Nandini Singh Chatterjee, a cognitive neuroscientist, has developed unique methods to study autism, dyslexia and language recognition in children.
The Wire is happy to support this project by Aashima Dogra and Nandita Jayaraj, who are travelling across India to meet some fantastic women scientists.
In the times of heavy propaganda and violent campaigns that describe the nation with the language of religious dogma, it is a relief to meet someone who chooses to examine ‘India’ rationally. ‘Rigorous scientific evidence’ is a buzz-term of Nandini Singh Chatterjee, neuroscientist stationed at the National Brain Research Center (NBRC), Manesar. To address the dizzying complexity of a multicultural India, Chatterjee studies our brains.
“There is so much neuroscience research to do in India. There is a treasure trove of stimuli to study the brain with. Imagine the possibilities of gustatory work – on different tastes, or with pashmina and silk – to understand how people learn to develop sensitivity in what is called the somatosensory cortex or the touch system. The language systems in which our children grow up… oh it’s just fabulous!’’ cried the neuroscientist, who has published several papers on reading in multilinguals, autism, dyslexia and the brain on Indian classical music.
Chatterjee was not always interested in brains, not even close.
In 1998, Chatterjee the physicist sat in a room at Ohio University facing a computer full of abstract numbers and equations. She was bogged down and in search for inspiration. “I was frustrated because I realised that all my work was in sitting in the computer. I was not able to take anything back to people,” she recalled during an interview at her office in the outskirts of Gurgaon. “I had an adviser who was an emeritus professor, so he was not around in the lab much. I was alone.”
As a postdoctoral fellow studying nonlinear systems (the branch of science and mathematics that tries to model systems with unpredictable changes), the self-described people’s person started to look for applications of her field. The timing couldn’t be better. At seminars, she witnessed an interdisciplinary merging of biology and nonlinear dynamics. “Scientists were beginning to use methods of nonlinear dynamics to look at biological systems that were not easy to explain mathematically. Biology itself was making an attempt to move away from descriptive to some quantitative work.”
So after work hours, Chatterjee looked for new opportunities as her baby daughter slept. “I used to spend the time looking at websites of labs with interdisciplinary research questions that would interest me. I sent out my CV to some of these.”
The learning curve
Chatterjee eventually broke away from pure physics in 2001 by accepting an offer from a lab in UC Berkeley, in the US. At Berkeley, she continued to think like a physicist, but this time within the context of modelling a biological system – bird brains. She was dealing with data composed of nonlinear signals which vary in time. “Nonlinear signals could be heartbeats, weather patterns… in this case, they were signals from the brain of the zebra finch in response to sounds from other birds of its kind.” The lab wanted Chatterjee to model the chaotic behaviour of zebra finch neurons.
“You would essentially model a linear behaviour with a straight line. But the neurons were clearly doing different things. It was not changing in a linear manner and it was not even clear what features of the input stimulus (bird song) it was responding to.” This was her first foray into biology.
“I loved the field of neuroscience. I got into mathematical representations of sound and analysing neuronal data.” At neuroscience conferences and workshops, Chatterjee recalls asking ‘stupid questions shamelessly’ – nevertheless, the excitement of it all kept her going.
At one such meeting – the annual meeting of Society for Neuroscience, which is one of the biggest meetings of brain experts – Chatterjee had an encounter with Indian neuroscientist Vijayalakshmi Ravindranath. Ravindranath, now at IISc, happened to be in the process of staffing the then newly formed NBRC and she prodded Chatterjee to chart her return to India to study human brains.
Chatterjee joined the NBRC in late 2002 and her first task was to set up a fMRI lab. “No one ever trains you on how to run a research lab. It’s like setting up a little company where you are given a pocket of money to deal with and then suddenly you are the boss in the lab. You have to manage finances, purchases and staffing. You have to find ways to get money to fund your research, support students’ research and you have to teach!” In addition, she said, there was also the matter of managing the personal work involved in setting up a new home. “There are a lot of things happening and just after a postdoctoral fellowship, these can overwhelm you.”
Getting started as a cognitive neuroscientist
As her lab was being set up, Chatterjee had already started to look for signatures of autism in babbles of young autistic children at NIMHANS, Bangalore. Her hunch was very early voice recordings should hint at underlying developmental problems in children. This was considered a very bold and audacious idea by her sceptics but Chatterjee was sure her rationale was sound.
Speech and language provide a lot of insight into how well the brain is functioning. It tells us if the brain is processing sound correctly. Essentially a means for social communications, language reflects on social developments and the intricate motor (related to movement) developments as different sounds are made.
