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Home / Health / When surgeons have removed one-sixth of the child's brain, the following happened

When surgeons have removed one-sixth of the child's brain, the following happened



Our developing brains are finding unique ways to rewire themselves as necessary, proposing a new case study of a nearly 11-year-old boy who is referred to simply as "UD" (his privacy is respected by never giving his true name reveals).

The surgery, when he was 6 years and 10 months old, eliminated the entire occipital lobe of the UD, the home of the brain's visual processing center and most of its temporal lobe, where both visual and auditory signals land and then sorted. However, UD's left hemisphere compensated for losses on the right side of his brain by taking over the roles of both hemispheres. As a result, his cognitive and visual functions are now intact.

"The case of UD [has] essentially showed us that a hemisphere is sufficient for normal visual functions," said Marlene Behrmann, senior author of the study and neuroscientist at the Department of Psychology and Center for Neuronal Foundations of Cognition by Carnegie Mellon.

"Last resort"

At the age of 4, when most children began to do a somersault to dress and name the many colors they saw, UD suffered its first epileptic seizure. Soon after, his seizures became frequent and serious.

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Over the next few years, his physicians made many attempts to control UD's seizures, mostly through medication, Behrmann said. Although some medications reduced his seizures, none stopped them.

"As a last resort, the decision was made to undergo a lobectomy," Behrmann said, explaining that this procedure required a surgical plan to eradicate the epilepsy center of gravity without affecting other regions of the brain.

"The surgery completely eliminates the seizures in about 60% to 70% of children [who undergo the operation] so it's really very effective," said Behrmann, who did not attend the surgery, which is performed at about 4% to 6% of all patients with uncontrollable epilepsy

In UD, a localized tumor in his right hemisphere was the cause of his epilepsy. The surgery, which took place at the age of 6 years and 9 months, removed the tumor along with most of two of its four lobes in the right hemisphere.

"We saw him almost a year later, when he was completely stable and no longer medicated and ready to attend," Behrmann said. Prior to the operation, he had gone through extensive behavioral and vision tests that were necessary "because they wanted to remove part of the visual system," she explained.

Over the next three years, Behrmann and her team investigated UD's position – surgical progress using high-tech scans to measure its brain activity at five different times.

Essentially, she and her colleagues observed how UD's brain had rewired after surgery.

What they saw was that the left hemisphere took over the functions normally performed by the missing regions of its brain. His left hemisphere then did its usual work of word recognition, but also assumed the role of recognizing faces, usually the responsibility of the right hemisphere.

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"As word recognition became apparent, we were able to find one in the same left hemisphere Identify position change between word recognition and face recognition, "says Behrmann. "They kind of pushed around a bit and then calmed down."

"And now [UD’s] facial and predictive skills are quite normal," she said, noting that both abilities had "somehow calmed down in adjacent and adjacent regions" of his brain in the left hemisphere.

Both word recognition and face recognition are considered "a complex pattern recognition problem," explained Behrmann. The reason is that words are visually similar to faces.

Even in typically developing children, the brain takes a long time to acquire these separate recognition skills, Behrman said, probably because "fine-grained must be the mechanism" to resemble similarly appearing words and words similar appearing faces.

She and her colleagues not only compared UD's skills with his colleagues, they also tested him with "the most difficult tests we could do," she said. "We really looked into whether or not there was a loss or a change in function, and we could not see any."

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Regions of the UD brain with other complex visual functions – object recognition and scene recognition – were present and normal when he was scanned by the study researchers at the age of 7 years 10 months. Like his colleagues, these advanced features became more sophisticated over time, proving that part of his brain remained in good shape, Behrmann said.

UD lost a skill due to surgery and will not return. Visual information appearing in UD's left field of vision now has "nowhere to go," explained Behrmann. Still absorbed by its functioning eyes, it is transmitted along the visual processing circuitry, but there is no brain region left to receive it.

To compensate, UD moves his eyes and head. We (unconsciously) do so for our own blind spots that occur where nerves that run from the eye to the brain block our vision. UD is probably unaware of this, and his appearance is not unusual, according to Behrmann.

Now, almost 11 years old, UD receives an eye therapy and sits on the left side of the classroom so he can see more of the school scene. His test results range from average to advanced.

Specialization

Mark Johnson, deputy director of the Center for Brain and Cognitive Development at Birkbeck College, University of London, said the UD case study was "very interesting."

"While some functions of the brain are known to work from birth, it is clear that many other specializations require extensive experience," wrote Johnson, who was not involved in the research, in an e-mail.

Since facelifting is such a critical skill, some scientists have argued that the areas of the cerebral cortex (mainly in the right hemisphere) responsible for recognizing faces are "upgraded" from birth for this purpose. Need to become. But the postoperative experience of UD – where words and faces vied for space in his brain – suggests the brain function model called "interactive specialization," originally proposed by Johnson in 2000. [19659009] According to Johnson's model, brain regions develop increasing specialization over time. Like sibling rivals within a family, brain regions interact with each other and compete with each other to acquire their role, which becomes sharper or narrower as they mature collectively.

Behrmann said that she and her colleagues "now have a very large scale study that rates many children," which, like UD, have undergone similar brain surgeries.

"Operations are getting much better, there are a lot of computerized maps to get the geography right, and there's a lot of work on the drug front," said Behrmann, who was funded by the National Institute for Health.

"We are in the midst of significant advances and advances in medicine and neuroscience," she said, all due to the development of new analytical and statistical techniques for handling large amounts of data alongside the expansion of new technologies [19659002] "There are so many unanswered questions, "said Behrmann.


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