Helen Santoro
I barreled into the
world — a precipitous birth, the doctors called it — at a New York City
hospital in the dead of night.
In my first few hours
of life, after six bouts of halted breathing, the doctors rushed me to the
neonatal intensive care unit. A medical intern stuck his pinkie into my mouth
to test the newborn reflex to suck. I didn’t suck hard enough. So they rolled
my pink, 7-pound-11-ounce body into a brain scanner.
Lo and behold, there
was a huge hole on the left side, just above my ear. I was missing the left
temporal lobe, a region of the brain involved in a wide variety of behaviors,
from memory to the recognition of emotions, and considered especially crucial
for language.-
My mother, exhausted
from the labor, remembers waking up after sunrise to a neurologist,
pediatrician and midwife standing at the foot of her bed. They explained that
my brain had bled in her uterus, a condition called a perinatal stroke.
They told her I would
never speak and would need to be institutionalized. The neurologist brought her
arms up to her chest and contorted her wrists to illustrate the physical
disability I would be likely to develop.
In those early days of
my life, my parents wrung their hands wondering what my life, and theirs, would
look like. Eager to find answers, they enrolled me in a research project at New
York University tracking the developmental effects of perinatal strokes.
But month after month,
I surprised the experts, meeting all of the typical milestones of children my
age. I enrolled in regular schools, excelled in sports and academics. The
language skills the doctors were most worried about at my birth — speaking,
reading and writing — turned out to be my professional passions.
My case is highly
unusual but not unique. Scientists estimate that thousands of people are, like
me, living normal lives despite missing large chunks of our brains. Our myriad
networks of neurons have managed to rewire themselves over time. But how?
‘The Worst
Participant’
My childhood memories
are filled with researchers following me around with pens and clipboards. My
brain was scanned several times a year, and I was tasked with various puzzles,
word searches and picture-recognition tests. At the end of each day of testing,
the researchers would give me a sticker, which I would keep in a tin container
next to my bed.
When I was around 9
years old, researchers wanted to see how my brain would act when I was
exhausted. I would sometimes stay up all night with my mom, eating Chinese food
and watching Katharine Hepburn and Spencer Tracy movies. The next day I would
stumble into the clinic half-awake, and scientists would stick electrodes on my
scalp. As long wires fell from my head like Medusa’s snakes, I was finally
allowed to fall asleep, blissfully unaware that the researchers were searching
for abnormalities in my brain waves.
Over the years, the
scientists realized that I wasn’t like the other children in the study: I
didn’t have any deficits to track over time. When I was around 15, my dad and I
met in the cluttered Manhattan office of Dr. Ruth Nass, the pediatric
neurologist leading the research. She questioned if I had actually had a
perinatal stroke. In any case, she said frankly that my brain was so different
from the others’ that I could no longer be in the study.
I didn’t mind. I had
other things going on in my life, like the beginning of high school,
cross-country practice and crushes. But I had also learned enough about
neuroscience to become consumed by the topic. When I was 17 and entering my
senior year in high school, I wrote to Nass and asked if I could do an
internship in her lab. She readily agreed.
One day in the lab, I
asked if she could show me my study files. We walked into a room filled with
stacks of plastic bins, each one brimming with folders and loose papers. She
grabbed a folder and read it quietly. Then, peering over a piece of paper, she
said, “You were the worst participant because you were perfectly fine! You
threw off all of my data.”
Nass, who passed away
in 2019, and her colleagues would go on to publish many studies on perinatal
strokes. In a 2012 paper, for example, they found that babies suffering these
strokes had a higher risk of attention and behavioral problems compared with
the general pediatric population. Many of these children — recruited from 1983
to 2006 from Southern California and New York City — suffered from seizures and
muscle weakness on one side of their bodies. Most also had damaged or missing
areas, known as lesions, in their left hemispheres, like me. I assume that one
of those data points was mine.
I went to college and
majored in neuroscience. After graduating in 2015, I spent two years working in
a lab studying concussions. I spent hours in the magnetic resonance imaging
room, watching as other peoples’ brains appeared before me on a computer
screen.
But I never thought
much about my own brain until this spring, when I happened upon a story in
Wired magazine (see https://childnervoussystem.blogspot.com/2022/09/perinatal-stroke-2.html) about a woman just like me: astonishingly normal, apart from a
missing temporal lobe.
A Critical Hemisphere
For more than a
century, the left hemisphere of the brain has been considered the center of
language production and comprehension.
This idea was first
proposed in 1836 by Dr. Marc Dax, a physician who observed that patients who
had injuries to the left side of their brains could no longer speak properly.
Twenty-five years later, Dr. Pierre Paul Broca observed a young man who had
lost the ability to speak and could utter only one syllable: “Tan.” A brain
biopsy following the patient’s death revealed a large lesion in the frontal
part of the left hemisphere, now known as Broca’s area.