With the voices she recorded on a laptop outside consulting rooms at NIMHANS, Chatterjee was able to show that there are indeed differences between the speech of non-autistic and autistic children. “Like is true of any disorder associated with the brain or the whole body in general, early identification makes a big difference,” she stressed. “These experiments also offered our first insight into understanding that children with autism like the predictable behaviour of machines. They love things that follow a pattern. What they don’t like is unpredictability.”
First adventure in imaging the brain
Meanwhile, Chatterjee’s fMRI lab was finally ready. To supplement her training in computational neuroscience and good scientific enquiry, she had been sitting in for neuroanatomy and systems neuroscience classes along with her students at NBRC.
The first experiment Chatterjee did on brain imaging was the replication of an experiment on how people read. It used the parameters as an existing study – only Hindi words were read instead of English words. Collecting the data from the MRI scanner was only the first part – then came the post processing. She ran me through what this entails: “All the brain images need to be aligned, the signal has to be measured, followed by identifying the regions of the brain that are active versus inactive, imposing them back on the brain scan and making sure the whole thing makes sense.”
“We managed to put out our first paper but it came back with terrible reviews,” she admitted. “The first journal immediately rejected it. But the reviewers were kind enough to respond with six pages of comments that I learnt a lot from.” The team addressed all the comments and Chatterjee’s first paper on reading in the Devnagiri script from India was published in the journal Reading and Writing. “It was the first paper of fMRI of its kind from India. There was a lot of excitement in the lab.”
That was just the beginning. Chatterjee and her team have done a lot more research on reading since then, including pinning down active brain networks in Indian biliterates (those able to read and write in two languages).
Making a tool for screening dyslexia
The subject of biliteracy and her earlier work with children brought Chatterjee face-to-face with dyslexia – the condition of difficulty in reading. In her research, she realised that no standardised systems existed in India to screen and assess for dyslexia. She took up the challenge and in 2005, Dyslexia Assessment for Languages of India or DALI was launched for use by teachers and psychologists.
“We have already built tools for screening in Hindi, Marathi, Kannada and English. These need to be extended to include other learning disabilities such as dyscalculia (difficulty with learning math), dysgraphia (difficulty in writing) and dyspraxia (difficulty in coordination and movement),” said Chatterjee, with a cautionary note. “It is important that teachers who are using DALI are familiar with the child for at least three to four months before they screen them. The idea is not to label the child but instead to identify if there might be areas of deficit that needs to be worked on.”
DALI makes India the only country in the world to have a native language assessment for dyslexia and Chatterjee is very aware of how crucial this is. She emphasised that learning to read is biological and a child with dyslexia cannot be dyslexic in one language and not dyslexic in another. Recognising her work, UNESCO has asked Chatterjee to come up with a universal screening tool which teachers across the world can use.
Disapproval of the obsession with English
Reading has become a pet subject of Chatterjee’s and she believes that in India the introduction to language literacy needs urgent repair. “The basis of learning to read is decoding symbols. We learn to map sound to letter, not letter to sound because we first learn how to speak. Words that are spoken are actually composed of different sounds that have come together. These different sounds are mapped to symbols,” she explained.
“Now if you step back a moment and think about this, the sound to letter mapping of Indian languages is fabulous – it is one of the reasons that these languages are phonetic.”
“English is really bad at that,” Chatterjee lamented. “COUGH is cough and BOUGH is bough… when a child learns this and thinks COW is written like COUGH you can understand why he/she did that because that’s how he/she learnt to decode. Yet, we push our children to first learn how to read English. They come to school with Gujarati, Bengali, Kannada in their brains and then we ask them to read English!”
“The child should be first applying this process of mapping sounds (reading) in the language he/she speaks. Then we can transfer the skill of reading to a second language. If for some crazy reason you are insistent that the child has to learn it first in English then first teach the child to speak English then teach him/her to read English. That’s my primary point,” she said exasperatedly.
“We absolutely have post-colonial baggage and we need to get rid of it. Your child doesn’t have to read Harry Potter at age five!’’
Further work on autism and music
Chatterjee’s later work on autism shows that kids with autism are sensitive to pitch changes. They took fMRI data from 25 autistic children and showed the difference in the brain wiring when words were sung to them. As they listened to the word ‘apple’ being sung, they observed that networks in the autistic brain were not any different from regular kids. But when the words were simply spoken, brain networks were extremely atypical with little engagement of the left hemisphere of the brain (where a lot of spoken language is processed) in autistic children.
“In the left hemisphere, somehow the networks in the brain were operating differently depending on the stimulus being used. Then we went on to use this information to follow up with another study where we designed an intervention where the special educator working with the child would sing ‘look at me’.”
They found that the child was more engaged, made more eye contact and his expressive skills also improved. Some of her students are now working with Srishti School of Design in Bangalore to create an app to help autistic children based on these results.
Chatterjee recently gave a TEDx talk explaining this phenomenon.