Monday, July 15, 2019

The Chemosensitive Organ

Diving off the deep end, I had an olfactory moment the other night that was a bit amazing, a bit scary. Amazing because I may have unlocked a new dimension of olfactory experience for myself, scary because I might be detecting the first real glimpse of neurological dysfunction that awaits my aged, exasperated mind.

Smells are like that. There are moments when I catch a whiff that is so faint, and so impossible to detect (like the mold that grows on the metal of your umbrella), that I often have to consider the myriad olfactory hallucinations that beset our chemosensitive organ, of which there are many.

It was a hot summer night. The crazy smell experiences always start out like that. Odors love heat, because evaporation is what makes them mobile; heat is the odor motor, if you will.

On this hot, sweaty night, I was eating dinner, hot and sweaty, resting my arms on my high-topped table, when I became fussed over the cleanliness of the surface of my table. My resting forearms sheathed in a thin film of slightly sticky, waxy sebum, and my tabletop layered in a similar compound from previous nights of the same scenario. "I need to clean this damn table. It's gross."

I try to keep my arms off the table. But it's a high top, and it's more comfortable for me to hunch over my bowl of gruel, resting on the underside of my forearms. I keep losing the battle, touching my sticky gross arms to the sticky gross table, then remembering not to, sitting straight up, only to capitulate again moments later.

All the while, I'm sampling my dinner, and very thoughtfully. I tried a new recipe last night, and today are the leftovers. The leftovers always taste different, and for some things, even better. The lemon juice in the marinade, the Maillard on the cast iron; What happened there? I used soy sauce and lime last time. What's the difference now? The acid, more sour; The surface texture, less caramelized. I am thinking, but with my mouth, my nose, lost in gustatory, olfactory thought. Shit! Dirty sticky table! And then it happened. Mid-bite, mid-thought, I could smell the table with my forearm.

That's right, mid-bite, the sensations of my dinner coalesced with the sensations of my forearms, and all of the sudden I could taste the table. Not even sure how to describe the taste, it didn't last long enough. My friend who knows a bit about these things says it's synaesthesia, hallucination. I'm not sure. I don't recall ever reading or hearing about this, but the science of smell is more mystery than science.

Our skin is covered in sensory receptors. Our olfactory cortex is entwined with our immune system. There is a hell of a lot going on here. I'm convinced that the reason I can smell mold in ways nobody else seems to be able to is because I trained (inadvertently through paranoia) my immune system in concert with my olfactory system to recognize it, and after a severe and prolonged exposure event in a basement apartment. The two -- immune and olfactory system -- now work together to alert me to its presence in the most impossibly minute airborne concentrations.

And now, I am suspicious that it goes way deeper. Then again, as I said at the outset, I may be slowly and steadily rolling into cognitive decline, my neural tendrils twisting, knotting, brittle and breaking. At least I'm taking notes.

Pattern recognition receptor (PRR)   
A receptor present on the surface of keratinocytes and other cells of the innate immune system that recognizes microbe-specific molecules that are recognized by a given PRR are called pathogen-associated molecular patterns (PAMPs) and include fungal glucans...They are also called primitive pattern recognition receptors because they evolved before other parts of the immune system, particularly before adaptive immunity...The innate immune system is an older evolutionary defense strategy, relatively speaking, and it is the dominant immune system response found in plants, fungi, insects, and primitive multicellular organisms. 

Thursday, July 4, 2019

The Olfactocracy

No, you don't have to eat your broccoli.

In an experiment that sounds like something we should have done like 70 years ago, we discover that all noses are not created equal. We all smell things differently, perceiving particular odor-features with varying levels of intensity.

I take it back; we didn't have the ability to do this kind of genetics testing 70 years ago. This new experiment showed that of the ~400 genes that control our ~400 different olfactory receptors, the variability is on high. In other words, let's say broccoli has a bunch of different chemicals that make it smell like "broccoli," and that there's a bunch of different receptor-genes that code for those chemicals -- you and I have slightly different versions of those receptors, which make one of us more sensitive to the bad parts of the smell, and maybe even the other of us more sensitive to the good parts.

What you get is one person who doesn't mind eating broccoli, and one of us who gets less ice cream after dinner everytime broccoli's on the menu.

What you also get is an entire sense which lacks in consensus. At the genetic level, what smells good to you won't necessarily smell good to me. So how do we agree?

