A seven-year-old boy who lost the visual processing center of his brain at two weeks old has shocked doctors by having normal sight.
The unidentified Australian boy, known as BI, lost his visual cortex due to a rare metabolic disorder called medium-chain acyl-Co-A dehydrogenase deficiency.
Now a report has revealed that BI is the first person ever to have normal sight without a visual cortex as he is able to play soccer, see colors and identify faces and only suffers nearsightedness.
New tests showed that his brain rerouted itself to make up for sight, leading researchers to believe that newborn brains can recover and adapt much better than mature ones.
An MRI shows a normal brain (left) and the seven-year-old Austalian boy’s brain that has been missing the visual cortex (right) since he was two weeks old
The visual cortex is the part of the brain that receives and processes sensory nerve impulses from the eyes, ultimately giving you the ability to see.
People with damage to this area have cortical blindness.
A series of tests by Monash University in Melbourne, Australia, showed that BI scored perfectly when asked to name objects, colors and identify people’s facial reactions distinguishing between happy, fearful and neutral.
Researcher Iñaki-Carril Mundiñano at Monash University, said: ‘You wouldn’t think he is blind. He navigates his way around without any problems and plays soccer and video games.’
The results presented this week at the annual meeting of the Australasian Neuroscience Society in Sydney, found the only flaw in BI’s vision was nearsightedness.
He was unable to read the top letter on an eye chart when standing more than four feet away.
People with damaged visual cortices have previously been found to have a degree of unconscious visual awareness, known as blindsight.
Blindsight is the ability to respond to visual stimuli without consciously perceiving them, such as navigating through an obstacle course while blindfolded.
An MRI brain scan found that other areas of BI’s brain appeared to have assumed the role of sight.
Compared to other children his age, BI’s scan showed more neural fibres running through two areas of the back of the brain near the visual cortex.
Those areas are called the pulvinar and middle temporal area.
The pulvinar is involved in controlling sensory signals, while the middle temporal area helps detect motion.
Mundiñano suggests that these connections formed because he lost his visual cortex in the first two weeks of life when his brain was still highly malleable and adaptable.
He said: ‘Younger brains just tend to recover and adapt much better.’
Previous studies found that monkeys also retain many of their visual abilities if their primary visual cortex is damaged during infancy.
This preservation was associated with extra connections between the pulvinar and middle temporal area, similar to BI.
Though more studies must be done, research suggests that those connections may be what give a person unconscious vision to experience blindsight.