Evidence that brain circuits can be ‘re-purposed’ was recently reported in a study published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).
Researchers found that Deaf people had the same auditory processing regions in their brains activated when they interpreted visual rhythms from a flashing light, as when normal hearing people listened to the rhythms.
Researchers used functional MRI scans to take brain scans of both Deaf and hearing subjects under various test conditions.
All subjects were asked to discriminate between different rhythms of flashing lights.
Hearing subjects were also asked to listen to, and discriminate between, different rhythms, which were played to them.
As anticipated, in the flashing light test the brain scans of the hearing subjects showed activity in the visual processing system. Scans taken during the audible version of the task showed that the auditory cortex was activated.
However, in the Deaf subjects, the brain scans showed that the auditory cortex was activated when looking at rhythmic patterns of flashing lights (as were parts of the visual processing system).
The Deaf subjects’ neural responses to the visual rhythmic stimuli closely matched the hearing subjects’ neural responses to the auditory stimuli, with both groups brains showing reactions in their auditory cortexes.
“These findings are important because though we know the brain is capable of reorganizing itself, we don’t know what principles govern this reorganization,” according to Ars Technica Science Correspondent, Roheeni Saxena.
“Here, the authors demonstrate that the exact same regions that allow hearing people to interpret auditory rhythms are used by deaf people to interpret visual rhythms. This suggests that the rewiring of the brain may directly map similar tasks to specific functional units in the brain. Though more research is needed, this study adds to our overall understanding of neural rewiring.”