As groundbreaking a breakthrough as this is, it doesn't even begin to scratch the surface as to how different each of our olfactory experiences are. Each one of us really does live an olfactory world all to ourselves.

We know then that genetics separates us, but it goes even further. Genetics is the hardwiring, but what about the softwiring? If you, for example, were force-fed broccoli while at the same time you're also forced to watch, with your eyes pried open, footage of people trying to peel the foil off a Nutella jar but it rips halfway through, then you might become traumatized by the smell of hot broccoli, and hence highly sensitive, and highly averse to it.

And the reverse can also happen. Don't like Flowerbomb? Wait until you have a few too many romantic encounters with a woman who wears it, and you'll change, you'll see.  That's softwiring. Humans are special because of our neural plasticity, so you can bet we're susceptible to these kinds of changes.

The final note here needs to be on the way we talk about smells. If we all smell a bit different, then how can we really communicate our experiences to each other with any fidelity? 

C. Trimmer, A. Keller, N. R. Murphy, L. L. Snyder, J. R. Willer, M. H. Nagai, N. Katsanis, L. B. Vosshall, H. Matsunami, and J. D. Mainland
PNAS May 7, 2019 116 (19) 9475-9480; first published April 30, 2019

Heather Murphy for the New York Times, May 2019

Thursday, May 16, 2019

Crowd Breath

Environmental surveillance is going to change the way we do things around here.

I'll never forget the day I heard Michio Kaku tell me that my toilet bowl would one day know more about me than my doctor. It was one of the most obvious examples, yet something so benign-sounding that it's never offered as a prediction of the future.

Talking toilet bowls do not make the most clickworthy headlines. Or do they? Maybe I'm not the most prescient clickbait writer. Maybe Google already has a patent on the Smart Bowl. (They do, just checked.)

More examples of environmental surveillance are already among us, like any home security system. These systems are listening to your whole house. They might even be listening to your footsteps with their gait-recognition algorithm-ears.

But today we're here to talk about the ability to measure the collective emotional signature of large groups of people. This particular study is innocuous – it looks at the release of isoprene via our breath, and as a result of the physical agitation that we experience when watching an intense film.

The researchers who came up with this stuck a mass spectrometer (basically a human offgassing detector) inside the HVAC of the movie theater, and roll the film. As the crowd reacts, they involuntarily release chemical signals that reveal their emotional state.

This technique is used to gauge the stress-inducing effects of a film, to thereby classify it for various age groups. We don't want kids watching films that are too intense. But you can easily imagine this being used for a multitude of purposes. For example, imagine a school where every classroom is outfitted with this equipment, monitoring the collective stress levels in every room, ready to dispatch a security guard without the need for a teacher to call the principal's office.

Oct 2018, Ars Technica

C. Stönner et al, PLoS ONE, 2018

The Future of Humanity, new book (2018) by Michio Kaku

Also check out his radio show on WBAI 99.5FM

Nov 2018,

Sep 2017, BBC

Post Script:
All this talk of home security does remind me of the ancient Japanese technique of the Nightingale floorboards, which were a lo-fi security device. The placement of tiny metal strips under the floor rub against each other when you walk on them, chirping your arrival.

Tuesday, April 30, 2019

Breath Tech

The Halimeter measures volatile sulfur compounds in the breath down to the parts per billion, and is used to identify the origin of one's bad breath.

It is a common factoid that body odors, particularly our breath, can be used to detect disease. Diabetes is a good example; it smells like acetone (nail polish), which is a result of the metabolism of excess ketones in the blood, which themselves are a result of the burning of fat instead of sugar, a solution the body uses when it has run out of sugar.

The holy grail of disease detection via the breath would be to identify cancer, and early enough that it can be stopped or reversed.

That's exactly what the Breath Biopsy study intends to develop. A large group of people will be chosen to breathe into a sampling vessel, from which their breath will then be sniffed, i.e., scanned for identifiable patterns, and saved for future reference.

Image source
Those people will be tracked into the future. For those who go on to develop cancer, their breath samples will be compared to those who did not develop the disease. The researchers are ultimately trying to find out how far in advance they can detect the cancer breath. This breathalyzer could then become a non-invasive way to identify the disease.

This painting by visionary artist Alex Grey isn’t about breath but about language. Nonetheless I thought it would look good here.

