Neuropsychologists Show Some Blind People 'See' With Their Ears

[thinker_jeff]

ScienceDaily (Mar. 17, 2011) — Dr. Olivier Collignon of the University of Montreal's Saint-Justine Hospital Research Centre compared the brain activity of people who can see and people who were born blind, and discovered that the part of the brain that normally works with our eyes to process vision and space perception can actually rewire itself to process sound information instead.

 

 

The research was undertaken in collaboration with Dr Franco Lepore of the Centre for Research in Neuropsychology and Cognition and was published March 15 in the Proceedings of the National Academy of Sciences.

 

The research builds on other studies which show that the blind have a heightened ability to process sounds as part of their space perception. "Although several studies have shown occipital regions of people who were born blind to be involved in nonvisual processing, whether the functional organization of the visual cortex observed in sighted individuals is maintained in the rewired occipital regions of the blind has only been recently investigated," Collignon said. The visual cortex, as its name would suggest, is responsible for processing sight. The right and left hemisphere of the brain have one each. They are located at the back of the brain, which is called the occipital lobe. "Our study reveals that some regions of the right dorsal occipital stream do not require visual experience to develop a specialization for the processing of spatial information and are functionally integrated in the preexisting brain network dedicated to this ability."

 

The researchers worked with 11 individuals who were born blind and 11 who were not. Their brain activity was analyzed via MRI scanning while they were subjected to a series of tones. "The results demonstrate the brain's amazing plasticity," Collignon said. Plasticity is a scientific term that refers to the brain's ability to change as a result of an experience. "The brain designates a specific set of areas for spatial processing, even if it is deprived of its natural inputs since birth. The visually deprived brain is sufficiently flexible that it uses "neuronal niche" to develop and perform functions that are sufficiently close to the ones required by the remaining senses. Such a research demonstrates that the brain should be more considered as a function-oriented machine rather than a pure sensory machine."

 

The findings raise questions regarding how this rewiring occurs during the development of blind new born babies. "In early life, the brain is sculpting itself on the basis of experience, with some synaptic connections eliminated and others strengthened," Collignon noted. Synaptic connections enable our neurons, or brain cells, to communicate. "After a peak of development ending approximately at the age of 8 months, approximately 40% of the synapses of the visual cortex are gradually removed to reach a stable synaptic density at approximately the age of 11 years. It is possible that that the rewiring occurs as part of the maintenance of our ever changing neural connections, but this theory will require further research," Collignon said.

 

Collignon's study received funding from the Fondation de l'Hôpital Sainte-Justine, the Fonds de la recherche en santé du Québec, the Canadian Institutes for Health Research, the Natural Sciences and Engineering Council of Canada, and the Fonds de la Recherche Scientifique of Belgium.

 

Link: http://www.sciencedaily.com/releases/2011/03/110316104123.htm

 

 

 

[Marat]

Gregory's book, 'Eye and Brain,' has some interesting discussions of the perception and thinking of people born blind who were later given sight by an operation on the optic nerve. Some of these people were quite skilled at geometry while they were blind but could not recognize standard geometrical figures and shapes when first shown them after gaining the ability to see. It raises the interesting question of how they were modelling the appearance of these objects so that they could reason about them in a sophisticated way, even though their models obviously did not permit them to build conceptual bridges to the visual representations before them.

[thinker_jeff]

Gregory's book, 'Eye and Brain,' has some interesting discussions of the perception and thinking of people born blind who were later given sight by an operation on the optic nerve. Some of these people were quite skilled at geometry while they were blind but could not recognize standard geometrical figures and shapes when first shown them after gaining the ability to see. It raises the interesting question of how they were modelling the appearance of these objects so that they could reason about them in a sophisticated way, even though their models obviously did not permit them to build conceptual bridges to the visual representations before them.

Yes, I read the similar case from another book. If I remember correct, it was The Story of Psychology by Morton Hunt.

[tar]

Marat,

 

Interesting to me is the statement that the blind person with the repaired optic nerve did not recognize the geometric shape when FIRST shown it. I assume that this means they soon fit together the auditory perceptions with the new visual ones, as they moved and looked and heard around. Thus updating their model of the world, with their new insights. For instance, perhaps certain soft objects that they had never touched, looked bigger than they had heard, and certain hard objects smaller, or farther away than they had imagined from their echoes.

 

Regards, TAR2

[thinker_jeff]

Marat,

 

Interesting to me is the statement that the blind person with the repaired optic nerve did not recognize the geometric shape when FIRST shown it. I assume that this means they soon fit together the auditory perceptions with the new visual ones, as they moved and looked and heard around. Thus updating their model of the world, with their new insights. For instance, perhaps certain soft objects that they had never touched, looked bigger than they had heard, and certain hard objects smaller, or farther away than they had imagined from their echoes.

 

Regards, TAR2

Marat's explanation does have supported studies.

