A 10 year old girl from Germany is the subject of a great deal of medical scrutiny of late. She has occasional spasms, and can only see in one eye. Other than that she seemed perfectly normal, until fMRI was used to image her brain.

She only has half a brain, one single side, the right. The right cerebral hemisphere is completely missing. The left, not only fully intact, but wired with an extra density of connections to compensate for the lost computational power. The girl herself, is normal in her intelligence and in her interactions with others.

More remarkable still, both fields of vision have been wired into the right eye. 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.

University of Glasgow researchers used fMRI to reveal how the girl'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.

Further, the researchers found that within the visual cortex of the left hemisphere, which creates an internal map of the right field of vision, 'islands' 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: "This study has revealed the surprising flexibility of the brain when it comes to self-organising mechanisms for forming visual maps.

"The 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."

The implications for prosthetics, BMI and VR are of course profound. Once that degree of brain plasticity is fully understood, it stands as incredible proof that the brain can readapt under the right circumstances, to any brain or body configuration as though it had always been that way.

We now know that it can happen, and the girl is living a normal life with it. All that remains is to figure out how her brain could have adapted so completely, and then replicate it in older brains. Not such a Herculean task once you know for certain that it is possible.

References

A Tale of Brain's Incredible Ability to Rewire Itself

Scientists reveal secret of girl with ?all seeing eye?