The Blind Brain: Part 1 of 2

Saturday 24 March 2007 1:00PM

A completely blind artist paints perfect replicas of the world he's never seen. An Indian child born with cataracts miraculously gains full visual capacity at age 12. People born blind experience their 'seeing' mind in different ways, and are helping scientists challenge the dogma of a brain rigidly hard-wired for vision. And, Zoltan Torey, blinded 56 years ago in an industrial accident, shares his own wildly vivid experience of an 'inner eye'.


Natasha Mitchell: And welcome to All in the Mind on ABC Radio National. Natasha Mitchell with you, great to have your ears.

And radio is of course the great festival of the ear. But a question for you; if your sight was taken from you, what would you most miss seeing?

Zoltan Torey: Of course sunsets, sunrises, the mountains, the sea, so much beauty, so much beauty, Natasha, honestly, and most people are completely blasé. You know, they really walk past miracles daily. I think I would truly, truly appreciate the wonderful world that surrounds me and us, and just life and the world and the universe is a totally wondrous thing.

Pawan Sinha: One might wonder how would a brain that has never received visual information, how might it imagine a scene, the spatial layout of a scene? Or how might a blind person dream? Do their dreams have any what we would consider visual content? Peering into what is the subjective experience of a blind person, how is it that a blind person experiences the world, or if you ask them to imagine being in a room, exactly what is it that they are imagining? I would love to find out.

Natasha Mitchell: Today on the show—blindness and the mind—the first of two programs exploring how the blind brain 'sees' and senses the world. This week, challenging the dogma about how malleable or plastic the contents of our skull really are.

In 1951 Zoltan Torey was just 21. He'd escaped the Soviet occupation in Hungary, arrived in Australia alone, and was studying dentistry at university.

But a shocking industrial accident robbed him of his eyes, an exploding vat of acid blinding him permanently and fused his vocal chords.

His life since has been channelled into two quite extraordinary books, a memoir called Out of Darkness, and another, The Crucible of Consciousness, which is recognised as a robust and unique contribution to the study of the conscious mind, so much so it's about to be reissued by MIT Press.

What do you remember of that last experience of what you formerly knew as sight, as vision?

Zoltan Torey: Well, Natasha, I remember absolutely everything. In fact, over the years my memory has only sharpened. Evidently the visual cortex, far from going blank and atrophying, it has picked up in acuity, and it is now totally under my command, so I virtually live in a visual space that I constantly produce myself. It is not really a canvas that I'm looking at, it is really visual space, so that I am—in the middle of which I find myself. So if I turn around, for example, I see what's behind me, and as I turn my head around in the room where I am, so I orientate into the objects and furniture which I'm facing. It's a completely technicolour, textured, visual world which apparently I continuously produce.

Natasha Mitchell: Zoltan Torey's experience of an inner eye...phenomenal. More in a moment.

A huge proportion of your brain—around a third—is dedicated to vision. Perhaps not surprising, given how much of what we think and do is mediated by what we see. The whole back section of your brain containing your visual cortex is involved. But what happens when you're born blind? Does this part of your brain then sit idle, twiddling its neuronal thumbs, or is it co-opted in unexpected ways?

Joining me from the studios of Harvard University are two guests. First meet Pawan Sinha, a computational neuroscientist with a difference. Associate Professor in Neuroscience at MIT, he heads a unique humanitarian and scientific project, helping people who are born blind later regain their sight, and studying them as they do.

A rare population in the West, but in India the rates of children born with cataracts are higher, because of infections during pregnancy and lower vaccination rates.

Pawan Sinha: Absolutely. An ophthalmologist in Italy, Alberto Valvo, estimated that fewer than 15 such cases have been studied in any detail over the past millennium, but in India it turns out that there is still a population of children who are treatably blind. And it was upon discovering this population of children that I decided to launch Project Prakash.

Natasha Mitchell: And you're working with an extraordinary population of people under the banner of what's called Project Prakash, 'prakash' being the Sanskrit word for 'light', I gather. Tell me about the Indian woman who you've written about most recently. You called her by her initials, SRD.