 

Your assumption is based on normal human brain without sensory defect. Unfortunately brains have a great deal of plasticity, which causes the brain of the blind person to map the neural network abnormally.

[tar]

abnormally?

 

Thinker_jeff,

 

Abnormally, but maybe not "incorrectly".

 

I am assuming that since the blind person understood geometry, they "knew" what a circle was, and a square, and what a straight line was, and so forth. Not unlikely they could hold a ball in their hands, and move their hands around it and tell you it was a sphere. Or walk in a straight line.

 

The world we internalize is already correct, and stays correct, regardless of which aspects of it we discover and add to our model of it. Presumably the blind person we are talking about still had the senses of taste, smell, touch, and hearing, and could explore the world, and be told about the world, and internalize many of the characteristics of the world, enough to build a sensible model of it, that fit together, the way the model of a "normal" person's would.

 

Not surprising that a brain deprived of one of the senses it had evolved to work with, would develop "abnormally", but much of the apparatus evolution bestowed upon that blind person, in terms of the functioning of memory and the ability to sense their own body, and its position within the space and time it found itself in, remained intact. Perhaps, given the way that persons brain rewired and repurposed functional units of the brain, their brain developed "normally" exactly the way it could, under the circumstances.

 

But you are right. I have no studies.

 

Regards, TAR2

[Marat]

I located a source which discusses these issues, though the results seem contradictory, with blind patients restored to sight sometimes being able to recognize what objects are without touching them, while at other times they have to feel them first to identify them and make the correlation to their blind experience of them.

 

One case reported describes a life-long blind man of 52 who was restored to sight by a cornea transplant. The experimenters report:

 

"We showed him a simple lathe (a tool he had wished he could use) and he was very excited. We showed it him first in a glass class, at the Science Museum in London, and then we opened the case. With the case closed, he was quite unable to say anything about it, except that the nearest part might be a handle (which it was -- the transverse feed handle), but when he was allowed to touch it, he closed his eyes and placed his hand on it when he immediately said with assurance that it was a handle. He ran his hands eagerly over the rest of the lathe, with his eyes tight shut for a minute or so; then he stood back a little, and opening his eyes and staring at it said: 'Now that I've felt it I can see.'"

 

-- R. L Gregory, 'Eye and Brain' (New York: McGraw-Hill) 1972, pp. 197-198

 

It seems from this that the blind person has learned to acquaint himself with things via touch and then apply this tactile information to his ability to organize his experience, label things, and identify them linguistically, but that he has still not learned how to apply the knowing process to visual material. With other objects, in contrast, he could label them correctly just from sight, such as block capital letters, which he had learned to identify by touch in blind school, but which he had not learned by sight. Perhaps the difference between his experience with block capital letters and the lathe was in the degree of spatial complexity each exhibited -- though letters can be quite complicated? More likely he had just had more practice with block capitals in blind school than with lathes, so he still seemed to have difficulty using visual information creatively to put together a coherent idea of a new thing. This seems supported by the fact that he could not identify lower-case letters, even though he knew upper-case letters by both touch and sight.

[tar]

Marat,

 

And the fact that the lathe he had touched was probably a different style than the one in the museum. (Lower case lathe.)

 

And sometimes,(to turn the table on the question), you hear a sound behind you, and can not identify it, without turning around and seeing what is making the sound.

 

Perhaps the 52 year old would not have to turn around to know what just made the sound.

 

Regards, TAR2

[thinker_jeff]

I am assuming that since the blind person understood geometry, they "knew" what a circle was, and a square, and what a straight line was, and so forth. Not unlikely they could hold a ball in their hands, and move their hands around it and tell you it was a sphere. Or walk in a straight line.

 

The world we internalize is already correct, and stays correct, regardless of which aspects of it we discover and add to our model of it. Presumably the blind person we are talking about still had the senses of taste, smell, touch, and hearing, and could explore the world, and be told about the world, and internalize many of the characteristics of the world, enough to build a sensible model of it, that fit together, the way the model of a "normal" person's would.

 

Not surprising that a brain deprived of one of the senses it had evolved to work with, would develop "abnormally", but much of the apparatus evolution bestowed upon that blind person, in terms of the functioning of memory and the ability to sense their own body, and its position within the space and time it found itself in, remained intact. Perhaps, given the way that persons brain rewired and repurposed functional units of the brain, their brain developed "normally" exactly the way it could, under the circumstances.

It just happened that a new study was published on Nature Neuroscience, which answers your question very well.

 

Abstract: http://www.nature.co...ll/nn.2795.html

 

"The Newly Sighted Fail To Match Seen With Felt"

 

"Would a blind subject, on regaining sight, be able to immediately visually recognize an object previously known only by touch? We addressed this question, first formulated by Molyneux three centuries ago, by working with treatable, congenitally blind individuals. We tested their ability to visually match an object to a haptically sensed sample after sight restoration. We found a lack of immediate transfer, but such cross-modal mappings developed rapidly."

