Scientists have discovered how a 10-year-old girl born with half a brain is able to see normally through one eye. The youngster, from Germany, has both fields of vision in one eye and is the only known case of its kind in the world.
University of Glasgow researchers used Functional Magnetic Resonance Imaging (fMRI) to reveal how the girlâ€™s brain had rewired itself in order to process information from the right and left visual fields in spite of her not having a whole brain. The right hemisphere in the girlâ€™s brain failed to develop in the womb.
Normally, the left and right fields of vision are processed and mapped by opposite sides of the brain, but scans on the German girl showed that retinal nerve fibres that should go to the right hemisphere of the brain diverted to the left.
Further, the researchers found that within the visual cortex of the left hemisphere, which creates an internal map of the right field of vision, â€˜islandsâ€™ had been formed within it to specifically deal with, and map out, the left visual field in the absence of the right hemisphere.
Dr Lars Muckli of the Centre for Cognitive Neuroimaging in the Department of Psychology, who led the study, said: â€œThis study has revealed the surprising flexibility of the brain when it comes to self-organising mechanisms for forming visual maps.
â€œThe brain has amazing plasticity but we were quite astonished to see just how well the single hemisphere of the brain in this girl has adapted to compensate for the missing half.
“Despite lacking one hemisphere, the girl has normal psychological function and is perfectly capable of living a normal and fulfilling life. She is witty, charming and intelligent.”
I found this article in a blog entry by Josh Clark. Wild.