Jan 2019, CNN

Post Script:
I will repeat again here a story I find fascinating in regards to identifying disease by smell. I certainly cannot tell you that it's true; it's only meant to enliven discussion:

Although it does not happen often, it does happen that large plots of land previously used as a burial ground must get moved. On one of these occasions, after many days of work, the gravediggers (or whatever is the opposite of a gravedigger) reported markedly different smells coming from the many areas of the cemetery. After looking into it, the different odor-areas could be correlated to disease epidemics in history. Dirt that had been home for a hundred years to those who died during the diphtheria outbreak smelled different than that for tuberculosis.

Thursday, April 11, 2019

The City with No Smells

We all know that air pollution is a real threat, both to ourselves and our planet. And we all know that automobiles and electricity generated by fossil fuels are the major contributors to this pollution, and mostly because they are visible (except that they’re really not visible – the plumes you see exhausting from tailpipes and smokestacks tend to be water vapor; the polluting parts are invisibly microscopic.)

But there's another suspect out there which goes largely ignored, and as it would, because it's largely invisible to us.

We're not talking about cow farts, but cooking grease. To be more scientific, it is called organic aerosols, and it comes from the oils and organic matter that are heated in the process of cooking, and ejected out of the kitchen and into our urban environments.

As science starts to zero-in on atmospheric offenders, the local sources of pollution become more apparent. You will be way more exposed to the particulate matter exhausting from a tailpipe if you're driving right behind one, as opposed to watching it from your apartment window. But you are also more exposed to the organic aerosols exhausted from your local taqueria as you walk around your neighborhood, as compared to a pollution meter stationed on the roof of your 4-story apartment building.

So although global pollution is a problem for sure, local pollution is a problem even moreso, and one that needs to be managed in order to raise the quality of life for ever-increasing urban populations.

Thing is, although organic aerosols may be invisible, they are smellable. And although there are plenty of examples of restaurants "polluting" our urban environment with rancid reminders of why Yelp is still in business, there are just as many examples of locale-defining odor profiles marking your travels about your home neighborhood, or your favorite tourist destination.

Popcorn at the movie theater* is an obvious example, but there are plenty more of these olfactory advertisements to enjoy, and which even help to define a neighborhood. It's interesting to think of a historic preservation society that adds to their list of cornices and cobblestones a particular plume that really defines a place – a specific combination of cultural cuisine that can only be found in that little nook where the Polish krautmakers and Indian currystirrers all live together.

That being said, it’s not hard to imagine a future where everything that smells is bad for you and hence ridden. A city with no smells. Very healthy, very uninspiring.

*I was recently informed by a friend that, to him, "popcorn smells like vomit," which does make sense IF the butter is rancid, because isovaleric acid is a primary constituent of rancid butter, and is the smell of vomit and fermented feet sweat.

Nov 2018,

Post Script:
Good smells aside, when you roast things like nuts, popcorn or coffee, some of the compounds released are called diacetyls, which can cause serious respiratory problems for workers exposed to it in high amount.

Thursday, March 21, 2019

Your Mother


Somewhere in England they are now programming smoke alarms with your mother's voice instead of an ear piercing siren, because it gets you out of bed quicker. The precious seconds saved could also save lives.

The reason the sound of your mother's voice can turn on your inner alarm faster than a fog horn, has a lot to do with our nature as social creatures, and of course, our limbic systems.

The limbic system is the part of us that takes flight in a dangerous situation. It is a brain inside our brain, and if it had a brain inside it, that would probably be the amygdala; I'm sure you've heard of it. It also holds the hippocampus, also known as the memory bank.

The limbic system operates beyond our conscious control. It has to, because it's a big part of what keeps us alive before we even become "conscious." It learns from its environment, and responds accordingly. A major part of that environment is the people around us.

Our status as social animals makes us very sensitive to the people around us, and especially those who take care of us, and especially even more those who take care of us when we're young.

This is because our limbic system is, shall we say, very open to suggestion when we're young. It's kind of like a blank slate of a book, or an instruction manual, where every word that's written starts out really big, and gets smaller and smaller as we age.

And who is one of the first people to write in this book? Your mother. She codes her voice so deep into your autonomic nervous system that the sound of it can activate your limbs faster than flash of lightning.

So it only makes sense that if we are looking for a shortcut to the body-control-system, this would be it.

Oct 2018, BBC

Robet Sapolski's Stanford lectures in Human Behavioral Genetics are a great place to learn about this kind of thing; he is a skilled and engaging lecturer.