Pawan Sinha: We met her in 2003, we were in a clinic in Gujarat, that's a state in western India, and she had come there to get her daughter checked. Her daughter was born with congenital cataracts, she was about six years old at the time. But we found that the mother herself had a really remarkable history; she had been blind with cataracts until the age of 12 and had then been treated, and at the time we met her she was 32 years old. So she had had 20 years of post-operative vision. We decided that this was a really unique opportunity to study how much the brain can learn if given an extended period of time after a really protracted amount of blindness.

Natasha Mitchell: Because essentially she had the cataracts up until age 12, so there was no visual stimulus, or very little, for the first 12 years of her life, is that right?

Pawan Sinha: Indeed. So she had light sensitivity but that was all, so she could tell whether she was in a bright room or a dark room.

Natasha Mitchell: What did you find surprising in her case? Because you'd assumed that she would find it very difficult to teach the brain how to see again after that extended period of blindness.

Pawan Sinha: Yes, we went in not expecting anything at all. We didn't think she would have any significant visual capabilities, but when we tested her on a whole battery of fairly complex visual tasks which included things like complex shape matching or visual memory or face recognition, what we found was that her abilities were remarkably well developed. So that's what surprised us the most; how 'normal' she looked, even after having had this very long period of blindness.

Natasha Mitchell: Are there tasks that she didn't do so well at?

Pawan Sinha: There are. One of the tasks was gaze perception. Even though she could resolve the irises within the eyes, she could tell that yes they are these black things in the middle of the sclera, she could not tell what the significance of that was.

Natasha Mitchell: Right, so if the head was pointed one way but the eyes the other, she couldn't really tell which way they were pointing.

Pawan Sinha: That's right. So that was that one, and the other was visual imagery. If you ask her to imagine a picture she had a really hard time doing that.

Natasha Mitchell: The really interesting thing about this case and others that you've been working with is that for someone who's been blind for an extended period of time and then regained their sight and seem to pick up the skills of vision, where do these visual skills come from? Are they tapping into an innate visual capacity that we're all born with or is it a learned process?

Pawan Sinha: My hunch would be that it's mostly learned. There are some aspects of vision that one could call innate...say, the sensitivities of the very early visual neurons. But beyond that, making sense of the visual image, attaching meaning to these white blobs or coloured blobs that you're seeing out it the world, that, I'm almost certain, is learned.

Natasha Mitchell: Pawan, have we tended to underestimate the plasticity of the brain—sort of thinking of it as a rather stationary organ with little perhaps spurts of plasticity?

Pawan Sinha: I think so. I think traditionally we have believed that a lot of the brain is fairly fixed in its ways, and certainly the dogma in neuroscience has been that after the initial few years of life, the brain is pretty set in its ways; no amount of sensory intervention would get it to change its organisation, but new studies are suggesting that that view might need to be changed.

Natasha Mitchell: It's long been believed that there's a really critical period in the first few months of life for vision and our visual capacity to develop in the brain, which really...the prognosis then for people born blind hasn't been very good, has it? On what basis was this belief founded?

Pawan Sinha: The human data on this question are fairly sparse. When you do studies of depriving animals, like young soon as the kitten is born, you put the kitten in a darkened chamber for the first few months of its life. What one finds is that that period of deprivation permanently impairs the kitten on visual tasks for the rest of its life.

Natasha Mitchell: And that was Nobel Prize-winning work, wasn't it?

Pawan Sinha: Indeed. Extrapolating from these kinds of results to the human, what we're finding is that that strict interpretation of the critical periods idea is perhaps too strict.

Natasha Mitchell: It gives a lot of hope, doesn't it, for a huge percentage of the world's population. I mean, 25,000 children approximately are born blind in India each year.

Pawan Sinha: In fact the doctors that we're working with in India tell me that until they started participating in Project Prakash and began seeing evidence of these visual skills, they would not operate on children older than four or five years because they thought that it would be a pointless exercise.

Natasha Mitchell: The tragedy of this story is that your subject, SRD, she actually died on the way to taking her daughter to a vision clinic recently, didn't she.

