Christian Long

Pawan Sinha: How Brains Learn to See

In TED Talks on May 1, 2010 at 11:20 pm

Reflection by DARCY S.

Original TED page w/ speaker bio, links, comments, etc:

Pawan Sinha:  How Brains Learn to See

Pawan Sinha does on a daily basis what I and hopefully many other humans should aspire to: utilizing his intellect and passion to better humanity and push the limits of our knowledge. The first thing the viewer notices is that Sinha holds a genuine love for his child, and this love he has drives him to give the benefit of vision his son has to every other child who is without it. This is the humanitarian aspect of Sinha’s mission. There is also another side to the mission, which is the scientific aspect. That is, simply, “to test the limits of visual plasticity” and to resolve the lingering mystery of what goes on in our minds in order to piece together visual information, or how the brain learns to see.

Sinha has engineered an exceptional program consisting of a duel-mission drive and focus. The project is called Project Prakash, and can potentially help thousands of vision-impaired children in India revitalize their eyes and experience the world in a way which would have been impossible if not properly treated. At the beginning of his talk, Sinha says that the chances of a blind or vision-impaired child receiving medical treatment are very slim, due to the larger focus of giving adults treatment. Some of the local treatments are completely spiritually driven and not rational at all. For example, a small village “doctor” treated an orphaned girl who had cataracts by taking blazing hot irons to her stomach to drive the demons out. This demonstrates there is a dire need for an accessible eye-care treatment centre for children, because eventually they grow into the adults that are currently being focused on and treated despite the essential time for treatment being earlier in life. Sinha’s mission is to change this, and so far that’s just what Project Prakash has done.

After displaying his concern for sightless children, Pawan Sinha brings up the theory of a “visual critical period,” tested by David Hubel and Torsten Wiesel. Their study of visual physiology, conducted in the sixties, won them the Nobel Prize in 1981, but didn’t convince Sinha. These tests run on kittens were applied to human children, and said that after four or five years of age, the brain loses the ability to learn to see. If this were true, Sinha’s entire humanitarian mission would be hopeless. However, Project Prakash has already seen results that defy Hubel and Weiesel’s work.

It starts with S.R.D., a woman that Dr. Sinha met at a city eye clinic in Ahmedabad in July 2003. Born with a heavy cataract, she was exposed to dangerous vision problems at birth and continued to live twelve years of her life with problematic cataracts. At this age, however, she had surgery in both of her eyes. The surgery failed in the right eye and left her with only vision in the left eye. Her experience with sight was troublesome; at the earliest stages post-surgery, her maneuverability was strictly limited considering she tripped over everything that was not in a previously determined position subject to her tactile sense, and she could distinguish varying levels of light (night and day). Later in life, S.R.D.’s family reports that she has aquired the ability of recognizing objects and people’s faces by learning them on her own. Her case alone disproves the work of Hubel and Wiesel, along with many other case studies Sinha has conducted.

After discovering it is possible, after many years, to learn how to see, the following question to ask is how it happens. The answer lies in many weeks of tests after a child’s surgery, and Project Prakash tries to conduct these tests for as long as possible.

I have recreated the first visual test that Sinha shows below.

The subject, who’s surgery was a little over a week prior to this test, is able to distinguish which is a circle and which is a square, assuming they have already learned what a circle and square look like. In the second test, the circle and square are overlapped.

This time, the subject was asked to locate where the shapes are. They pointed to three areas, including the space in which the two shapes overlap. Sinha explains this by stating that the world, to someone who is learning to see, is simply a quilt of objects. In a few months though, the subject sees two shapes in test two instead of three. The interest lies in the process that takes place in those months, and the key to distinguishing objects, Sinha says, is motion.

Next the subject is shown an image of a triangle with randomly placed fragmented lines on top of the triangle. When asked what they see, the subject replies that it is unclear to them. Then, the triangle is put into a circular motion and the subject can see that the object moving is a triangle. Then test number two is revisited. When asked, “how many things are these?” the subject answers, “three,” but after the square is put into motion, still overlapping the circle, the subject answers, “two, a circle and a square.” Granted that this result is seen through nearly every subject, it can be assumed that motion processing makes the foundation of visual inference and leads to recognition.

This idea has sparked Dr. Sinha’s newest experiment: Dylan. It involves a robot, and a camera attached to Sinha’s baby son. The goal is to teach a robot how to see, without using a human-programmer, without specifying what objects have x name and x meaning and x purpose. By attaching a camera to baby Darius’s head, the information recorded will serve as the information the robot is to learn from. Gradually, the acuity will go from approximately 20/800, that of a newborn baby’s, to 20/20, that of an adults. If the robot is able to learn to use sight as a literal sense, scientists around the world can mimic Sinha’s process to teach robots how to use other senses as well. All this entails is studying how a human learns to use senses and install a processor of this information.

Another way that Sinha implicates the newly discovered foundation of visual learning and processing is in the study of autism. Sinha asks if because it is believed that visual integration is associated with autism, “could the impairment of visual integration be the manifestation of something underneath the dynamic information processing deficiency in autism?” He then says that if this were true, we would come up with many different misunderstandings in the search for the cause autism and the autism phenotype. When comparing the efficiency of information dynamic used between an autistic child and a neurotypical child, it is seen that the autistic child has inefficient processing rate. Sinha ends that note by giving hopes for autism’s future.

Project Prakash has a heavy load on its plate. The goals of Sinha and many others who are working together are high and hopeful, and their humanitarian efforts will not go unnoticed. Along with the positive impact on humanity, the scientific world can be expecting numerous progressive steps in the field of brain physiology. In studying the processes of sensatory learning, it might one day enable scientists to give the gift of sound to an auditory-impaired person or even teach a robot to learn it’s senses in accordance on it’s own, in place of human programming. In any case, Sinha and his team are doing work that benefits children and adults and the scientific community in multiple ways.

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