of where color should be due to all the shades and tones of gray was so distracting that he began trying to surround himself with black and white rice, black coffee, ... and even to redecorate certain parts of his house in black and white (1). Recent research on visual perception has revealed that color recognition requires at least three subsystems to function: physical receptors (the cones of the retina), wavelength-sensitive cells (apparently located in an area of the brain known as V1), and a higher order color generation mechanism (located in region V4). These three processes must work in harmony to produce the perception of color (1). Testing revealed that for Mr. I, V4's higher-order color generation mechanism did not work. Its other two processes worked perfectly. Using both of his normal vision processes, Mr. I was able to judge variations in gray by the comparative wavelength of reflected light without being able to see the actual color. Mr. I could also see textures and patterns that are normally obscured to us because of their integration into color. Oliver Sacks puts it this way: "His brain damage had made him conscious of, even trapped within, a strange intermediate state - the strange world of V1 - a world of abnormal and, so to speak, prechromatic sensations, which might not be classified as colored or colorless" (1).