TIME IN MINDFULNESS
In “Ultrasound Meditation” [Advances], Lucy Tu reports on a study by Brian Lord of the University of Arizona and his colleagues on using brain stimulation to enhance mindfulness, published in Frontiers in Human Neuroscience. The article is thought-provoking. The pioneering work at the University of Wisconsin–Madison and elsewhere using functional magnetic resonance imaging and other techniques to try to elucidate the neurophysiological correlates of deep meditation experience has been invaluable. Now Lord and his group are adding targeted ultrasound stimulation of the brain’s default mode network (DMN) to the tools of potential value in this endeavor.
Most practitioners of deep meditative practices welcome these studies. But a word of caution is in order for those who, like the study authors and Tu, use descriptions of “subjective effects” of deep meditative states. Personal, even “scientific,” bias can creep in. Among the subjective effects of the ultrasound stimulation that were cited in the article, I was most concerned with the phrase “distorted sense of time” (which reflected language used in the study). The somewhat common experience of the “nonlinearity” of time by seasoned meditators is certainly different from the day-to-day experience in the relative world in which we live. But which of those senses of time is “real,” and which is “distorted”? If it turns out, as some suspect, that spacetime itself is in fact subject to the laws of quantum physics, perhaps “alternative” rather than “distorted” might be a better description.
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THOMAS LONG SCOTTSDALE, ARIZ.
“A word of caution is in order for those who use descriptions of ‘subjective effects’ of deep meditative states. Personal bias can creep in.”
—Thomas Long, Scottsdale, Ariz.
LIFE IS A BAG
As a longtime student and practitioner of pathology, I found Bethany Brookshire’s essay “The Human Body Is Made of Bags” [Forum; June 2024] an amusing and appealing approach to anatomy. To take her analogy further, every anatomical “bag,” from the smallest vesicle to the largest exterior surface, has openings and doors. It is at these openings that most, if not all, life processes are enabled.
On a macroscale, mouths, noses, pores, eye lenses, anuses, and so on are where all the interactions we have with our outside world occur. On an organ level, these openings enable the exchange of nutrients, gases, toxins, electrolytes, and thus everything we consume and excrete. Microscopically, cells, vesicles, and all variety of enclosures have openings, and these are usually controlled transporters. Ultimately function follows form at all levels.
JAMES EASTMAN MADISON, WIS.
PATTERNS ALL AROUND YOU
“Cosmic Pareidolia,” by Phil Plait [The Universe], emphasizes that humans’ tendency to interpret random visual patterns as something familiar often results in our seeing faces in particular. But such phenomena are not limited to faces or even to sight. I have a tile on my bathroom floor that shows a very convincing deer’s head when viewed from one angle and the head, leg and foot of a crocodile from another. A gentle breeze in the trees or other quiet background sounds may be whispered voices that can’t quite be understood or music that seems familiar.
JOHN RUSS VIA E-MAIL
GOLDEN TOURING KEY
“How Many Routes,” by Heinrich Hemme [Advances; July/August 2024], presents Henry Ernest Dudeney’s classic traveling-salesman puzzle from 1917. The “golden key” to solving the puzzle is typically ridiculously obvious, but just try finding it! Here we need only sketch in those road segments that must be traveled for all possible paths, namely, those segments attached to cities connected only by two roads. That golden key not only quickly gives us the answer (one path) but also provides the fun of constructing that path out of the mishmash of roads.
Years ago a friend asked me about a variation of the “knight’s tour” problem, in which a chess knight begins on a square of its choosing and hops through all the remaining squares without repeating a square. Would that task be possible on a rectangle smaller than the standard 8 × 8 chess board? Given the knight’s odd move, it was not obvious that a tour would be possible on any such rectangle. A slightly tarnished version of the above golden key, requiring additional work, showed a solution for 4 × 5 and 3 × 4 rectangles. There was no solution for some of the others.
DAVE E. MATSON PASADENA, CALIF.
COLD COMFORT
“Taking the Plunge,” by Jesse Greenspan [Advances; June 2024], reports on research on the perceived benefits of cold-water swimming. For those who, like myself, consider swimming in frigid water a near-death experience, the humble cold shower provides an interesting alternative.
Cold showers are a form of hormesis, a phenomenon in which a stress that is harmful at high doses has a beneficial effect at low doses. As with cold-water swimming, data showing the benefits of cold showers are weak, but the feel-good and energizing dimensions are widely acknowledged. And one can at least minimize temperature shock by slowly adjusting the heat of the water. Maybe most important, the technique is available at home to most everyone 24/7.
RICHIE LOCASSO HEMET, CALIF.
THE GREATEST BUZZ
I enjoyed reading “Keeping Time” [Advances; June 2024], Meghan Bartels’s piece on the emergence of two periodical cicadas, the 13-year Brood XIX and the 17-year Brood XIII, in the spring of 2024.
Here in the western suburbs of Chicago, the cicada party would begin slowly each morning with the distant “Star Trek phaser” drone of the 13-year insects and some local individual buzzes of the 17-year ones. Within hours any favored tree at the site was a rock-concert cacophony of sound that rose and fell as thousands of individuals sang in unison.
LORINDA GUENTHER-WRIGHT CHICAGO
CLARIFICATION
“Hypochondria’s Serious Toll,” by Joanne Silberner [December 2024], referred to the same condition as both “somatic symptom disorder” and “somatic system disorder.” These terms are used synonymously, but somatic symptom disorder is the official diagnosis in the latest edition of the Diagnostic and Statistical Manual of Mental Disorders.
ERRATA
In “Fate of the Hybrid Chickadees,” by Rebecca Heisman, the first photograph of a chickadee should have been credited to Teresa Kopec/Getty Images, and the last photograph of one should have been credited to GeoStills/Alamy Stock Photo.
“Buried at Sea,” by Jaime B. Palter [December 2024], should have said that early results from the field trial of marine carbon dioxide removal in Halifax Harbor off Nova Scotia suggest that the trial moved additional carbon from the atmosphere into the ocean.
In “When Horse Became Steed,” by William T. Taylor [December 2024], an image caption incorrectly described the location of Novoil’inovskiy. It is in Kazakhstan.
