I am fascinated by neuroplasticity: the brain’s remarkable ability to adapt after it suffers from illness or injury. Recently, I came across two stories of women whose ability to function had not been severely affected by the absence of chunks of their brain.
Both stories are documented in the scientific literature. The third involves a woman with whom I am extremely close.
The Case of the Missing Cerebellum
When a 24-year-old woman in the Shandong Province of China was admitted to the hospital complaining of nausea and dizziness, she reported that she’d had difficulty walking steadily for much of her life. Her mother observed that she hadn’t begun walking until she was 7, and she didn’t speak clearly enough to be understood til a year earlier.
It’s a wonder this woman could walk at all. A CT scan revealed that the place in her brain where the cerebellum should have been held no tissue—none. Only the cerebrospinal fluid that protects the brain from disease and shock was evident.
The cerebellum—sometimes referred to as “little brain,” translated from the Latin—is a small area beneath the brain’s left and right hemispheres. It accounts for about ten percent of the brain’s volume. However, it’s a dynamo structure, accordion-pleated in a way that if the tissue were ironed out, it would be more than three feet long and four inches wide.
Within the cerebellum’s dense folds nestle fifty percent of the brain’s neurons. That woman was missing a hell of a lot of neurons.
According to New Scientist, which carried this story, “the woman joins an elite club of just nine people who are known to have lived without their entire cerebellum.”
We depend upon the cerebellum for balance and control of our voluntary movements, such as reaching out to grab a banana, as well as for speech. In view of her problems walking and enunciating, you may question my saying this young woman lived well.
But other people with cerebellum problems have been found to be severely mentally impaired or epileptic, and some have died due to fatal buildups of fluid in the brain. This woman had “only mild to moderate motor deficiency, and mild speech problems such as slightly slurred pronunciation.”
In conjecturing how her brain adapted to missing its entire little brain, her doctors suggested that the cerebral cortex may have jumped in and taken on extra work.
Scientists are continually studying the cerebellum, which apparently has existed among vertebrates for so long that Tom Stafford, writing for the BBC, observed: “the sharks that swam when dinosaurs walked the Earth had cerebellums.”
“I Have an Interesting Brain”
That’s how a woman identified only as EG described herself in 2016 to two MIT scientists she contacted after reading that they were studying the way the brain reacts to music.
Her brain, she wrote, is missing its left temporal lobe. As that area is believed to be essential for language processing, you can already see that this reading/comprehending/writing woman is defying some mammoth odds.
Though the scientists she emailed realized she was study-worthy, that wasn’t their area of interest. They referred her to a cognitive neuroscientist at MIT, Evelina Fedorenko, who studies languages.
According to an article published in Wired last year, “It was the beginning of a fruitful relationship.”
Fedorenko and her team published their first scientific paper about EG’s brain in Neuropsychologia, and they expect to publish additional studies.
EG, from the state of Connecticut, is now in her mid-fifties. How hindered has she been by the absence of her temporal lobe? Not enough to prevent her from obtaining a graduate degree, learning to speak Russian so fluently that she’s had dreams in this second language, and doing well in her chosen career.
She learned how interesting her brain is when she had a scan for some unspecified reason in George Washington University Hospital in 1987. The physicians theorized that she’d had a stroke when she was a baby. Like the woman missing her cerebellum, the scan showed only cerebrospinal fluid where the temporal lobe should have been.
The knowledge, she said, “creeped me out,” and for more than ten years, she told only her parents and two very close friends.
Her experiences with physicians during this period had been somewhat “interesting” as well. They told her that her brain “made no sense.” One doctor, she recalled, said she should be having seizures (she wasn’t). He also said she should not have a large vocabulary—and “he was annoyed that I did.” When the MIT team tested her vocabulary, she scored in the 98th percentile.
It’s surprising that after all EG’s frustrating experiences with physicians, which she said “pissed me off,” she sought out the MIT researchers. It’s not surprising, though, that Fedorenko and her team approached EG differently because what evolved was clearly a collaboration between researchers and subject.
EG was pleased that Fedorenko “didn’t have any preconceived notions of what I should or shouldn’t be able to do.” Fedorenko was delighted to have a willing subject to further her team’s studies of the various brain regions’ involvement in learning and understanding language.
A great deal is unknown about the functioning of various parts of the brain and how they work together—how the “system” develops. In terms of language development, Fedorenko pointed out that gaining greater understanding would require scanning the brains of children ages 1 to 3, when such development begins and progresses. But such technology wasn’t available.
