(Roughly) Daily

The most under-rated of our senses is also the least understood. But as Yasemin Saplakoglu reports, a better understanding of human smell is emerging as scientists interrogate its fundamental elements: the odor molecules that enter your nose and the individual neurons that translate them into perception in your brain…

… Smell is deeply tied with the emotion and memory centers of our brain. Lavender perfume might evoke memories of a close friend. A waft of cheap vodka, a relic of college days, might make you grimace. The smell of a certain laundry detergent, the same one your grandparents used, might bring tears to your eyes.

Smell is also our most ancient sense, tracing back billions of years to the first chemical-sensing cells. But scientists know little about it compared to other senses — vision and hearing in particular. That’s in part because smell has not been deemed critical to our survival; humans have been wrongly considered “bad smellers” for more than a century. It’s also not easy to study.

“It’s a highly dimensional sense,” said Valentina Parma, an olfactory researcher at the Monell Chemical Senses Center in Philadelphia. “We don’t know exactly how chemicals translate to perception.” But scientists are making progress toward systematically characterizing and quantifying what it means to smell by breaking the process down to its most fundamental elements — from the odor molecules that enter your nose to the individual neurons that process them in the brain.

Several new databases, including one recently published in the journal Scientific Data, are attempting to establish a shared scientific language for the perception of molecular scents — what individual molecules “smell like” to us. And on the other end of the pathway, researchers recently published a study in Nature describing how those scent molecules are translated into a neural language that triggers emotions and memories.

Together, these efforts are painting a richer picture of our strongest memory-teleportation device. This higher-resolution look is challenging the long-held assumption that smell is our least important sense…

[Saplakoglu recounts the history of our understanding of smell; explains the current science on how millions of molecules, often in complex bouquets, enter the nose and are processed by neurons to generate a sense of smell that’s deeply emotional and personal; and explores the ways in which it’s intstrumental in attraction, survival, and memory…]

… Because our sense of smell can be largely subliminal, in surveys many people, given the choice of losing one sense, choose olfaction. But “every day, I experience people sitting in my office and talking about how they are disconnected to the world,” [Thomas] Hummel said. They can’t smell their children or spouses anymore. They cannot detect bad-smelling food or dangerous smoke. They no longer have access to certain memories.

“I know the memory is there, but I don’t have the key to open [it] anymore,” Hummel said. “Life becomes a much more insecure place without a sense of smell in many ways, but you only realize it when it’s gone.”…

Fascinating: “How Smell Guides Our Inner World,” from @yaseminsaplakoglu.bsky.social‬ in @quantamagazine.bsky.social‬.

* Helen Keller

###

As we get to know the nose, we might celebrate the avatar of affecting aromas: today is National Cheese Pizza Day.

source