Authors: Molly Birnbaum
“The lock and key analogy isn’t perfect,” Stuart Firestein, a leading olfactory scientist and professor of neurobiology at Columbia University, told me. “But it’s close.” He was sitting over a plate of cheese at a table at Le Monde, a warmly lit restaurant across the street from Columbia’s campus. He cupped his left hand, folding it into the shape of a small vase. He extended the index and middle fingers of his right one out straight and moved them slowly into the depth of the pod to show me how a molecule and receptor would bind. This, he demonstrated, is how they come together in the nose. Like pieces in a complicated puzzle, when a match is found, a connection is made and signals are fired. But how, exactly, that match is made remains unknown.
I asked him about how the brain makes sense of the signals sent by the receptors. That’s another unknown, he said. We do know that each of the receptor neurons—millions of them, scattered haphazardly through the epithelium, a small piece of tissue in the nasal cavity—always sends its signals to the same spot in the olfactory bulb where it connects with other similar signals in little bundles of neuronal connections called
glomeruli
. But the understanding ends there. We don’t know what kind of pattern is formed, or how it is read.
“Olfaction is one system without a special map,” Firestein said. “It demands for us to think in a different way.”
Significant advance has taken place in the last two decades. Scientists Richard Axel and Linda Buck published a groundbreaking paper in the scientific journal
Cell
in 1991, for which they later won the Nobel Prize in Medicine. They found that the olfactory receptors were determined by genetics.
The gene family for olfaction, they discovered, is inordinately large. Working with mice, and later transferring their understanding to humans, they identified a family of upward of one thousand different genes devoted to smell, or close to 3 percent of all those in humans. They found that each olfactory neuron only expresses one type of olfactory receptor gene, which means that each neuron only recognizes a select few odorants in the nose. A large percentage of those genes, it turns out, are called
pseudogenes
and do not produce working receptor proteins, leaving humans with around 350 rather than 1,000.
Axel and Buck’s discovery, and subsequent award, brought attention to the science of olfaction, which was then a tiny and unfashionable field. Theirs was an important step toward understanding the biology behind olfactory perception, a complicated process that begins with the static but silent beat of the neuron and can end with the conscious flourish of mood.
“Axel and Buck changed the way olfaction was looked at,” Firestein told me. This was in part because their discovery peeled away one thick layer of the mystery surrounding the science of the nose. Even more, though, it was because their work inspired buzz—in the media, in the scientific community. It created international excitement. This, in the world of olfactory science? Not a usual thing. Suddenly, there was more room for funding. Rising scientists who would otherwise have gravitated toward a different field were drawn toward the nose. Questions were raised. Studies began. The field expanded.
This development was important, Firestein explained, because the science of olfaction is a new model system. “This means that olfaction can be used to make generalizations on how other parts of the brain work. If we can understand how each neuron expresses one olfactory receptor gene and only one gene, or how the neurons regenerate, or how the brain organizes and processes each smell, then perhaps we can understand how other areas of the brain function.”
On my laptop, I watched a video recording of the 2004 Nobel lecture given by Axel, a tall, thin man who bent over the podium like a reed. He spoke about the far-reaching implications of his and Buck’s discovery. “Molecular biology and genetics,” he said, “could now interface with neuroscience to approach previously tenuous relationships between genes, behavior, cognition, memory, emotion, and perception.”
HOWEVER MY BRAIN
processed smell, however it allowed me to understand the significance of stock or perfume, it ended when I smashed my skull against the windshield of that car on that August morning. Suddenly, it didn’t matter how my olfactory receptors attached to those poultry-rich molecules. There was nowhere for the signals to go. When my head hit the car, my brain had bounced against the inside of my forehead. With that impact, there was friction. My brain rubbed against the cribiform plate and sheared off the little neuronal endings coming toward it, like a lawn mower over grass. In effect, the impact severed the neurons that connect my nose to my brain. Like the tendon in my leg, they snapped and then receded. No longer could patterns of smell be sent to my brain. With that split-second crash, my sense of smell vanished.