Pawan Sinha: Just on a purely human level, one of the things that really struck me about SRD when I met her was just how many hardships she had overcome; born into a very poor family, she was blind, she was taking care of her daughter and her husband, her husband was not making any money at all. I admired the resilience of the human spirit. And then to hear that last year she met this accident, it really upset me a lot, a great tragedy.

Natasha Mitchell: She was pulled under a bus. It certainly transforms your relationship to your science, I would imagine.

MIT neuroscientist, Associate Professor Pawan Sinha, founder of Project Prakash.

Let's climb, then, back into the experience of what it's like it to lose your sight. Nearly 60 years on, psychologist Zoltan Torey, author of The Crucible of Consciousness, remembers it well.

Zoltan Torey: You feel like you're being buried alive, it's ghastly stuff.

Natasha Mitchell: Deeply claustrophobic.

Zoltan Torey: Deeply claustrophobic, yes, and you instinctively try to fight it. When you have sight, the visual world pours into your retina, into your eyes and into your brain, whether you want it or not, you just keep your eyelids open, the world gets in to you.

Natasha Mitchell: Interestingly you've called that...the sight most of us possess as a 'passive immersion in light', it's almost a laziness, a lazy seeing.

Zoltan Torey: Yes, because what I have then acquired is active vision, the creative vision where you imagine the world around you and then move it around, do things with it. Artists do that, film-makers, writers, work out visual patterns, models, pictures in their own head, and then of course they put it out on canvas or whatever.

Natasha Mitchell: And yet, Zoltan, it's interesting, as your body healed from the shock and trauma of the acid attack, you were told to let go of the visual, weren't you.

Zoltan Torey: It is a very, very terrible idea, I could never accept it. It's like virtually voluntarily getting into your own grave and pulling the lid on top of yourself, it was unacceptable. So instead of that I tried to immediately visualise where I was, who the people were around me, and I created a virtual world. When I walked along the street there were virtual cars and virtual driveways and houses and people and faces and I began to populate it with meaningful context and stories, and human faces and voices began to come alive for me.

Natasha Mitchell: So your mind's eye has, in effect, become a richer internal experience...

Zoltan Torey: Oh yes, absolutely.

Natasha Mitchell: ...than you had when you were sighted.

Zoltan Torey: Exactly, because of course I didn't need to do this, but I have to do it and I am doing it continuously all the time.

Natasha Mitchell: Has the content of that visual world within evolved, or does it still draw on the visual triggers that you had before the accident as a young man, your visual sense of the landscape that you possessed then?

Zoltan Torey: It is still using the old material but of course in constantly new combinations. But what is new of course is just the way in which I am able to combine things in my brain without the interference of vision. Normally when people want to think they close their eyes because the flood of visual impressions that comes at you is a distraction. I have the privilege of not having to cope with that, of thinking without...I'm a sort of 'thinkaholic', if I might use this expression. This is the way I did my research work about psychology and the consciousness. Not being troubled with vision itself, it was possible for me to imagine complex internal systems, and so I have this marvellous opportunity to run an internal show like a movie director.

Natasha Mitchell: What is that subjective experience like? Because it sounds like a sort of ongoing hallucination of sorts.

Zoltan Torey: Yes, that is exactly what it is, but of course it is anchored to reality in know, my physical sense, my hearing and my touch and smell, taste, locks me into a reality which excludes the possibility that this would be just hallucination. My imagination merely allows me to play in it, live in it, to create in it, to feel in it, but the 'it' remains reality always.

Natasha Mitchell: Zoltan Torey, on ABC Radio National.

Dr Amir Amedi is instructor of neurology at Harvard Medical School, and a research fellow with the Centre for Non Invasive Brain Stimulation at the Beth Israel Deaconess Medical Centre. He and colleagues [notably his mentor and colleague Professor Alvaro Pascual-Leone who heads up the Non Invasive Brain Stumation Centre] have been working with blind people to see how their brains 'see'. And it seems the part of their brain that would usually be dedicated to sight—the visual cortex—becomes colonised by other opportunistic senses and capacities.

Amir Amedi: We used to think that about 30% or even more of the brain is dedicated to vision and to vision only, and then what we found is that even in adult people the brain is capable of changing so it can be activated by different modalities.

