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Blind Man Navigates Obstacle Maze Unaided
iammani writes "The NYTimes runs a story about a blind man (blind because of a damaged visual cortex) successfully navigating an obstacle maze, unaided. Scientists have shown for the first time that it is possible for people who are blinded because of damage to the visual (striate) cortex can navigate by 'blindsight,' through which they can detect things in their vicinity without being aware of seeing them."
Blindsight is 20/20.
There is a video of a blind person on youtube who seems to be able to navigate just like a regular person through the use of echoes. He carries and uses a clicker to make sounds.
There is a group which teaches the blind to locate objects through echoes.
Without a working visual cortex, nothing from the eyes enters the brain. At all.
It would be really nice if hypothesis and biology worked like that, where biology followed our hypotheses, but it doesn't. It would be interesting to see an fMRI, or see if he could navigate the maze with earplugs or some way of throwing off air pressure. Assuming it can't possibly be his eyes connecting to some other part of the brain simply because textbooks say the eyes connect only to the visual cortex is not a safe conclusion.
"Without a working visual cortex, nothing from the eyes enters the brain. At all."
Whoopsie. Apparently you didn't know about the body of work showing that there are connections between the retina and subcortical areas as well as the striate cortex. Of course, if you'd read the article, you would have noticed they mentioned that.
Yes, I read your other comments, including the one where you claim to have read the article. To summarize: you don't think it's possible... because .
Doctors remain baffled at the inability the majority of Slashtards to read and comprehend a simple article summarizing a medical experiment, despite apparently functioning visual systems. "They just wouldn't quit insisting that the subject of the experiment used echolocation to navigate the obstacles in the hallway, no matter how clearly and explicitly the article explained that the possibility had been ruled out," say baffled researchers. "We don't think their brains are wired correctly."
There's only one way to be certain: repeat the experiment.
I would suggest having the blind man and an average-sighted man separately walk down a very well-lit corridor with randomly positioned (i.e., changing every iteration) obstactles 10 times, recording the amount of time each takes and the number of collisions. Reduce the amount of lighting by some increment and repeat the experiment. Continue reducing lighting until total darkness is achieved.
If the blind man is truly navigating by blindsight, both his course times and collision rates should roughly scale positively with those of the sighted man and inversely to the light levels. But then, that would be using the scientific method like the international team of neuroscientists in TFA (whom you are accusing of incompetence) did, so of course you wouldn't believe it...
Maybe the problem is that TFA tried to make the science more approachable to people, but you obviously don't understand a single thing about blindsight. This is nothing new at all. In layman's terms, the participant still experiences visual sensation but not visual perception -- they can still see, but they are unaware of it. What is significant in this case is the extent of the damage to the visual cortex. The sensory compensation of congenitally blind people is incredible, but this is an entirely different phenomenon.
Sight doesn't "occur" in the eyes, but there are a number of subcortical structures the information passes through before it gets to the visual cortex. Which, oddly enough, is exactly what they say in TFA, which you claim to have read. They specifically say that the "visual areas of the brain" did NOT "light up", so I have no clue what you're babbling about.
The entire point of the article is that the extent of subcortical visual processing (which we are unconscious of) is greater than most people realise. So feel free to read it again and appreciate what is actually a well-established neurological phenomenon.
From bugmenot.com:
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No existe.
I call it being able to hear the "sound shadows" of objects, because that's really what they are - an object blocks sound, and that blockage is projected to the ear. With a good cane, I can navigate around tables, columns, and even position myself relative to peoples' voices to keep myself from running into them. It's quite amazing what you can tell with a good hallway, and a constant sound source (soda/vending machines are good). For example, an open, echoy space usually means a stairwell.
Also, randomness ... the first time I went to post, my screen reader was very sluggish and crashed. I guess Slashdot hates blind Linux users.
Bene Gesserit?
Sorry, I'm reading the book Paul of Dune which I just got as a Christmas present. Couldn't help myself... :)
You don't know what you don't know.
Isn't it obvious or am I missing something here??
Blindfold the blind man and repeat the experiment with/without the blindfold. That will tell if vision is being used in any way.
Do you mean this kid?
http://uk.youtube.com/watch?v=qLziFMF4DHA
(That's part 1 of the documentary. Links to the other parts are in the info box.)
Incredible stuff, he rides a bike and everything!
What isn't explained though is how he's playing video games?
I suggest a double blind test.