Tuesday, May 11, 2021

A Gloomy Day on Social Media


It snowed a couple of inches yesterday across the Front Range of the Rockies and this morning the lilacs and the aspen saplings at FirstNerve Manor were bent under the icy weight. It’s been dark, overcast, and raining all day long. One stares out the window waiting for something better to happen. Then, just when one begins to reorganize the pencil drawer comes a flash of insight—what a perfect afternoon to weed out the LinkedIn connections!

Some calls are easy—those people you interacted with years ago but whose careers have gone off in entirely different directions from your own. It’s unlikely you will ever have a professional interest in common with them again. So—“Remove Connection.”

Then there are the connections that bring you up short—the old friend who died unexpectedly nearly a year ago. It seems callous to delete the link, but even a candle lit in his memory would eventually burn out. (“Remove Connection.”) Then the likeable guy you pitched some business with before he dropped dead after a squash game a decade ago. You went to his funeral and memorialized him here. Does a persistent online link express anything further? (“Remove Connection.”) Ditto the former client’s late husband who you liked and respected.

Even more depressing is to find the connections who, once in senior positions, are now retired. One thinks, uncharitably, that they are now just taking up virtual space in your LinkedIn connections. (“Remove Connection,” “Remove Connection,” etc.)

The same goes for academics who have levitated themselves into “emeritus” status. (“Remove Connection.”) And then, a long-ignored discontent bubbles up—why link to any academics at all? Professors are easily found via their campus web pages. Basta. (Three more “Remove Connections.”)

The late afternoon sun has broken through and the birds are singing once again. The virtual thicket has been thinned out and is ready to welcome new tendrils of professional linkage. Time for a drink.

Saturday, May 8, 2021

Yeah, About That TPS Report Cover Sheet . . .


Unlike ex-Initech employee Peter Gibbons, I’m a fan of TPS reports. That is to say, studies of terpene synthases (TPS) in cannabis. These are the plant enzymes that turn precursor molecules into the various fragrant terpenes behind each strain’s aroma profile. Some TPS enzymes convert geranyl diphosphate into a slew of monoterpenes, while others convert farnesyl diphosphate to a bunch of sesquiterpenes.

Identification of cannabis terpene synthases and the genes that produce them is a relatively new field. Canadian researchers led by Judith K. Booth at UBC in Vancouver were early leaders in this effort and last fall they published another study. This one, in Plant Physiology, was the subject of a “news and views” piece in the same issue, written by Marc-Sven Roell at the Heinrich-Heine University in Düsseldorf.

Like Bill Lumbergh, I have some issues with Roell’s TPS report cover sheet. Specifically, with his claims about what is required for future cannabis breeding efforts aimed at fragrance and flavor.

To predict and design cannabis smell and taste to meet consumer demands, two milestones have to be reached. First, a comprehensive understanding of terpene composition is required, which can be achieved by using quantitative terpene profiling in existing cultivars. Second the underlying molecular and biochemical mechanisms leading to these distinct profiles need to be understood.

Roell insists that we must first know everything about terpenes in all cultivars—their complete chemical composition plus their physiological means of production—before we can get around to breeding hybrids with specific consumer appeal.

Notice anything missing? How about sensory evaluation of the smell and taste of the existing cultivars? And how about relating perceived aroma to differences in terpene composition?

Roell no doubt expects to find cultivar to cultivar differences in terpene composition, which he assumes will equate to differences in aroma and flavor. But differences in chemical composition don’t necessarily translate into perceptible differences in aroma, much less differences that are meaningful to cannabis consumers. So his strategy of starting with comprehensive knowledge of terpene composition will be enormously inefficient.

This objection also cuts in the opposite direction. As a plant physiologist, Roell ought to know that even within genetically identical clones, terpene composition can vary with growing conditions. Thus, it is possible that within-clone variation could result in perceptible aroma differences.

So either way you look at it, Roell’s insistence that baseline chemical data is an absolute prerequisite for breeding better smelling cannabis is pretty weak, especially when he totally neglects sensory measurement.