Edited June 3, 2011 by thinker_jeff

[tar]

thinker_jeff,

 

I did not subscribe to the article, but I got its drift. The important part to me, is that the newly sighted person rapidly mapped the visual information to what they already knew the world was like.

 

The line I am pursuing, in my general muses since November is an attempt to understand language in all its aspects. I wish to understand the "meaning" that is held in words, and I attempting to understand this from neurological, evolutionary, physical points of view as well as linguistic, and philosophical ones.

 

There are many things we understand in a metaphorical way, we draw analogies, fill in patterns, take ratios, put one thing in the place of another, and so forth. But the basic building blocks of what we think, are the patterns we have internalized, of the outside world, and made a part of us. My theory is that we build an analog model of the outside world, that we hold within us, with that which we sense.

 

The unsighted person had access to the outside world, moved about in it, learned about its objects and the relationship between the objects. He/she knew many things about the objects, just not what they looked like.

 

The analogy I use for a thought experiment is to outfit myself with a pair of goggles hooked to a computer and a hand held device that "sees" in whatever frequency range you set it too. You could set it for radio wave and "see" what they look like (with the lower frequencies depicted in your goggles as red and the higher frequencies of the range you set, depicted as purple). The important thing is that there is a one to one correspondence, depicting in an analog fashion, the frequencies you cannot sense to frequencies you can. Perhaps your device could pick up magnetic fields, or compression waves, or detect certain chemical signatures...in any case you could "see" what the patterns and distributions and interactions, "looked" like. Then consider, instead of goggles you had a mat with tiny "pixel" points that could vibrate and extend and heat that you would put your hands on, or place on your belly or you back or somewhere where the "points" of sensation were close. If you assigned in an analog fashion, low frequency to slow and cool, high frequency to fast and hot, and amplitude to extension (pressure), you could "feel" what something "looked" like.

 

Point is when you "first" set the modality and the range, you will experience something new, but rapidly "learn" to map it to your model of the world. And then the new aspects you experience will be part of your model.

 

Regards, TAR2

[thinker_jeff]

I did not subscribe to the article, but I got its drift. The important part to me, is that the newly sighted person rapidly mapped the visual information to what they already knew the world was like.

You've missed the most important point of the research, which is in the title - "The Newly Sighted Fail To Match Seen With Felt". The process about "cross-modal mappings developed rapidly" was after "a lack of immediate transfer" which means newly sighted person cannot know the world by looking without touching.

Unfortunately I don't have right to send you a copy of the paper.

[tar]

thinker_jeff,

 

Yeah, I have a tendency to look at things the way I want to see them. Not very scientific.

 

But still, the learning process did occur.

 

Someone could say something sensible to me in plain Arabic...and even though it might be a sensible true statement about the real world...I wouldn't be able to recognize it. I couldn't map it to the world I know. I would have to learn what sounds meant what.

 

I don't see it as a surprising finding that a blind person would not be able, by some magic suddenly switched on program, to immediately coordinate his/her visual perceptions, with the world he/she had up to that point learned about, in terms of touch and sound information. It seems quite sensible that they would have to learn what goes with what.

 

It seemed to me, from the abstract, that that is what was found in the study.

 

What am I missing?

 

Regards, TAR2

 

as I understand it, when a human baby first opens its eyes, they "see" two separate blurry images, upside down and backward

 

We learn to focus near and far, put the images together, and put things right in terms of up and down and left and right, as we move around the world and learn about it, and our relationship to it.

[thinker_jeff]

Alright. If we understand the conclusion of the research in the same way, I will give my point about this discussion, which is the answer to the question you asked initially.

 

abnormally?

 

Thinker_jeff,

 

Abnormally, but maybe not "incorrectly".

The neural network of the blind person has been mapped abnormally, which is working incorrectly when the person becomes a newly sighted one.

[tar]

I guess I have sort of a philosophical problem with that assessment. Abnormal is a given, since normal brain development includes input from normally functioning eyes. But incorrectly is a different concept. To be incorrect you would have to assume that there is one correct way for the brain to develop. This is obviously not the case, since we all learn different things, and each of us has a unique model of the world that we hold.

 

Plus, the fact that human brains have much in common with each other, speaks to the fact that such an arrangement as we all possess has been very successful at internalizing the world, building a analog model of it, and being able to imagine it different ways, by working with this model.

 

If the brain is plastic, and able to learn about the world, by some repurposing of the normal use of certain structures, this may indeed be correct. It is still the already correct outside world being correctly internalized. Just not in the normal way.

 

I like to leave open the idea that our brains are an analog reflection of reality. I do not think we are "other than" reality. We are made up of it. As such, even an abnormal brain, is still correct in many ways.

 

But still, maybe I am missing your point. But if I am, then maybe there is an assumption that is being made, in terms of "how a brain should be", that I do not understand the logical basis to. If a brain should be a certain way, then how did it ever evolve? And is it done evolving?

 

Regards, TAR2

Edited June 10, 2011 by tar