Natasha Mitchell: In one study you blindfolded 'seeing' people for up to five days, and you noticed that the visual centres of the brain, which is a large portion of the rear of our brains, actually became co-opted for other sensory skills, like touch or hearing, which is extraordinary, in just that short amount of time.

Amir Amedi: Exactly, and in another study which we performed both on sighted and blind people we used something that is called sensory substitution. It's a device that takes the images and translates the shape of the objects into sight, into vision, and then what we found out is that part of the visual cortex which is called the occipital temporal cortex which usually is activated by visual optical cognition but not by auditory optical cognition...

Natasha Mitchell: So, just to check, you actually took pictures of objects and turned them into a sort of equivalent sound?

Amir Amedi: Exactly. For example, in our case, it's a device...after about four weeks of training people start being able to recognise objects using this device, only by hearing them.

Natasha Mitchell: So the visual part of the brain is actually used to identify objects through sound.

Amir Amedi: Exactly. So it becomes really confusing. What is the brain doing? Is it doing vision, is it doing audition, is it doing touch? Maybe the way to look at is not asking to be a little bit chauvinist, you know, or this brain region is just doing this, it's just doing the vision, it's just doing touch, and if we will understand better the interaction between the senses we would gain a better understanding of how the brain functions and how we can maybe help in these cases of blindness.

Natasha Mitchell: And Dr Amedi and colleagues have found it's not just hearing that takes over the visual centres of the brains of blind people; when they read Braille through touch, the visual cortex is uniquely activated too. And it's also activated when they're remembering words and numbers, which you also don't see happening in the brains of sighted folk.

Amir Amedi: Actually their memory skills, their verbal memory skills are much higher than the average capacity of sighted people.

Natasha Mitchell: And verbal memory just means the memory we use when we remember words.

Amir Amedi: Words or even numbers. Their verbal memory capacity is much higher. What we found is that actually their left visual cortex is recruited and robustly activated when they are doing a verbal memory task which has nothing to do with vision.

Natasha Mitchell: Right, but what about the rest of us? Do we activate the same part of our brain when we're remembering words?

Amir Amedi: No, we are activating other brain regions such as the prefrontal cortex or the parietal cortex.

Natasha Mitchell: You've actually worked with a person who was totally blind for all their life but who could paint beautifully, three-dimensionally, objects that he'd never seen, with the perspective right and everything.

Amir Amedi: Yes, actually it's a very exciting opportunity that...his name is Esref Armagan and he's a blind Turkish painter, but he's able to basically represent to a sighted person a visual scene just by his touch and by drawing by touch. So he basically draws with one finger on a rubberised plastic board which he can feel the indentation of what he's drawing. He can understand concepts such as vantage point, so we would give him objects and ask him to paint it or draw it from the top and he would be able to do it. The second thing we were very interested in is what's going on in his brain and we imaged his brain while he was drawing objects. Indeed we found that his visual cortex is strongly recruited when he's drawing objects.

Natasha Mitchell: So he was drawing objects by touching them, or were the images also coming from nowhere?

Amir Amedi: Some of his painting is really amazing. For example, he draws someone playing under the ocean while fishes are wandering around, so some of his stuff is pretty abstract. But he's also being able...for example, when he visited the Metropolitan Museum he would touch a sphinx and then draw it.

Natasha Mitchell: The team Amir Amedi is with uses a technology called transcranial magnetic stimulation, or TMS. With it they can temporarily block the activity of different parts of the brain, just for a moment. Blocking the activity of the visual cortex in blind people, it turns out, dramatically compromises their performance on verbal memory tasks. Not the case for sighted people.

So the visual cortex is being co-opted in important ways in the minds of the blind, without them ever having a visual experience.

Zoltan Torey: To switch just to hearing and touch as a source of information would be a terribly impoverishing experience. If to be blind means that you can't see, then of course I'm not blind because I'm seeing all the time and generating vision all the time. Really I feel in exactly the same way in which you would feel if you would now close your eyes...

Natasha Mitchell: Which I've just done actually...

