Researchers in Brazil have discovered, for the first time, how those born without the ability to see have their brains reorganize to compensate for their disability. Their findings were published in the journal Human Brain Mapping.
This study was conducted by researchers from the Center for Specialized Ophthalmology, Brazil (Cesp), the Federal University of Rio de Janeiro (UFRJ), and the D’Or Institute of Research and Education (IDOR).
Studies conducted a few decades ago revealed the intriguing finding that non-visual activities, such as reading in Braille, might stimulate the vision-processing area of the occipital cortex in persons born blind.
These findings added to the growing body of evidence for “brain plasticity,” or the brain’s capacity to adapt by rewiring neural connections in response to stressful situations. This might include a range of structural adjustments, such the formation of new neuronal pathways or the rearrangement of preexisting connections.
MRI was utilized to examine the human brain’s structural connectivity and to look for evidence of potential new neural connections. Ten people born blind were studied by comparing their brain images to those of ten people with normal eyesight.
After careful examination, researchers found alterations in the thalamus’s connecting structures. The thalamus is part of the diencephalon, the brain’s core area responsible for receiving, processing, and disseminating data from the human senses to the other brain regions.
Connections between the thalamus and the temporal cortex (the part of the brain responsible for hearing) were found to be stronger in those who were blind compared to those who had normal eyesight. This suggests that the visual cortex is not only engaged, but also invaded, by connections that fine-tune other senses, like as hearing and touch.
The research was the first to provide an alternate mapping of the thalamus’s connection with the occipital and temporal cortices in humans. These dynamic reorganizations have been hypothesized to be the mechanism by which congenitally blind persons experience stimulation of the visual cortex from non-visual inputs.