When adults learn to read, the brain rewires itself

In illiterate Indian women taught to read, brain’s ancient and new regions change in 6 months and coordinate, study finds

Written by Harikrishnan Nair | New Delhi | Updated: June 12, 2017 1:27 am
Brain study, Brain Research, Brain, Science News, Indian Express, Indian Express News Falk Huettig of Max Planck Institute was the lead author of the brain study, published in Science Advances (llustration: C R Sasikumar)

On the outskirts of Lucknow, 21 illiterate adults, 20 of them women and all around 30 years of age, were part of a unique experiment to study how learning to read affects the brain. They were taught how to read and write Hindi over the course of six months, starting with the alphabet and moving on to words and then some grammar. Before and after the course, researchers mapped the brains of the participants with functional magnetic resonance imaging, a procedure that detects brain activity by measuring changes in blood oxygen levels. Their objective was to identify which areas of the brain showed greater activity as a consequence of learning to read.

What they found surprised them. While they had expected that there would be some development in the outer cortex region, they also found changes in areas located deeper and considered more ancient. The reason this is surprising is that human writing is a relatively young phenomenon but the changes took place in brain regions that are very old in evolutionary terms. These regions, in fact, are already core parts of mice and other mammalian brains, according to a report on the research in the Max Planck Institute of Psycholinguistics in the Netherlands.

Falk Huettig of Max Planck Institute was the lead author of the brain study, published in Science Advances. The team included Max Planck researchers as well as Indian scientists from the Centre of Bio-Medical Research (CBMR) in Lucknow, the University of Hyderabad and the University of Allahabad. The human brain is a product of evolution over many millennia. Over time, billions of neural pathways have been created, some even destroyed, to form the network humans use today. It is in that sense that scientists call some parts new and others ancient.

To recognise patterns, to distinguish between a rabbit and a viper, and to use a hill as a reference for direction, for example, are survival necessities that the brain mastered ages ago. Reading, however, is something the brain would have processed much more recently, considering that complete scripts came about only a few thousand years ago.

Visual information moves from the eye through the retinal nerve into the midbrain and then into the visual cortex at the back of the brain, where the signals are interpreted. In the thalamus, the part located above the brain stem, are a part that amplifies visual signals (superior colliculus) and another that filters this information (pulvinar).
The study saw these regions and the visual cortex coordinate to accomplish the complex task of reading, becoming more efficient at communicating with one another as one got more proficient in the language.

“It may seem simple to the trained mind but, to the uninitiated, reading means fine coordination and synchronisation of different parts of the brain — visual, auditory and even motor. It requires the brain to associate visual, language and auditory information,” said Prof R K Mishra, head of Centre for Neural and Cognitive Sciences, University of Hyderabad, and a co-author of the study.

“These systems support reading and therefore it’s possible to estimate why the brain became cognitively fit to acquire reading. What our study shows is adult neuroplasticity at work,” Prof Mishra told The Indian Express. What exactly happened inside the brain when the study participants learnt to read?

“There are two views on what happens in the brain,” Prof Mishra said. “There are the structural neural pathways which are created with much more synapses creating new avenues for information. Secondly, there are the functional pathways, which connect the diverse regions of the brain, which are not otherwise connected structurally, to respond to situations. Reading requires such coordination among language, attention and visual areas including motor areas.”

The study came about after a decade of research on the brain and literacy, Prof Mishra said. In an earlier study, Prof Mishra said, the researchers wrote about how eye movements of illiterate people were found to be a second slower than those of literate people. That may not seem like much, but consider being in a situation where making a split-second decision is of utmost importance.

At last count, one in four Indians was illiterate or low literate. Many adult literacy programmes are ongoing and Prof Mishra believes the study could help bridge the gap between targeted learning and scientific learning. “With more such imaging techniques, representative data can be created to help policy-making and help train people’s core systems to better literacy programmes,” Prof Mishra said. “Moreover, dyslexia, which was once considered a linguistic disorder, is now believed to be in the domain of visual-attention and thalamus has a huge role to play here.”

harikrishnan.nair@expressindia.com

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