User:Hartleyjs/sandbox

My name is Joshua Hartley, and I am on Wikipedia for a Psychology Course.

An edit to the "Research Section"

Dr. Cowey wrote extensively about patient GY and the tests he underwent to provide further evidence Blindsight is functionally different than conscious vision. To do this GY was not only asked to discriminate between whether or not a stimulus was presented, but he was asked to state the opposite direction of travel for that stimulus. That is to say if the stimulus was traveling upward, he was to indicate it was moving downward, and if it was moving downward he was to indicate that it moved upward. GY was able to do this with incredible accuracy in his left visual field, however he consistently stated the wrong direction of travel in his deficit visual field. This indicated that though GY was aware of the movement, he was not able to apply the rule as stated by the researchers to his observations.

Evidence in Animals

In 1995 Dr. Cowey published a paper entitled, “Blindsight in Monkeys.” At the time Blindsight was a little proven phenomenon that was believed to be caused by damage due to stroke. However patients were rare and it was hard to separate the areas responsible for the condition from other damage retained. In this experiment Cowey attempted to show monkeys with lesions in or even wholly removed striate cortexes also suffered from Blindsight. To do this he had the monkeys complete a task similar to the tasks commonly used on human patients with the disorder. The monkeys were placed in front of a monitor and taught to differentiate between trials where either an object in their visual field or nothing is present when a tone is played. Since Blindsight causes people to not see anything in their right visual field, if the monkeys registered blank trials, or trials in which no object was presented, the same as trials in which something appeared on the right, then they would have responded the same way as a human with Blindsight.Cowey hoped this would provide evidence for his claims that the striate cortex was key to the disorder, and he did find that the monkeys did indeed preform very similar to human participants.

Also that year Cowey published a second paper, “Visual detection in monkey’s with Blindsight.” In this paper he wanted to show that monkeys too could be conscious of movement in their deficit visual field despite not being consciously aware of the presence of an object there. To do this Cowey used another standard test for humans with the condition. The test is similar to the one he previously used, however for this trial the object would only be presented in the deficit visual field and would move. Starting from the center of the deficit visual field the object would either move up, down, or to the right. The monkeys preformed identically to humans on the test, getting them right almost every time. This showed that the monkey’s ability to detect movement is separate from their ability to consciously detect an object in their deficit visual field, and gave further evidence for the claim that damage to the striate cortex plays a large role in causing the disorder.

Several years later Cowey would go on to publish another paper in which he would compare and contrast the data collected from his monkeys and that of a specific human patient with Blindsight, GY. GY’s striate cortical region was damaged through trauma at the age of eight, though for the most part he retained full functionality, GY was not consciously aware of anything in his right visual field. By comparing brain scars of both GY and the monkeys he had worked with, as well as their test results, Cowey concluded that the effects of striate cortical damage are the same in both species. This finding provided strong validation for Cowey’s previous work with monkeys, and showed that monkeys can be used as accurate test subjects for Blindsight.

A cautionary note however, Cowey also concluded that further research would have to be completed before conscious vision could be said to be located in the striate cortex. Though damage to the region does lead to deficit vision in the right visual field this does not necessarily mean we have located a brain area for conscious vision.

Cowey, A., & Stoerig, P. (1995). Blindsight in monkeys. Nature, 373(6511), 247-249.

Stoerig, P., & Cowey, A. (1997). Blindsight in man and monkey. Brain, 120(3), 535-559.

Cowey, A., Alexander, I., & Stoerig, P. (2008). A blindsight conundrum: How to respond when there is no correct response. Neuropsychologia, 46(3), 870-878. doi:10.1016/j.neuropsychologia.2007.11.031