In fact, I’d argue that the best way to assist breeding efforts is begin with quantitative sensory evaluation of a range of existing cultivars. Next, cross-tabulate aroma profiles with sales and consumer preference data to obtain a ranking of most-valued sensory traits. Go back to your list of cultivars and start hybridizing for likely winners. It’s the purely phenotypic selection method that worked very well for Luther Burbank in the days before gene sequencing and gas chromatography. This approach would get the program going a lot faster than Roell’s “study the hell out of everything before making a move” strategy. I think he has it totally backwards—sensory analysis should precede chemical analysis.

“Hello Marc-Sven, what’s happening?

We have sort of a problem here. Yeah, you apparently didn’t include sensory analysis in your new cover sheet on the TPS report.

Did you see the memo about this?

Yeah, if you could just go ahead and make sure you do that from now on that would be great. 

And I’ll go ahead and make sure you get another copy of that memo.”

The study discussed here is “Terpenes in Cannabis: Solving the puzzle of how to predict taste and smell,” by Marc-Sven Roell, published in Plant Physiology 184:8-9, 2020.

Wednesday, April 28, 2021

Smells from Beyond


In a series of pre-Halloween posts a decade ago, I examined ghostly smell stories and poems including examples from the Victorian English novelist Wilkie Collins, the 19th century American writer Bret Harte, the Irish poet W.B. Yeats, and an English novel (“The Uninvited”) that was made into a movie starring Ray Milland.

I was reminded of them this week when I came across a new study: “Perceptual phenomena associated with spontaneous experiences of after-death communication: Analysis of visual, tactile, auditory and olfactory sensations.”

Have I started dabbling in occultism? Not exactly. The paper appears in Explore: The Journal of Science & Healing, published by Elsevier, which claims to address “the scientific principles behind, and applications of, evidence-based healing practices from a wide variety of sources, including conventional, alternative, and cross-cultural medicine.” Further, “It is an interdisciplinary journal that explores the healing arts, consciousness, spirituality, eco-environmental issues, and basic science as all these fields relate to health.”

OK, then!

So who conducted the study? Here’s the batting order:

Marjorie Woollacott, an emeritus professor of physiology whose focus is motor control.

Chris A. Roe, a professor of psychology at the University of Northampton in the UK who is President of the Society for Psychical Research and whose most recent publication is a chapter titled “Clinical parapsychology: The interface between anomalous experiences and psychological wellbeing.”

Callum E. Cooper, a senior lecturer in psychology at Northampton, who holds two doctorates and whose most recent publication is the entry on “Anal Intercourse” for the Encyclopedia of Sex and Sexuality.

David Lorimer, Programme Director of something called the Scientific and Medical Network, and an editor and author of many books including Survival? Death as a Transition; he is interviewed in a recent youtube video.

Evelyn Elsaesser, an independent researcher in Switzerland and author of, among other books, On the other side of life: Exploring the phenomenon of the near-death experience.

So what have they delivered?

The study itself consists of a lengthy 194-item online questionnaire that was filled out by 991 people, mostly women (85%) with a median age of 51 years. The olfactory data appear in Table 6. In response to the question “Did you smell a fragrance characteristic of the deceased which made you think he/she was present?” 28% of respondents said yes. Of these, 60% also said yes to the next question: “Did you feel that the deceased was conveying a message to you by way of this fragrance?”

The authors give us an idea of what smells were reported:

“The fragrances typically included aftershave lotion, a typical body scent, perfume or soap, but many odors were noted in the descriptions, including tobacco, food and flowers.”

Smells were the least common sensory impression (28%) reported by people who experienced ADC. The most frequent were tactile (48%), visual (46%), and auditory (44%). While noting that there is considerable variability in the representation of the individual senses in previous studies of ADC, the authors don’t have much to say about the proportions they found.

For what it’s worth, I would point out that the substantially lower incidence of smells compared to sights and sounds is consistent with what’s been reported for sensory impressions in dreams and hallucinations.

