Professor Mriganka Sur, MIT, on how the brain processed information and how the frontier Science of Neuro Science may help us to understand Brain Disorders which will soon become the most significant illness to claim the attention of Medical Science

Professor Mriganka Sur

In a powerful and riveting talk, Professor Mriganka Sur spoke about what neuroscientists studied-- the human brain which was not only the ‘most complex machine’ but also the ‘first complex machine’.  He said that it helped us to ‘understand complexity’ and ‘what could be more complex than that’? He began by paying his respects to his former teacher Professor Balasubramanium who was Chair of the session, and by recalling with reverence, scientists like P.C. Chandra Roy, and Jagadish Chandra Bose, Meghnad Saha and Satyen Bose who had been key figures in creating the hallowed traditions of Science at Presidency College. He mentioned that Sir J.C. Bose was one of the first neuroscientists and a polymath as well.  Whereupon he added that it was not enough to just look back to the past. One needed such traditions in the future too.  He stated that he had been ‘mandated’ to speak about the possible confluence of the Sciences and the Arts, and he would make the human brain his starting point. 

He said that he would speak on the’ leading edge of Science’ and how that may be linked to the Humanities. The complex machine of the brain creates the mind and he would take the audience through that ‘frontier Science’ that helps us to understand the brain and the mind. He would also speak on the mind’s relationship to technology and what the limits of computation would be in the next generation.  He said that he would link ‘technology transformation’ with the ‘social transformation’ that accompanied it.

Professor Sur stated that about 100 billion brain cells actively create the mind and wondered how it was possible that the philosophical school stemming from Charvakya could posit that ‘mental activity’ was the product of a ‘physical mind’? He then went on to speak about the key concept of   ’cognition’. He said that cognition was an operational system which allowed the mind to ‘understand’, ‘perceive’, ‘communicate’ and ‘move in a goal oriented’ manner. 

He said that in the first section of his talk he would focus on brain disorders which have profound social implications.  Deepening our understanding of the brain will help us understand the mind which cannot be seen, and yet its interactions and interfaces with technology have profound social implications.  The second half of his talk will thus focus on how the mind deals with the latest innovations and developments in technology and what happens when the limits of technology in the form of the limits of computation are reached. So what happens when the ‘I phone’ created by Apple, becomes replaced by another model? Technological transformation and social transformation are linked. The question therefore arises, what kind of transformation does society ‘want’?

Beginning the subject of brain disorders, Professor Sur referred to the stroke that German New Objectivist painter Anton Räderscheidt suffered in 1967. Räderscheidt’s stroke was in the right parietal cortex.  After his stroke Räderscheidt painted four self- portraits. In the portrait Räderscheidt draws his right eye and right nose. It is not as though R could not see with his left eye. There was nothing wrong with his eye, but something ‘profoundly wrong’ with his ability to ‘pay attention’ to anything to the left of his vision. This is known as ‘left spatial neglect’. Cognition is ‘object based’ in that ‘internal models determine cognition’ and in Räderscheidt’s brain there are no pictures of the left of his vision. This tells us something central about cognition.   Thus if there is no mental construct in Raderscheidt’s mind that there is a left side, he won’t be able to paint it.  Thus although we cannot see the mind, it suffers physical consequences.  Thus although we cannot see the mind, it has physical consequences.

Then Professor Sur went on to say that the brain cells were known as neurons and there were a billion neurons in the brain. A neuron is the size of 10 microns which is 1/10^th the width of a hair. A neuron is like a pen drive, containing a great deal of information. Neurons keep in potassium ions and keep out sodium ions.  There are two ways in which neurons differ from other cells as in the liver or kidney. They generate action potential and they connect to each other at special junctions called synapses. The synapse is that junction where one neuron ends and another begins. Also, the electrical transmission between neurons gets transformed into chemical transmission. The brain is concerned with ‘encoding’ ‘transmitting’ and ‘decoding’ and this is the task that the neurons carry out.  

This used to be one very profound way of knowing the brain. However in the last 20 years technology has completely has completely transformed the way we can know the brain through the Magnetic Resonance Image, whereby by putting the brain within a magnetic field which processes the electrical information from the brain,  images of the brain are obtained. One can even image a single molecule in a synapse. One can image five orders of magnitude from 1/10^th to 1/1000^th the breadth of one human hair. There is an extraordinary range of technology through which these images may be obtained, like for instance, the multi-photon microscope.  

This extraordinary range of technology has unfolded that networks of brain areas underlie cognition. The picture of a car will provoke visual area, hearing the word will provoke the auditory area, and the language area has two parts: the concept area of speech and the motor area of speech. Professor Sur posited that meaning is derived through symbolic representation. Cognition is based on symbolic languages or symbolic representations. The Professor posited that he had taken the audience through a map of the brain, mind and cognition establishing that the brain had no access to the world but had only an internal model of it which was the mind and which in turn generated cognition.  

