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Blind People 'Seeing': Human Echolocation / Blindsight

Dingo667 said:
Blindsight is quite well known and really has nothing to do with the visual cortex. Strangely enough, it seems that we can "see" with our whole body, not just the eyes. This seems to happen in the midbrain and was/is used by many lower [I don't like that word] animals.
Everyone has the ability. Try in complete darkness for someone to move their hand, you will be most likely to "feel/see" which direction it is going. Maybe that chap in the article has worked on that sense a little more.

We can only "see" with our eyes and brains, but decipheringscars was right, more or less, especially with the air pressure and heat.
Yes, that's right, blindfolding (absolute) would be a thorough test.
 
coaly said:
Dingo667 said:
Blindsight is quite well known and really has nothing to do with the visual cortex. Strangely enough, it seems that we can "see" with our whole body, not just the eyes. This seems to happen in the midbrain and was/is used by many lower [I don't like that word] animals.
Everyone has the ability. Try in complete darkness for someone to move their hand, you will be most likely to "feel/see" which direction it is going. Maybe that chap in the article has worked on that sense a little more.

We can only "see" with our eyes and brains, but decipheringscars was right, more or less, especially with the air pressure and heat.
Yes, that's right, blindfolding (absolute) would be a thorough test.


Erm no. Of course if we take the word "see" it is linked with eyes and the occipital lobes in which we process vision.
However vision is only that until it hits the retina, then it becomes noting ore than electric spikes, which are sent down the nerves, were they hit the relevant part of the brain, were they are "translated" into images inside our head. The occipital lobes and the eyes are working together.
Now, before we had eyes as we know, we could still "see", albeit very primitively. No high resolution, no colours but movement and sort of "shadows". This was/is processed in our midbrain, not the grey matter but our ancient part of the brain that can be found in almost all animals.
In order to "see" with this part, eyes are NOT necessary, it seems that we can "perceive" the input from even our skin and still "see" movement and "shadows". This is not my opinion, but proven scientifically.
I myself have had "blindsight" [on some other thread], where I could perceive shapes and my environment although my eyes were closed.
A few actually eye-blind people can also still perceive a sort of sight, which does not involve any of the neural pathways from the eyes.
So there... 8)
 
I know that there are animals which have light-sensitive cells in their skin. However I´m not under the impression that normal skin has an ability to detect light. Do you have a reference for this?
 
Xanatic_ said:
I know that there are animals which have light-sensitive cells in their skin. However I´m not under the impression that normal skin has an ability to detect light. Do you have a reference for this?



http://thefutureofthings.com/news/5479/ ... -skin.html


What I am on about is that the signals from touch "look" exactly the same as those from other senses once they are reaching the nerve, but depend on where they are received. This can easily lead to crossovers, such as is known by synastetic people who can see music or taste. To be able to "see" with your skin is absolutely not far fetched IMHO, as all it takes is for the sensory signal to reach the vison center in the occipital lobes instead of where it was supposed to go. Something that I can see absolutely happen in some blind people. Granted, it is a new idea but there have been quite a few blind people [as described in this thread], that could obviously register movement without their eyes. You can test this yourself, in a completely dark room, you can sort of tell in which direction someone's hand is waving even though you can't actually see...well it works for me.
 
Dingo667 said:
Xanatic_ said:
I know that there are animals which have light-sensitive cells in their skin. However I´m not under the impression that normal skin has an ability to detect light. Do you have a reference for this?


You gave a link to nothing but massive theory. Could you answer Xanatic's question please? With proper scientific references. Also, could you show me where you got the idea that we could see without eyes?
Dingo667 said:
Now, before we had eyes as we know, we could still "see", albeit very primitively. No high resolution, no colours but movement and sort of "shadows". This was/is processed in our midbrain, not the grey matter but our ancient part of the brain that can be found in almost all animals.
In order to "see" with this part, eyes are NOT necessary, it seems that we can "perceive" the input from even our skin and still "see" movement and "shadows". This is not my opinion, but proven scientifically.
show me the scientific proof for this also please. Cheers.
 