I had a complete case of
anosmia,
the clinical term for the lack of ability to perceive smells. Years later, I took the train to Philadelphia to speak with Beverly Cowart, who was the Scientific Director of the Monell-Jefferson Taste and Smell Center, one of a small handful of clinics devoted to those with disorders of olfaction and gustation until it closed in 2010, and to her colleagues at the Monell Chemical Senses Center, a nonprofit institute dedicated to the scientific study of taste and smell. It was a bright, clear day and I approached the center, tucked off to the side of the University of Pennsylvania campus in a thick brick building, carrying a bag of notebooks and my digital recorder. I paused for a moment in front of the statue guarding its entrance. It was the fragment of a face by artist Arlene Love, sparkling gold and as tall as the door. The forehead and eyes looked as though they had been ripped off, torn like paper ready for the trash. The disembodied nose, dimpled chin, and lips slightly agape looked mournful and forbidding at the same time. Standing there I felt apprehensive, like I was about to rip the bandage off a very deep wound.
Here we go,
I thought, as I walked in.
Cowart has seen hundreds of cases of anosmia since 1986, when the center opened. She has seen well over one thousand cases of
hyposmia,
or a severely reduced sense of smell. She’s seen those with olfactory distortions, for whom the once-familiar scent of butter cookies baking in the oven can turn hard and metallic, like aluminum. She’s seen those with ghostly smell sensations that come from nowhere but within, those known as phantoms. She told me that there has never been a comprehensive study done on the number of those affected by loss of smell in the United States. But numbers in various scientific studies have estimated that 1 to 2 percent of the population under the age of sixty-five has a disorder of some kind, a number that spikes with age. In Sweden, Cowart told me, a study was published to say that 19.1 percent of the population between the ages of twenty and ninety suffered from some kind of olfactory malfunction, while 5.8 percent were fully anosmic. So there must be millions of people around the world with a lost, distorted, or severely muted sense of smell.
Cowart has seen those who have watched scent gradually melt away, the aroma of coffee brewing weaker each morning, and those who lost it in an instant. For a great number, the cause remains a mystery. But, Cowart says, the “three most common problems we see are either related to ongoing nasal sinus disease, to a prior upper respiratory infection, or to head trauma.”
After the accident, it would be years before I met anyone who also couldn’t smell. It would be years before I understood the breadth of my invisible loss. But Cowart knew: I wasn’t alone.
I RECOVERED FROM
knee surgery in my father’s home in New Hampshire, a condo he had decorated in schemes of burnt umber and oak. Autographed posters of baseball players I didn’t recognize hung next to oil portraits painted by my grandfather, an accomplished amateur.
It was the second condo my father lived in since my parents had divorced. The first was a dark and musty cluster of rooms in the suburban town where my brother and I grew up. I hated that place and when I was there, I would shut myself in my room with my nose in a book, breathing in the faint comfort of paper, the smell of school.
My father moved into the second condo three years later, when I was a senior in high school and living full-time with my mother. This one stood on the edge of a golf course, next to a tiny lake that shimmered in the late-afternoon sun. I visited him there for the first time just after he arrived. I hadn’t wanted to go. I was angry with him, a porous animosity that I had clung to since I was fifteen, when, on that cold November weekend, my parents sat my brother and me down on the couch to tell us they were getting divorced. They told us kindly, standing together over a basket of unfolded laundry on the couch. My father moved out the next day.
I hung back as my father, who looked happy if a bit uncomfortable, walked me from room to room—all of which, I noticed, smelled new. Too new, like floor polish and Clorox, like rug and gleaming kitchen metal. The condo smelled of the soft leather on the couch and the fresh coat of paint on the walls. It was an alien smell, an unwelcome one. It didn’t smell anything like my father.
But what
did
he smell like?
I wondered as I sat stiff backed at the kitchen table after the tour. Not right then. Of course I could smell the present. I could smell the damp pile of leaves on my father’s lawn, the laundry detergent in his hugs, and the old fabric seat in his car. I could smell the soap-scrubbed present, the one wearing golf shoes studded in clumps of dirt. But our past?
