After losing chunk of brain, boy recovers visual system

Henrietta Strickland
August 3, 2018

Our developing brains find unique ways to rewire themselves as necessary, suggests a new case study of a almost 11-year old boy referred to only as "UD" (his privacy is respected by never revealing his true name).

The complete occipital lobe if UD-that comprises the visual processing center of the brain-and the majority of his temporal lobe-that obtains both auditory and visual signals-were detached, leaving only 2 of the 4 lobes untouched in his right hemisphere.

A new study provides the first evidence of how the human brain recovers the ability to function after losing parts of the visual system. UD likely is unaware of doing this and his appearance is not unusual, according to Behrmann. The life-threatening disorder cured by paying a small price. It is also found that some drugs reduced his seizures, but they can't stop them permanently. Behrmann described that this procedure needs a surgical plan that may help in removing the focal point of epilepsy which did not affect the other regions of the USA brain.

Behrmann said, "The surgery eliminates, completely, the seizures in roughly 60% to 70 percent of the children [who undergo the operation], so it is really highly effective". Behrmann is not involved in the study.

The primary cause of epilepsy is a localized tumor in the right hemisphere of UD. The surgery took place when he was six years and nine months old in which the tumor along with the most of two of his four lobes situated within the right hemisphere was removed.

"We saw him nearly a year later, when he was fully stable and no longer on medication and ready to participate", said Behrmann. Prior to the surgery, he had undergone extensive behavioral and visual testing, which was necessary "because they were going to remove part of the visual system", she explained.

After the surgery, she and her colleagues also studied that how the brain of UD rewired itself. Behrmann continues, "They kind of like pushed each other around a little bit and then settled down".

Behrmann said, "And now [UD's] face and word recognition skills are entirely normal".

Once that section of Tanner's brain was surgically removed, there was a risk that he would have trouble recognizing the faces of those around him, including his own parents, said Behrmann, a psychology professor at Carnegie Mellon.

At this point, the researchers don't fully understand how U.D.'s remaining brain is able to take on these new tasks without compromising other aspects of his cognitive processing, but the flexibility he's shown may be something to do with his age. We all (unconsciously) do to this cover for our own blind spots that occur where nerves, which run from the eye to the brain, block our sight. Although the process left UD incapable to witness the left side, the researchers discovered that the left hemisphere of his brain in time balanced for visual tasks such as identifying objects and faces.

"Moreover, by tracking the changes that occurred in the brain as UD developed, we were able to show which parts of the brain remained stable and which were reorganized over time", she says, offering insight into how the brain can remap visual function in the cortex. Both before and after his surgery, he had an above-average IQ, and his language and visual perception skills are age-appropriate. There is nothing wrong with his eyes, but without his right occipital lobe, he is unable to process the images that his eyes receive from the left side of the visual field.

He is now 11, and the only major differences between him and his peers is that he goes to vision therapy during the school day and sits on the left side of the class room so that the blank part of his vision - corresponding to his left eye - is directed to the edges of the room and he see more of his surroundings better. His reading proficiency is unchanged as well, still at above average. "The left hemisphere carries the function of recognizing words". Johnson said that the investigation is fascinating.

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