The study led by Pawan Sinha, professor of vision and computational neuroscience, department of brain and cognitive sciences, Massachusetts Institute of Technology (MIT), is part of 'Project Prakash' that works with Indian children who were born visually impaired. It has screened 40,000 children since 2005 and provided surgical treatment to 400 of them.
In a report published in Public Library of Science (PLoS) Biology on 17 December, the scientists say that the study has given them insights into how they developed visual skills after years of blindness.
"Our findings paint a picture of a brain that remains impressively adaptable well into life and that can reorganise itself quite rapidly to allow a newly sighted child to make use of the novel sensory information received from its eyes," the paper says.
According to the study, the onset of sight challenges the brain to link the visual information it receives with signals from other senses such as touch and hearing.
"Immediately after the onset of sight, the children could not recognise by sight an object they had felt with their hands, that is, there was no evidence of an innate link between vision and touch," the report says. "However, they became proficient in as little as a week, indicating that the brain is taken by surprise by the new inputs but learns in a short span of time to cope with them and link them with inputs from other senses."
A key finding is that the brain has sufficient plasticity to acquire significant visual function even late into childhood. "The result is important from both the basic scientific perspective and the applied clinical one," Sinha tells SciDev.Net.
Sinha says the the project provides a gateway to understanding how different visual abilities develop which, in turn, raises hopes for treating some of the currently untreatable forms of blindness.
Doraiswamy Balasubramanian, director of research at the LV Prasad Eye Institute, Hyderabad, says that the study is significant as it shows that the neural circuits in the brain of a blind person become activated when he gains sight.
"This suggests that even after 10-20 years of blindness, once sight is restored, the brain rewires part of its neural connections. This reverses the earlier wisdom that the brain is hardwired and cannot readjust itself," Balasubramanian said.
Link to report in PLoS Biology