That link you gave talked about pit vipers and other animals. They do not see with their skin, they see with specialized photosensitive cells. That is likely all we had once, and that then developed into eyes with lenses and all. Snails still have "eyes" which aren´t much more than light-sensitive cells. However our skin cells are built differently, and also consist of dead cells.
 
OK, I'll try once more...
Of course our skin cells are build differently than photo sensitive cells, because they are skin cells. However, our skin also contains RECEPTORS

http://www.factmonster.com/images/ESCI351SKIN003.gif

[notice, not cells]. Receptors for pain, for temperature, for touch. When activated, they send an electric signal, called action potential along a neural pathway into our spine, where it is then send to the brain.

These electric signals look exactly the same as signals from your ears to your brain or from your muscles to your brain or from your eyes to the brain. They look absolutely identical! The only way we differentiate between hearing, sight, taste and so on is were these signals end up in the brain.

So if for example a sound signal would be received by the occipital lobe [in the grey matter, which is where sight is "perceived" [or decoded]], you would see music. Now, this is nothing outlandish as it happens in people with synasthesia.

http://www.lurj.org/article.php/vol2n1/synesthesia.xml


What I am saying is that it does not take too much imagination [especially not from any scientist that has worked in that field] to assume that the signals from the skin RECEPTORS [not cells] can also be received in a different place. So it is feasible that you could see touch for example.

Now, the skin also contains melanin [a chemical that reacts to UV light], [getting a tan is down to it], again we have here a possibility for skin to not only react to pressure [if something is passes by closely] etc but also to light.

Remember that ANY signal received from the outside world by our bodies, is absolutely identical in shape, so if a blind persons brain is growing a link to the skin receptors from the vision centre, hey presto you would see with your skin.

The other theory is that said signals go to the midbrain [or primitive brain, where sight has been processed throughout evolution].
Other beings do not even have brains [such as jelly fish] but nerve networks, they have no eyes but can still move and perceive light.

So "seeing" with your skin is no more outlandish than seeing taste [which exists]; and I truly believe that the proof [signed and published and everything] will be delivered soon [money, time and importance to make money from the finding allowing].
 
You're confused as to what synaesthesia is, essentially it's the interpretation of input from one type of receptor as input from another type, hench you can "taste" colour, or "see" sounds.

There aren't any photoreceptors in the skin, so while a synaesthete might experience a touch as distinct shade of blue, shining light of that colour on the skin won't evoke a image as there isn't anything to detect the blue light.

Melanin doesn't help either, melanocytes in the stratum basale aren't sensory cells, they produce melanin in response to UV-B, and other stimulants to protect the skin and the tissues beneath from UV damage. It doesn't have a sensory function in the eye either it's there as protection. Melanin doesn't provide any input into the nervous system.
 
Ok, what I am saying is that there needn't be any photo receptors in the skin for the kind of blindsight that I am trying to explain. The bit with melatonin was only to show that there are chemicals within our skin that react to light and hence "could" convey some sort of message to the brain without using photo cells/ receptors [only an idea].
I don't think I am misunderstanding synasthesia, it definitely is a "crossing" [bad wording] of nerve signals to a different part of the brain which starts when young and stems from one nervous pathway reaching two destinations. I have never heard of any other explanation.

May I just clarify that I do not 100% believe that blindsight is based on the explanations I give, I am just 100% happy that my explanation is very very likely!

I do believe in blindsight because many tests have been conducted, the question is now how is it possible rather then does it exist.
Not only that, but I have learned about blindsight and possible causes as far back as 1998, so it is not a new idea but was part of a module at my university course.
Obviously I can tell that rather than saying I might be right, it is far more fun to completely slaughter my idea. Well if anyone has a better one,
I stand behind what I am saying as I am very comfortable in my knowledge about the workings of the nervous system. In the same way that others will definitely know more about gardening, which I know f*ck all about.
 