There were physical reminders in his new home: the walnut bookcase that had once stood in our living room, next to the piano I halfheartedly played for years. There was the record player on which my father used to blast Led Zeppelin and Jimi Hendrix when I was in kindergarten, dancing a glorious mad trot while I stood on his feet, holding his hands and bouncing up and down. There was that Oriental rug that once lay in the hallway by the garage, and his massive collection of books on the history of war. There were pictures of my brother skiing on a steep mountain slope, my grandparents mugging for the camera in Florida, my father and Cyndi on a vacation somewhere warm. Everything seemed out of place, stone cold and silent, separated from our shared past with things unsaid.
“So what do you think?” he asked. He looked hopeful.
“It’s nice.”
“It still needs work,” my father added almost apologetically.
Pause.
“Maybe you’ll spend more time here?”
I nodded. “Sure.”
But his condo smelled like paint and bleach. It was filled with memories that felt far away and empty. I sat at the table not sure how to relax.
This will never feel like a home,
I thought.
I returned to the condo in the week after knee surgery, my mind hazy from both pain and medication. The four years since my father moved in had dulled the potency of my anger, rendering it a tiny trickle easier to ignore. We had been spending more and more time together as the years progressed. I didn’t hesitate to stay a few weeks recovering under his roof.
When I arrived this time, I didn’t notice the smell of the condo—a smell that in the years since my father had moved in had expanded to include the dark wood and char of the fireplace and home-ground coffee trickling into the large pot he brewed each morning. I didn’t think about my past or my father’s past, one that smelled like jars of basil pesto or plates of lox and eggs and onions, the extent of his kitchen expertise; like the troughs of Grape-Nuts cereal he ate every morning.
I didn’t notice that my father’s plants, which he had maintained with precision since I was small, no longer boasted their aroma of wood and leaf, their bright neon green, because I couldn’t move myself off the bed alone. I didn’t notice that the potent lavender shampoo was as odorless as a bottle of water because I was afraid of the shower, and whenever I sat on a rickety plastic stool under the nozzle, my bandaged leg encased in plastic bags, I could hardly breathe because of the fear of falling, of moving, of feeling more pain. I didn’t notice that the sheets had lost their lemony clean or that the bandages on my scab-encrusted knee smelled so ripe when the doctor changed them I should have had to choke back a gag.
I thought that the veil separating me from my environment would lift when my knee began to heal and I was no longer under the numb influence of the pills I popped every few hours. I thought that the pain and the drugs were what kept me from engaging with my stepmother’s plate of crisp-roasted chicken or the mouthwash I swished back and forth across my tongue.
But then Cyndi made the apple crisp and I realized that everything had changed.
My father sat by my side most nights. We watched movies and news programs. He read; I slept. He brought cloves of garlic and open bottles of cinnamon and clove, basil and oregano. He held them under my nose and asked me to sniff.
“Anything?” he asked.
“No.”
“How about this?”
“No.”
I remembered the hours I’d spent peeling cloves of garlic in the restaurant earlier that summer, their aroma billowing up around me and clinging to my palms for days. But I didn’t cry. I shook my head and looked down at my lap. My emotions had drifted off along with the smell of my father’s aftershave.
I spent most of my time in bed staring out the window. I could see the small lake out back, which hung low in the dry weather. Green-gold reeds grew around its banks and ducks waddled to and from its shore. I sat with my leg swathed in thick bandages and a brace, my pelvis aching and my back muscles in constant spasm, and watched the leaves on the trees turn from green into deep shades of red and yellow. The seasons had changed.
For me, the slow drip of the summer turning into fall had always held the strongest allure of all the New England seasons. Autumn never failed to feel new, reminiscent of crisp notebooks and freshly sharpened pencils. Tart apples, hot cider, and the smell of pumpkin seeds roasting in the kitchen made
me
feel new. I had been apple picking every year in the orchards near my childhood home, breathing in the scent of wet earth and fermented apples left to fall. Halloween had smelled of chocolate and peanut butter, tiny twists of smoke from candles on porch steps, the staccato burst of fruit lurking under the caramel-coated globe. Autumn was when my family began to build fires in the fireplace, the sweet smell of smoke and burning wood inviting me in for warmth.