EG was, therefore, a dream come true. She offered a “cool window” to learn how the brain tissue that she did have divvied up the tasks, enabling her cognitive functioning to be so high. That window showed her language facilities had simply shifted to her brain’s right hemisphere.
This finding validated the success of a surgical approach to help some children with severe epilepsy. Fedorenko observed that those who undergo a “hemispherectomy”—removal of the half of the brain where the seizures arose—have normal cognition.
“…That suggests there’s a lot of bits in our typical brains that are redundant…which is—engineering-wise—a pretty good way to build the system.”
Tom Stafford provided more details about that engineering, describing the work of Gerald Edelman, a Nobel Prize-winning neuroscientist. Edelman found that particular physical aspects are undergirded by multiple genes. “He called the ability of various different structures to support a single function ‘degeneracy.’”
I’m not sure why he chose that term.
“And so it is with the brain. The important functions are not farmed out to single distinct brain regions, but instead supported by multiple regions, often in similar but slightly different ways. If one structure breaks down, the others can pick up the slack.”
“…Not Worth Mentioning…
The third woman, ATB, with whom I’m close, said that as far as she knows, the first time her cerebellar anomaly was noticed on a brain scan about ten years ago, doctors apparently thought it was so “unremarkable, in medical terms,” that they failed to mention it to her. In fact, they didn’t seem to link it to the symptoms that had led her to call for emergency assistance.
As she’d left work early one evening, she said her legs became extremely wobbly and the world was spinning. By the time she reached her car, she thought she was about to faint. She called for help.
The ambulance took her to a major hospital, where she had a brain scan, blood work, and multiple other tests. After an overnight stay, she was released, told they could find nothing wrong, and advised to visit her primary care doctor.
That physician attributed the incident to a “perfect storm caused by a virus and a migraine headache.” ATB had been experiencing migraines since she was a young woman. Her doctor’s assessment seemed reasonable.
Fast forward to 2016. She was exercising in her gym on a seated elliptical machine, and she recalls engaging in a conversation with a woman who was equally “exercised” about the forthcoming Presidential election.
After pedaling longer and faster than usual, ATB left the gym feeling dizzy, with severe pain at the base of her skull. When the pain persisted for a week, she visited a neurologist, who ordered a brain MRI.
That MRI read, in part:
“The superior lobe of the right cerebellar hemisphere is hypoplastic/absent. This may be the sequela of a previous injury or a congenital/developmental variant…No acute intracranial process.”
The neurologist conjectured the pain was due to a persistent migraine brought on by the exercise. She felt physical therapy of ATB’s neck might be helpful, but referred ATB to a neurosurgeon to make sure such therapy would be safe.
ATB, learning for the first time that she was missing a piece of her brain, was eager to hear what the neurosurgeon would say.
She recalled that this patient and kindly man assured ATB that if the brain part was lacking due to an injury, she would have been stumbling around. He felt certain it was congenital, and the brain’s amazing adaptability had enabled her to lead a life so normal and active that learning about her brain anomaly had been a shock.
As Tom Stafford observed, though the cerebellum is best known to control movements, “other areas of the brain such as the basal ganglia and the motor cortex are also intimately involved in moving our bodies.”
ATB, knowing that people are living well with far worse brain conditions, has no compunctions about sharing her story.
It happens to be my story. C’est moi! ATB is Annie The Blogger.
I’m comfortable knowing that my “little brain” is littler-than-normal. I’m also eager to learn more about folks like me who are living well despite missing parts of their brains in order to further the understanding of brain functioning.
Just recently, neuroscientists learned that the cerebellum is central to remembering emotional experiences—both positive and negative—and that there’s greater communication between the cerebellum and the cerebrum than was previously known.
Studies to understand how the brain works are at a major threshold. The National Institutes of Health is providing grants for a BRAIN Initiative (Brain Research Through Advancing Innovative Neurotechnologies), backed by $500 million over five years, to explore the entire human brain—how it’s affected by diseases, “the breadth of human development and aging,” cell function to aid in developing treatments, and much more.
I’m grateful that I’m fairly well-coordinated, speak comprehensibly most of the time, and have no trouble touching my finger to my nose or my heel to my knee—common neurological tests for cerebellar disorders.
Nevertheless, the parts of my brain that aren’t missing would like to know what I may be missing because of my missing superior cerebellum lobe. I’d welcome the opportunity to participate in one of the BRAIN Initiative studies. However, I’m quite sure researchers would not be interested in a brain that clinicians who have documented its missing piece have deemed “unremarkable.”