Post Script
Consider this idea in light of the developments we see today in robotics, or in any instance of digitally-mediated human assistance. Robots that take care of the elderly in the absence of their progeny, or who take care of people of reproductive age in the absence of a mate. The limbic system is a powerful thing, and it will certainly be exploited.

Post Post Script
Elon Musk did a surprisingly interesting job of describing all ^this in his infamous interview on the Joe Rogan show.

Post Post Post
Amygdalic is a word, but it doesn't do what you want it to in this context. It comes from chemistry and it means made of almonds, or rather the amygdalin contained therein. And now you got me started, almonds do also contain cyanide, but not enough to kill you, you robust biological specimen! If you ever had a rotten almond, you can pretend that's the cyanide in your mouth. Not totally sure about that, but there is another species of almond, actually called the bitter almond, that has more cyanide in it, and is also the almond used to make almond fragrance. The amygdala got its name because it is shaped like an almond.

Wednesday, March 20, 2019

Get Minty

Hanging out with some friends the other night, and as bedtime rolls around, I hear my friend say to her son, "Come on, time to get minty."

I had never heard this before, but I knew exactly what it meant. I was excited at the novelty of it, but also that it makes brushing your teeth sound like way more fun than "brushing your teeth."

I was also set wondering why I had never heard this before; it makes so much sense. But my next thought is the one that took hold – why is toothpaste minty?

Today I'm here to tell you why toothpaste is minty; there’s two reasons. One of them makes sense and the other does not.

The easy answer for why toothpaste to this day remains minted lies in the trigeminal properties of mint. The trigeminal sense is not so much a sixth sense, but more like 5 1/2. When things are sensed as spicy-hot or minty-cool, that is the trigeminal sense being activated. This effect creates a habit cycle by making you think your breath is fresh after brushing because your mouth feels cooler.

That's a good reason. But there are other things that produce trigeminal effects. Jalapeno peppers would make a good toothpaste on this account. (Why does it have to be cool?) Then there's cardamom seeds. And fennel. Why isn't toothpaste made of liquorice?

Coincidence, that's why. Mint just happened to be the flavor of the toothpaste to land on Claude Hopkins doorstep. He is advertising's first master manipulator, and the man responsible for the reason we brush out teeth.

I know this might sound crazy, but prior to Pepsodent in the 1900's, people did not brush their teeth. Crazy. We had to be duped into it by a marketing campaign. And dupe he did – 100 years later, here we are, still getting minty before bedtime, every night.

It is unclear as to whether Hopkins knew the power of trigeminal effects in creating a habitual feedback loop. But he definitely understood the concept of the loop.

When his client came to him for help selling his new tooth-paste product, Hopkins spent hours and hours reading about dentistry and oral hygiene, until one small illustration struck him.

A page in the book indicated that there is a film that forms on the surface of your teeth, and all over your mouth. In the dental textbook it's called mucin plaque, but he called it "the film." The film is always there, and it's always been there. But Hopkins was a mental manipulator maximus.

He transformed that factoid thus:

You – run your tongue over your teeth, you feel that? That's a film of gross nasty schmutz that accumulates on your teeth every day. It's gross, and it also makes your breath smell. You like that filthy mouth film? No, no you don't. So why don't you get yourself a tube of Pepsodent, and scrub it right off. There. Feel that mint-flavored freshness? There, all better.

Feeling the film on your teeth was the cue, and having a fresh mouth was the reward. These two work together to rewire your brain until we have a habit. For things like nicotine and smoking, the cue is a physiological imbalance, because nicotine is addictive. But for other things that are not drugs, we must create a habitual loop.

Claude Hopkins knew this, and with this knowledge he set a civilization on the path to oral health. The fact that this path was minty fresh was kind of inconsequential. And since we're here talking about this, I should add that in India, where mouth health has been a big deal for much longer than toothpaste, they have a few different approaches. Cardamom, fennel, and fenugreek are sometimes roasted, sometimes candy-coated, but usually chewed after a meal.

Would fennel toothpaste ever take off? I'll keep my eye out the next time I'm in Trader Joe's, or that little Vermont grocery store.

And now for the final reveal, the first Pepsodent wasn’t even made with Mint, it was made with Sassafras (think Root Beer). I will assume this was categorized as “minty.”  I’m also having a fuzzy recollection that Burt’s Bees makes a clove toothpaste?

How the history of toothpaste explains why you can’t lose weight
Charles Duhigg for Slate

Charles Duhigg wrote a book about habit formation, called The Power of Habit. I wrote about Charles's book in my book called Hidden Scents.