Zoltan Torey: ...for ten seconds. During this time you would still feel yourself unaltered, your identity, your looks, your appearance, with your memories, with your capabilities. You would not feel blind. No, I don't feel blind. To me sometimes it comes as a surprise. Sometimes I say to myself, goodness me, I can't see a bloody thing!

Natasha Mitchell: I'm interested to know how you use your other senses and what role they play in sight. As you mention, the Royal Blind Society told you, way back when, you should let go of vision and focus on touch and smell as your means of rebuilding your mental representation of the world. So how do touch and smell and hearing fit into your visual experience?

Zoltan Torey: Well, in an auxiliary sense only. My concentration and my focus, my sense of reality is so embedded in the visual cortex that, for example, when I do something—pour a cup of coffee or I hit a nail into a piece of wood—I see the thing, and if I would 'look away' I would fumble, I would not be able to pour that water into the cup or I would not be able to hit the nail on the head properly. The take-home message in all this is that the brain can accomplish a great many wonderful things if you stick to it and if you use it.

Natasha Mitchell: Professor Pawan Sinha, if I can come to you; if someone has been born blind, as with the subjects that you're working with in India and they regain their sight later in life, how do they regain their sight? Where does it start? Do they start by seeing a cow as a cow, or do they have to train their brain to see, as much as training their eyes to see again?

Pawan Sinha: Yes, it's very much a matter of training the brain. So on the first day when you remove the bandages the child really does not make sense of the world, they report that everything looks very bright, the colours are very vivid, but if you ask them to count the number of objects that you put on a table in front of them, they have a hard time even doing that. So it takes a while for them to begin to parse the world meaningfully.

Natasha Mitchell: If we're drawing on Professor Amedi and colleagues' work where it's obvious that the visual parts of the brain in blind people become co-opted by smell and touch and verbal memory and language, then in the population of young people that you're studying, I wonder if their visual parts of their brain, when they start seeing again, have to sort of unlearn their preference for touch and sound and smell.

Pawan Sinha: That is truly a fascinating question. In fact we will begin imaging these children beginning this summer, and that is precisely the question we are starting out with; would it be the case that after the onset of sight, vision will be able to reclaim the territory...

Natasha Mitchell: Have you got a hunch?

Pawan Sinha: Not yet. We have some preliminary data but they're so preliminary that....

Natasha Mitchell: wouldn't even dare to comment on them.
I could speculate that as they're learning vision their smell might actually become less skilled or their touch might become less sensitive.

Pawan Sinha: I won't really say anything much about the experimental data that we have but that does seem to be the case...very preliminarily though.

Natasha Mitchell: A final question for you both, I wonder what all this work and effort that you're directing towards understanding the brains of blind people says about the brains of people who see?

Amir Amedi: I think that the main take-home message is that our brain is much more dependent then we previous considered on the interaction between the different senses and there is a lot of plasticity that is possible and that the brain is capable of quite radical plasticity.

Natasha Mitchell: Professor Sinha?

Pawan Sinha: Yes, I would echo that. The key message is that the brain retains its youth or its ability to learn well into adulthood, so even those of us who are old, what we would think as being old, we can still expect to learn a great deal of new stuff, that the brain can compensate for, say, damage to one part of the brain—so it essentially becomes a very dynamic learning system rather than a static processor of information.

Natasha Mitchell: I find both of your work absolutely intriguing and good luck with the continuation of it. Professor Pawan Sinha at MIT and Dr Amir Amedi at Harvard Medial School, my thanks for joining me on the program this week.

Amir Amedi: Thank you.

Pawan Sinha: Thank you very much.

Natasha Mitchell: Pawan Sinha, Associate Professor of Vision and Computational Neuroscience at MIT.

And I'll link from our website to Project Prakash, his humanitarian and scientific effort to restore the sight of Indian children with prolonged congenital blindness. And if you think that wasn't enough strings to his bow, he's also an accomplished cartoonist and he and his students go down in the Guinness Book of Records too for publishing the world's tiniest book, a five by five millimetre New Testament!

And before him Dr Amir Amedi from Harvard Medical School and the Beth Israel Deaconess Medical Centre there in Boston.