I just requested some scientific evidence, that's all... because, as far as I'm concerned, there isn't any.
Could you still supply a link with the reference showing scientific proof, as stated in your post...
Dingo667 said:
In order to "see" with this part, eyes are NOT necessary, it seems that we can "perceive" the input from even our skin and still "see" movement and "shadows". This is not my opinion, but proven scientifically.
I'm not trying to get you to dig a hole.
 
Dingo667 said:
The other theory is that said signals go to the midbrain [or primitive brain, where sight has been processed throughout evolution].
Other beings do not even have brains [such as jelly fish] but nerve networks, they have no eyes but can still move and perceive light.

I think that is by far the most likely explanation of the case site in the OP. As others suggested earlier, a conclusive test would have been to see if the man could still do it blindfolded.
 
Oh, and on the subject of synaesthesia.

Once in my youth when I took LSD I saw a bloke on the telly with a hairstyle that was reminiscient of a wave, and you know what, it made me feel seasick.

But I was still docked!! :shock:


Explain THAT smartarses!

:p
 
Dingo667 said:
You can test this yourself, in a completely dark room, you can sort of tell in which direction someone's hand is waving even though you can't actually see...well it works for me.

Surely a completely dark room is a completely dark room, whether you're "seeing" with your eyes or your skin? If you're allegedly sensing movement in a completely dark room, it's not sight that's giving you that information.
 
drbastard said:
Dingo667 said:
The other theory is that said signals go to the midbrain [or primitive brain, where sight has been processed throughout evolution].
Other beings do not even have brains [such as jelly fish] but nerve networks, they have no eyes but can still move and perceive light.

I think that is by far the most likely explanation of the case site in the OP. As others suggested earlier, a conclusive test would have been to see if the man could still do it blindfolded.

To be a more rigourous test for any visual capabilities of the nerve receptors located in the skin, I'd suggest lights off would serve better than blindfolding.
 
Dr_Baltar said:
Dingo667 said:
You can test this yourself, in a completely dark room, you can sort of tell in which direction someone's hand is waving even though you can't actually see...well it works for me.

Surely a completely dark room is a completely dark room, whether you're "seeing" with your eyes or your skin? If you're allegedly sensing movement in a completely dark room, it's not sight that's giving you that information.

Yes it is sight, if; lets say you are blind and the pressure [from pressure receptors in the skin] of something or someone in the same room as you moves about, said pressure receptors will give a signal to your brain. Lets now say that you have always been blind or for a long time, said [pressure] signal will [amongst other destinations] also end up in your midbrain [as this is the central most ancient part of our brain], where primitive vision has always been decoded [and still is now, in ourselves and other animals], providing what I just said above, you would perceive that pressure in a very very basic way as if you saw it through your eyes!

Please let me make clear that the "image" would be no more than a kind of shadow and a sort of "idea" of movement.
Strange, I explained this to my husband yesterday and he not only agreed but came up with a similar explanation. But then he knows his way around neurosciences and is is fairly open minded.

And to all others who would like to get some "signed and stamped" scientific proof, no you won't get it.............................................yet!
[Frankly I don't think it is necessary either, as we are talking theories here and if the theory of a professor isn't good enough, what chances have I :roll: ]

I had enough of a good thread going ugly and end my involvement [for the time being] with a condensed version of my OPINION:

PRESSURE OR TEMPERATURE RECEPTORS = NEURAL PATHWAY INTO MIDBRAIN, were amongst other senses SIGHT is being processed.
NEW NEURAL PATHS through longterm blindness, also being processed, COULD EASILY be PERCEIVED as SIGHT. HOWEVER, the image would be VERY basic. NO COLOUR. JUST a HINT of an object and MOTION.
Chances of this being totally possible = 99.9%
NOT YET PROVEN but only a matter of time. In my opinion and that of some silly professor somewhere.
Good night, I'm having a chinese now! :headbutt:
 
Blind boy learns how to 'see' using dolphin technique
A blind boy has learnt how to "see" again after being taught a technique used by dolphins to detect where objects are.
Published: 6:55AM BST 30 Apr 2010

Jamie Aspland uses an 'echo location' technique, uttering high-pitch clicks with the sound then rebounding off surfaces to help guide him round obstacles.

