Friday, 26 Dec, 2008 Science

Scientists Study a Sightless Man Unaware of Seeing


According to Swiss researchers, a local blind man could find his way through a maze despite the fact that he had no conscious feeling of seeing the things surrounding him. This phenomenon may be called second sight, but it certainly shows that human brain is able to process vision beyond ways that are currently understood in the field of science.

In a news release Beatrice de Gelder, who is a researcher at Tilburg University in the Netherlands and Harvard Medical School and the lead author of the study, said that visual skills feature mechanisms "for orienting and doing in the world rather than for understanding."

It is worth mentioning that researchers previously managed to discover a phenomenon known as "blindsight". Blindsight is a condition when blind persons can feel things around them. However, the current case is somewhat different as the man in the study could feel facial expressions, his brain showing signs of response to the emotions expressed on the faces of people around him. In addition, scientists noticed that the man had another ability which was not previously seen in a sightless. He was able to make his way though a maze.

The name and age of the man involved in the study remained undisclosed. Scientists said that he had two strokes that caused serious damage to the brain's visual centers. The authors of the study outlined that the man was completely blind since brain scans did not show any sign of activity in the brain's visual centers. However, in the December issue of "Current Biology", scientists wrote that the man passed the maze alone without any problem.

Scientists believe it is possible that the man used sound waves that helped him spot the position of the obstacles. According to Colin Ellard, associate chair of the department of psychology at the University of Waterloo in Canada, the current discovery reflects an earlier research that states the comprehension of vision involves several parts of the brain.

The researcher mentioned that this study provides additional information to the story on how human vision is organized in the brain. He says that the human ability to see involves a collection of different kinds of abilities. "Some can help us to understand, think and talk about what is in the external world, but others act to help us organize movements such as reaching or walking to targets," he said. Ellard added that the research outlines the fact that each of these abilities depends of on a specific part of our brain.

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