[to Zoltan Torey]...Not everyone who loses their sight is able to reactivate their mind's eye in the way that you have. Have you spoken to people who are blind about that and about your own experience?

Zoltan Torey: Not really. I don't know what makes the difference. I think love of life to begin with, love the process of life and the opportunity and the privilege to be able to participate in it and to make sense of it, it's a wonderfully rich business...

Natasha Mitchell: ...Magical. Zoltan Torey, thank you so much for joining me on the program this week, I appreciate it very much.

Zoltan Torey: It's a pleasure.

Natasha Mitchell: Zoltan Torey, and you can read his memoir Out of Darkness published by Picador. His other book The Crucible of Consciousness is about to be republished by MIT Press.

And this whole idea that our brains are incredibly adaptable and plastic, even for adults, holds interesting possibilities for a bionic eye or a visual prosthetic, even a retinal chip to help restore the sight of people who are blind.

But would near enough be good enough?

That's the show next week.

Thanks this week to Anita Barraud, Kyla Brettle and to sound engineer Tim Symonds. I'm Natasha Mitchell.


Zoltan Torey
Author and psychologist who lost his sight completely in an industrial accident in 1951
Pawan Sinha
Associate Professor of Vision and Computational Neuroscience
Department of Brain and Cognitive Sciences
Massachusetts Institute of Technology, MIT
Amir Amedi
Instructor of Neurology
Center for Noninvasive Brain Stimulation (CNBS)
Beth Isreal Deaconess Medical Center and Harvard Medical School


Out of Darkness: A Memoir
Zoltan Torey
Picador /Pan Macmillan Australia, 2003
ISBN: 0 330 36421 9
The Crucible of Consciousness: A personal exploration of the conscious mind
Zoltan Torey
Oxford University Press, 1999 (MIT Press republishing the book in 2007)
ISBN: 0 19 550872 6
Vision Following Extended Congenital Blindness
Yuri Ostrovsky, Aaron Andalman, and Pawan Sinha
Psychological Science, Volume 17, Number 12, 2006
The Plastic Human Brain Cortex
Alvaro Pascual-Leone, Amir Amedi, Felipe Fregni, Lotfi B. Merabet
Annual Review of Neuroscience. 2005 28:377-401
Cortical plasticity associated with Braille learning
Roy Hamilton and Alvaro Pascual-Leone
Trends in Cognitive Sciences, Vol 2. No 5. May 1998
L.B Merabet, J.F Rizzo, A Amedi, D.C Somers, A Pascual-Leone.
J Physiol Paris. 2004 Jan-Jun 98(1-3) pages221-33
L B Merabet, J.F Rizzo, A Amedi, D.C Somers, A. Pascual-Leone
Nature Reviews Neuroscience 2005 Jan 6(1) pages 71-7
The Occipital Cortex in the Blind: Lessons About Plasticity and Vision
2005 American Psychological Society Volume 14-Number 6
Negative BOLD Differentiates Visual Imagery and Perception
Amir Amedi, Rafael Malach, and Alvaro Pascual-Leone
Neuron, Vol. 48, 859-872, December 8, 2005
Amir Amedi, Noa Raz, Pazit Pianka, Rafael Malach, and Ehud Zohary.
Nature Neuroscience, Volume 6, Number 7, July 2003
Look and Learn (News feature about Pawan Sinha and Project Prakash's work)
Nature, Vol 441, 18 May 2006

Further Information

Project Prakash
Founded by Associate Professor Pawan Sinha. Their goal is to help curably blind children, especially in India, access the surgery they need to see, and study how their progress in the effort to gain insights into how the brain learns to see.
Dr. Shroff's Charity Eye Hospital
Who work in partnership with MIT's Project Prakash
The Sinha Lab at MIT
Professor Sinha's team study how the brain recognizes objects, scenes and sequences.
Various publications on brain plasticity and blindness
by the Laboratory for Magnetic Brain Stimulation at Beth Israel Deaconess Medical Center, directed by Alvaro Pascual-Leone. The team are using brain stimulation techniques to study the brains of blind people.


Natasha Mitchell
Natasha Mitchell / Anita Barraud / Kyla Brettle