The four-year-old, who was born without his sight, was taught the technique as part of a revolutionary new scheme in the US to help the blind.

His mother Deborah, 39, hailed the treatment after her son was able to walk unaided to the park for the first time and steered himself around a fence he was heading straight for.

Speaking after just three sessions of the therapy, she said: "It's changed our lives. The therapy has been a revelation.

"Since learning the skill we can walk to the park and Jamie no longer has to hold my hand. He even clicks to find out where the handrails are on our staircase before walking down unaided - it's amazing."

Jamie, from Ashford in Kent, has just completed his third session with US-based guru Daniel Kish - who lost his sight when he was just 13 months old.

As president of World Access for the Blind, Mr Kish has developed a system based on animal sonar to help humans form mental maps of their surroundings.

He copied the technique dolphins use to navigate their way through the murky depths - using high pitch clicks to penetrate objects and reflect off their internal structure.

Jamie is able to mirror that behaviour - which complements his use of a cane - by flicking his tongue against the roof of his mouth.

When the sound waves hit an object, it reflects the energy back to the ear to enable a blind person to decode its size, shape and distance.

The process is similar to what happens with vision in normal sighted people, who rely on patterns of returning light in order to actually see.

The money for Jamie’s £2,500 treatment was raised by well-wishers in his hometown who carried out a range of blindfolded activities to understand what life for Jamie is like.

He is among just a handful of children in the world being offered the treatment by globetrotting therapist Mr Kish, who is based in California.

He said: "Working with Jamie and his family was a terrific experience, and he was very responsive."

Mr Kish explained that echo location, or FlashSonar as he terms it, will eventually enable Jamie to detect buildings from a distance of 100 metres.

He said: "FlashSonar provides one with information of a fair amount of detail at distances of dozens of metres, depending on the circumstances.

"A tree may be detectable and recognized at 10 metres, while a large building may be detectable at 100 metres or more.

"It is literally like 'seeing' with dim flashes of light. In fact, neural scientists believe that the same parts of the brain used in visual processing are also being deployed for FlashSonar."

Ms Aspland, a mother-of-three, gave up her job as a tour operator to care for Jamie, his twin sister Rosie, who also has learning difficulties, and their autistic brother Kane full time.

She said she watched nervously after Jamie's first session when he approached a fence - but he managed to walk round it.

"We thought he was going to go straight into it. But he just went round it - I didn't think it would be possible. He was born blind but this therapy has given him a new lease of life."

http://www.telegraph.co.uk/news/newstop ... nique.html

Presumably this skill could be generalised by using echoes of other sounds in the environment as well, like a dog's bark, a door-bell, or even the sound of leather on willow! Having learned the basic technique so young, Jamie might develop amazing skills as he matures.
 
Re: Blindsight

rynner2 said:
Blind man navigates obstacle course using 'blindsight'
A man who was left completely blind by multiple strokes has been able to navigate an obstacle course using only his "sense" of where hazards lie.

.....

http://www.telegraph.co.uk/news/newstop ... sight.html

Now the Indie has an article on the same man:

Out of mind, out of sight: The blind man who can 'see' obstacles
Experiments on a blind man who can ‘see’ to avoid obstacles could have huge implications for the visually impaired
By Laura Spinney
Monday, 27 September 2010

In a darkened room, a blind man walks along a white line in the shape of a large ellipse.

He is taking part in an experiment which I have been invited to watch, at the University of Geneva in Switzerland. At one point, the scientist running the experiment, Beatrice de Gelder, asks me to stand on the white line, in the man’s path. I mustn’t move or make a sound. When he is about a metre away, he comes to a halt and asks: “Is somebody there?”