The paper is mildly interesting for the cross-sensory tabulations insofar as they relate to smells in phantosmia, dreams, and hallucinations. Whether there is anything else worth pursuing on the topic of after-death communication is, in my opinion, dubious. Interestingly, the funders of the study are publicity-shy:

Funding: This work was supported by a foundation that wishes to remain anonymous. The funding organization had no influence on the final research design, data collection, analysis, interpretation of data, the writing of the report or the decision to submit the article for publication.

UPDATE May 7, 2021

And right on cuespooky new Netflix movie Things Heard & Seen features among other things a smelly ghost.

The study discussed here is “Perceptual phenomena associatedwith spontaneous experiences of after-death communication: Analysis of visual,tactile, auditory and olfactory sensations,” by Marjorie Woollacott, Chris A. Roe, Callum E. Cooper, David Lorimer, and Evelyn Elsaesser, published online in EXPLORE, February 23, 2021.

Thursday, April 22, 2021

Keeping Up with the News

I’ve tracked new scientific findings about the human sense of smell for a long time. Rather than just file them away for my own interest, I posted one-sentence summaries of clinically relevant findings to the Disorders of Odor Perception website at hyposmia.com. I was doing so on a more or less weekly basis until about a year ago when covid hit the fan and disrupted my routine along with everyone else’s.

Over the course of the year, “regular” publications on smell science were overwhelmed by a flood of papers on covid-related smell loss. I tried to keep up with these for while, but it was simply too much to handle and eventually I stopped updating the site.

Recently, when I decided to resume posting new material to Disorders of Odor Perception, it occurred to me that the web design was hopelessly out of date: the site looked OK on laptops, but was barely legible on phone or tablet. So I redesigned the site to make it “responsive”, i.e., it adapts to the device you view it on and is (hopefully!) much easier to read on mobile devices.

As before, new content appears in three categories: Smell Loss (hyposmia and anosmia); Smell Distortion (parosmia, phantosmia, etc.); and News & Reviews.

I also updated the format of the “new content” emails. They now contain direct links to the original source items—no need to go back to website to find them. This ought to make the emails much more user friendly.

If you are a clinician or patient or just interested in the topic of smell disorders, I encourage you to sign up for the email alerts. It’s a painless way to keep up with new work in the field.

Sunday, April 18, 2021

Pardon Me, Do You Have Any Mouse Poupon?

Here’s a tasty new offering from researchers at the Centre des Sciences du Goût et de L’Alimentation in Dijon, France: “Male mice and cows perceive human emotional chemosignals: a preliminary study.”

How do you know if a mouse is perceiving chemosignals of human fear? It poops out more fecal pellets.

How do you know if a cow prefers chemosignals from nonstressed humans? It spends more time smelling the bucket that contains them.

How do you obtain these wondrous human chemosignals? The old cotton pads in the underarms gambit. You get some engineering students to abstain from stinky food and perfume for a few days (major sacrifice—this is France, after all) and wear the pads during a regular class (non-stress) and during an exam (stress).

What can say? I admire the weirdness of the experimental design. I wonder if members of the ethics panel of the French Ministry of Higher Education and Research managed to keep a straight face during the review meeting.

Sidebar: The title of the paper mentions “male mice” and “cows,” when in fact the animals used were male mice and nulliparous female bovines. Shit-kicking American readers would expect “male mice and heifers,” but evidently the heifer vs cow distinction isn’t recognized in the editorial offices of Animal Cognition.

And finally, with apologies to the man from Nantucket:

There once was a heifer from Dijon,
Whose nostrils scientists seized on,
She found it a balm,
When the students smelled calm,
And the researchers gained a citation.

The study discussed here is “Male mice and cows perceive human emotional chemosignals: a preliminary study,” by Alexandra Destrez, Morgane Costes‑Thiré, Anne‑Sophie Viart, Floriane Prost, Bruno Patris and Benoist Schaal, published online in Animal Cognition, April 11, 2021.