When a completely illiterate person learns to read and write in adulthood, the human brain reorganises and transforms itself significantly, researchers say.
The findings, based on a study on women in rural India, showed that the learning process leads to a re-organisation that extends to deep brain structures in the thalamus and the brainstem.
Some regions of our visual system such as faces become engaged in translating letters into language, the researchers said.
"Until now it was assumed that these changes are limited to the outer layer of the brain, the cortex, which is known to adapt quickly to new challenges," said lead author Falk Huettig from the Max Planck Institute for Psycholinguistics.
The so-called colliculi superiores — a part of the brainstem — and the pulvinar — located in the thalamus — adapt the timing of their activity patterns to those of the visual cortex, the researchers observed, in the paper published in the journal Science Advances.
"These deep structures in the thalamus and brainstem help our visual cortex to filter important information from the flood of visual input even before we consciously perceive it," added Michael Skeide, scientific researcher at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS).
Interestingly, it seems that more the signal timings between the two brain regions are aligned, the better the reading capabilities.
The finding could also have implications for the treatment of dyslexia — a learning disorder characterised by difficulty in reading — which some researchers have blamed on a malfunctioning thalamus.
"Since we found out that only a few months of reading training can modify the thalamus fundamentally, we have to scrutinise this hypothesis," Skeide said.