TN, as the blind man is known, suffered a stroke in 2003 which destroyed an area at the back of his brain that processes visual information: the primary visual cortex. The stroke affected only one hemisphere of his brain. What places TN in a category of his own, at least as far as the annals of science are concerned, is that about a month later he suffered a second stroke which wiped out the primary visual cortex on the other side of his brain. Suddenly, though his eyes were healthy, he became blind.

TN’s blindness is unusual, however, because he can still see in some situations, although he is unaware that he does so – a phenomenon known as blindsight. The most striking demonstration of this came two years ago, when de Gelder, a neuropsychologist at Tilburg University in the Netherlands and Harvard Medical School in the US, and neuropsychologist Alan Pegna of Geneva University and others, asked him to walk down a corridor which they had arranged like an obstacle course, having littered it with tripods, filing trays and boxes. He navigated his way successfully through the obstacles, though he said he saw none of them.

It’s well-known that hearing can become more acute in blind people, so to exclude the possibility that TN was relying on sound cues to negotiate his way through the obstacles the researchers asked him to repeat the experiment wearing earplugs. His performance didn’t change. “So it’s not auditory information that’s helping him,” says Pegna. “On the other hand, when we blindfolded him, he started bumping into the obstacles.”

etc...

http://www.independent.co.uk/news/scien ... 90303.html
 
I've recently read a magazine article about a young British boy being taught this skill, by an American who flew over especially to share his own personal skill. He accepts expenses, I believe.

The magazine was a Take a Break/Chat sort of thing which I take along to the gym to relieve the misery of the crosstrainer. I'll see if I can dig it out and post the details.
 
Fascinating subject. Good article covering some of the same ground and more:

The Blind Man Who Taught Himself to See
By Michael Finkel

The first thing Daniel Kish does, when I pull up to his tidy gray bungalow in Long Beach, California, is make fun of my driving. "You're going to leave it that far from the curb?" he asks. He's standing on his stoop, a good 10 paces from my car. I glance behind me as I walk up to him. I am, indeed, parked about a foot and a half from the curb.

The second thing Kish does, in his living room a few minutes later, is remove his prosthetic eyeballs. He does this casually, like a person taking off a smudged pair of glasses. The prosthetics are thin convex shells, made of acrylic plastic, with light brown irises. A couple of times a day they need to be cleaned. "They get gummy," he explains. Behind them is mostly scar tissue. He wipes them gently with a white cloth and places them back in.

Kish was born with an aggressive form of cancer called retinoblastoma, which attacks the retinas. To save his life, both of his eyes were removed by the time he was 13 months old. Since his infancy – Kish is now 44 – he has been adapting to his blindness in such remarkable ways that some people have wondered if he's playing a grand practical joke. But Kish, I can confirm, is completely blind.

He knew my car was poorly parked because he produced a brief, sharp click with his tongue. The sound waves he created traveled at a speed of more than 1,000 feet per second, bounced off every object around him, and returned to his ears at the same rate, though vastly decreased in volume.

But not silent. Kish has trained himself to hear these slight echoes and to interpret their meaning. Standing on his front stoop, he could visualize, with an extraordinary degree of precision, the two pine trees on his front lawn, the curb at the edge of his street, and finally, a bit too far from that curb, my rental car. Kish has given a name to what he does – he calls it "FlashSonar" – but it's more commonly known by its scientific term, echolocation.


Continued at length:
http://www.mensjournal.com/magazine/the-blind-man-who-taught-himself-to-see-20120504
 
Newly published research demonstrates that humans can learn echolocation skills with about 10 weeks of training.
Humans Can Learn How to 'Echolocate' in Just 10 Weeks, Experiment Shows

With enough training, most humans can learn how to echolocate, using their tongue to make clicking sounds, and interpreting the sounds of the echoes that come back, reflected from the surrounding environment.

In as few as 10 weeks, researchers were able to teach participants how to navigate obstacles and recognize the size and orientation of objects using the rebounding calls of their clicks. The experiment involved 12 participants who'd been diagnosed as legally blind during their childhood, and 14 sighted people.