Professor Sur then went on to say that half the brain is devoted to vision. However what the brain receives are pixels which are transformed into elements of vision. Visual cognition arises from a hierarchical network of cognition. Our cognition is underlined by response of neurons to visual stimuli. Neurons often respond to edges of visual stimuli. This is called ‘orientation selectivity’ which is a key component of vision. We can image ‘orientation selectivity’. However this ‘orientation selectivity’ in neurons is not random. They are organized like ‘spokes on a wheel’ and this wheel is called a ‘pinwheel’. Nature has evolved this ‘pinwheel’ through evolution.

The nature of the world is refracted into our brain through electrical activity and this shapes the brain to process that world. The brain has no access to the outside world except through electrical activity. The electrical activity is often in the shape of spikes. One of the central questions in Neuroscience is this that the brain has no access to the external world, so how does it create this world? Electricity reverberates in the brain as spikes. Spikes contain molecular activity. Synaptic and electrical activity wire molecules in the brain. These molecules are regulated by different time frames within a synapse. Electrical activity changes synaptic expression which is also dependent on genes. Nature and nurture come together in the expression of electrical energy in synapses. Larger synapses remain stable but smaller synapses may keep changing. Professor Sur said that even while we were listening to him speak, some of our smaller synapses were changing. He said that he must have seen at least 10000 synapses in his life and no two synapses were the same.  

In most cases where human beings have congenital blindness or deafness, it is not as if the cortex is inactive. It is that the cortex has been taken over by other modalities. For instance, the visual area in the congenitally blind is activated by sound stimuli. Again for those who are deaf, visual inputs activate the auditory area of the cortex.

Recapitulating what he had already established, Professor Sur said that  brain cells were wired by molecules, molecules were made up of genes and genes and molecules were influenced by experience and input activity. The brain is receives information from the external world, but it does not simply mirror that world. As we know in Raderscheidt’s case, the eyes were bringing in information, but the brain was not using this information   because it has its own model.

Once this was understood again a new frontier in Neuroscience opened up, where scientists came to terms with ‘disturbed cognition’ in the brain.  Professor Sur had studied other patients who have right parietal syndrome and who have ‘left spatial neglect’. Therefore we conclude that the brain filters and focuses the world according to its own internal model.  This is a deep internal state which is very significant and profound for understanding both the brain and the mind. It leads us once again to the question that we have been confronting from the very beginning of this lecture-- How do we know what we do know.

Experiments performed on mice unfold cognition activities like ‘attention’; whether a mouse is paying attention or not. The mouse has cognitive powers, based on its 50 million neurons as opposed to 82—100 billion in a human being. Thus mice can be trained in a way that scientists may find out through experiment how its brain responds to stimuli, the quality of its attention to external objects, etc. For instance, if it does not get the ‘chocolate water’ which is its reward for performing a task correctly, how the brain of the mouse responds.  Then something like ‘imagination’ happens in the mouse’s brain regarding the time gap.

In the human brain there are high level neurons which carry the internal representation of Time and Space. Time may be determined by the brain ‘switching in’ and ‘switching off’ engagement with external reality. Therefore gap in attention, engagement, creates gap in knowledge. The mind’s activity can be mapped mathematically. There are states in the brain when it performs in an orderly manner and these states can be reduced to mathematical equations. All this leads to questions as to why and when the brain makes a mistake. Professor Sur said that this knowledge will definitely come to us when can image the entire brain as we will be able to as part of the U.S. Brain Drive.

WHO statistics prove that the greatest number of takers is by Cancer and Heart Disease. But as we control the two, Brain Disorders will become the most important and our greatest burden. One must understand that people with brain disorders are not responsible for them. It is not their fault. This understanding has social implications. Children with autism suffer and their parents suffer too. Parents start by asking questions like, ‘Why doesn’t my child want to talk to me?’

While summing up the Professor said that his talk had looked at 2 operational questions: a) how is the brain wired? B) How does brain wiring create cognition? The answer was that the brain depends on plasticity and specificity, creates circuits, which create dynamics, and which eventually lead to algorithms that structure the internal world. The question in this age of fast developing automation, may a machine be built this way and is there a ‘need’ for a machine to be built that way. Partially answering his own question Professor Sur pointed out that a computer needs 200 kilohertz of power and the human brain only 20 hertz. However we can go on cramming a machine with information that it may not be possible to do for a human brain. The question to raise here is how can Neuroscience help us here? It may be able to answer the question as to whether so much of automation is good for society. As much as society affects technology, technology also affects society. Professor Sur posited that one needed to think how greater and greater automation would impact health and also brain related diseases or disorders? He said that greater and greater automation were inevitable realities, so one needed to think deeply about the interrelationship of Science/Technology and Society.