In the early 1870s,
Dr. Carl Wernicke, a neurologist, saw several patients who could speak
fluently, but their utterances made little sense. One of these patients had a
stroke in the back of her left temporal lobe, and Wernicke concluded that this
section of the brain — now called Wernicke’s area — must serve as a second
center for language, alongside Broca’s area.
Modern brain imaging
studies have further expanded our understanding of language. Much of this work
has shown that two brain regions — the left sides of the temporal and frontal
lobes — activate when a person is reading or hearing words. Some researchers
have called this the “language network.”
But other
neuroscientists have argued that language processing is even broader and not
confined to specific brain regions.
“I believe that
language in the brain is distributed throughout the entire brain,” said Jeremy
Skipper, the head of the Language, Action and Brain Lab at University College
London (and my former college psychology professor).
Studies have shown
that written words can activate the part of the brain associated with the
word’s meaning. For example, the word “telephone” activates an area related to
hearing, “kick” triggers a region involved in moving the legs, and “garlic”
activates a part that processes smells.
The areas of the brain
traditionally attributed to language have lots of other functions, Skipper
said. “It just depends on what other sections of the brain they are talking to
and at what time and in what context.”
Eight Interesting Brains
The Wired article
described an anonymous woman from Connecticut who had no idea she lacked a left
temporal lobe until undergoing an unrelated brain scan as an adult. For the
past few years, the article explained, she had been part of a research project
led by Evelina Fedorenko, a cognitive neuroscientist at the Massachusetts
Institute of Technology.
In April, I wrote
Fedorenko an email telling her about my missing left temporal lobe and offering
to be part of her research. She replied 4 1/2 hours later, and soon I was
booking an airplane ticket from my home in rural Colorado to Boston.
There are currently
eight participants, including me, in Fedorenko’s Interesting Brain Project, she
told me. I haven’t met them, but four of us had presumed perinatal strokes,
resulting in damage to our left hemispheres. Two participants have benign cysts
in their right or left hemispheres, one had a stroke in the right hemisphere,
and one had brain tissue removed from the left hemisphere because of a tumor.
“The brain has
incredible neuroplasticity,” said Hope Kean, a graduate student in Fedorenko’s
lab who is running the Interesting Brain study as part of her dissertation.
It seems that networks
in the brain arrange in a particular way, but if you lose crucial brain regions
as a baby — when the brain is still very plastic — these networks can reroute,
Kean said.
I arrived at
Fedorenko’s lab in Cambridge on a hot day in July. I lay on a bed that slid
into the MRI machine’s narrow tube, with a cagelike device placed over my head.
Kean snapped a mirror onto the headpiece so I could see a screen at the back of
the scanner. As the machine started to make its banging, booming sounds, I
remembered all of the times I had dozed off inside as a kid, lulled to sleep by
its thundering chords.
On the screen, words
flashed quickly and a voice read them aloud, forming random sentences like,
“Just the barest suggestion of a heel is found on teenage pumps.” Then, the
words switched to a haphazard assortment of letters, creating incomprehensible
sounds.
After the scan was
completed, the researchers and I crowded around a computer screen, where I saw
a slice of my brain for the first time. I stared in disbelief, stunned that my
neuronal wiring could have rerouted around this large, oblong hole where my
temporal lobe should have been in the space behind my left temple and eye
socket.
In a typical person’s
brain, the sentences that I heard and read in the scanner would robustly
activate the left temporal and frontal lobes, whereas the nonsense sounds would
not.
The researchers’
studies found that the brain of the Connecticut patient had adapted by
switching sides: For her, these sentences activated the right temporal and
frontal lobes, according to a case study published in the journal Neuropsychologia.
My brain, however,
surprised everyone, yet again.
A preliminary analysis
of the scans showed that, even without a left temporal lobe, I still process
sentences using my left hemisphere.
“I had thought that
any large left hemisphere early lesion leads to the migration of the language
system to the right hemisphere!” Fedorenko said. “But science is cool this way.
Surprises often mean cool discoveries.”
A possible reason
behind this discovery, according to Fedorenko, is that my lesion is primarily
in the front of my left hemisphere, leaving enough healthy tissue in the back
for the language system to take root.
Over the next few
years, I’ll be flying back to the lab for additional scans and tests, and
Fedorenko hopes to recruit even more people with unusual brains to participate
in this study.
I still think about
the study I was in as a young child and about all of the other kids whose
perinatal strokes had left many of them severely disabled. For some mysterious
reason, my brain evolved around its missing lobe, whereas theirs struggled to
do so. Why wasn’t I born with the developmental and cognitive problems, and
they were? Why did my left side rewire to give me the syllables, words and
phrases that have so enriched my life?
It’s these questions
that make me grateful to have been involved in this study — and to be a
research participant once again.
https://news.yahoo.com/curious-hole-head-151127600.html
https://www.nytimes.com/2022/09/04/science/brain-language-research.html