Echolocation is a skill we usually associate with animals such as bats and whales, but some blind humans also use the echoes of their own sounds to detect obstacles and their outlines. Some use the tapping of a cane or the snapping of their fingers to make the necessary noise, while others use their mouths to make a clicking sound.

Despite how useful this skill can be, very few blind people are currently taught how to do it. Expert echolocators have been trying to spread the word for years now, and this new study suggests a simple training schedule is all that's needed. ...
FULL STORY: https://www.sciencealert.com/blind-and-sighted-people-can-learn-to-echolocate-in-as-few-as-10-weeks
 
Here are the bibliographic details and abstract from the open source article. The full article can be accessed at the link below.

Human click-based echolocation: Effects of blindness and age, and real-life implications in a 10-week training program
Liam J. Norman , Caitlin Dodsworth, Denise Foresteire, Lore Thaler
PLoS ONE 16(6) Published: June 2, 2021
https://doi.org/10.1371/journal.pone.0252330

Abstract
Understanding the factors that determine if a person can successfully learn a novel sensory skill is essential for understanding how the brain adapts to change, and for providing rehabilitative support for people with sensory loss. We report a training study investigating the effects of blindness and age on the learning of a complex auditory skill: click-based echolocation. Blind and sighted participants of various ages (21–79 yrs; median blind: 45 yrs; median sighted: 26 yrs) trained in 20 sessions over the course of 10 weeks in various practical and virtual navigation tasks. Blind participants also took part in a 3-month follow up survey assessing the effects of the training on their daily life. We found that both sighted and blind people improved considerably on all measures, and in some cases performed comparatively to expert echolocators at the end of training. Somewhat surprisingly, sighted people performed better than those who were blind in some cases, although our analyses suggest that this might be better explained by the younger age (or superior binaural hearing) of the sighted group. Importantly, however, neither age nor blindness was a limiting factor in participants’ rate of learning (i.e. their difference in performance from the first to the final session) or in their ability to apply their echolocation skills to novel, untrained tasks. Furthermore, in the follow up survey, all participants who were blind reported improved mobility, and 83% reported better independence and wellbeing. Overall, our results suggest that the ability to learn click-based echolocation is not strongly limited by age or level of vision. This has positive implications for the rehabilitation of people with vision loss or in the early stages of progressive vision loss.

FULL ARTICLE: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0252330
 
I wonder if there was an element of blindsight in this case.

In the 1920s, postman William Orr walked for miles every day along rural roads to deliver mail, despite the fact that he was registered as blind.

He was employed as a postal worker at Balnamore Mill in County Antrim. Despite his visual impairment, he regularly carried mail between the mill and the nearest town, Ballymoney, a journey of about two-and-a-half miles.

His life and livelihood is now being studied as part of a UK-wide history project, involving the Postal Museum in London and four English universities. The Addressing Health project is examining the health and mortality rates of postal workers during the Victorian and Edwardian eras - a period stretching from 1837 to 1910.

The research into William Orr is being led by Laura Newman from King's College London.

"William Orr is unusual because he did postal work but was not employed by the Post Office," she told BBC News NI. "Instead he was privately employed as a postman by Balnamore Mill. Despite this, we think his story is still worth telling because of what it can tell us about disabled people's experiences of doing postal work."

https://www.bbc.com/news/uk-northern-ireland-57762587
 
What bats and metal vocalists have in common

A new study published yesterday in the open access journal PLOS Biology finds that bats use distinct structures located in their larynx to make high-frequency calls for echolocation and lower-frequency social calls. And to make it even more musical, the structures used to make the low-pitched calls are similar to the ones death metal singers use in their growls.

https://www.popsci.com/environment/metal-bat-screaming/
Interesting. I always wondered how they can do all that growling and not get a sore throat.

Talking of bats, I saw an interesting feature on Daniel Kish who is blind and uses echolocation to get around. Amazing to see him riding a bike and correctly describing objects in his location just by using the sound of his vocal ‘clicks’.
 
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