Vagus Nerve - Spouse Effects - Worm Connectome - Evolving Bipedalism

[Breedlove, S]

https://www.quantamagazine.org/how-our-longest-nerve-orchestrates-the-mind-body-connection-20240826/



By R. Douglas Fields

It is late at night. You are alone and wandering empty streets in search of your parked car when you hear footsteps creeping up from behind. Your heart pounds, your blood pressure skyrockets. Goose bumps appear on your arms, sweat on your palms. Your stomach knots and your muscles coil, ready to sprint or fight.

Now imagine the same scene, but without any of the body’s innate responses to an external threat. Would you still feel afraid?

Experiences like this reveal the tight integration between brain and body in the creation of mind — the collage of thoughts, perceptions, feelings and personality unique to each of us. The capabilities of the brain alone are astonishing. The supreme organ gives most people a vivid sensory perception of the world. It can preserve memories, enable us to learn and speak, generate emotions and consciousness. But those who might attempt to preserve their mind by uploading its data into a computer miss a critical point: The body is essential to the mind.

How is this crucial brain-body connection orchestrated? The answer involves the very unusual vagus nerve. The longest nerve in the body, it wends its way from the brain throughout the head and trunk, issuing commands to our organs and receiving sensations from them. Much of the bewildering range of functions it regulates, such as mood, learning, sexual arousal and fear, are automatic and operate without conscious control. These complex responses engage a constellation of cerebral circuits that link brain and body. The vagus nerve is, in one way of thinking, the conduit of the mind.

How could stimulating a single nerve potentially have such wide-ranging psychological and cognitive benefits?

Nerves are typically named for the specific functions they perform. Optic nerves carry signals from the eyes to the brain for vision. Auditory nerves conduct acoustic information for hearing. The best that early anatomists could do with this nerve, however, was to call it the “vagus,” from the Latin for “wandering.” The wandering nerve was apparent to the first anatomists, notably Galen, the Greek polymath who lived until around the year 216. But centuries of study were required to grasp its complex anatomy and function. This effort is ongoing: Research on the vagus nerve is at the forefront of neuroscience today.

 © 2025Simons Foundation

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https://www.nature.com/articles/d41586-025-02772-8

Spouses tend to share psychiatric disorders, massive study finds

    Mohana Basu 

People with a psychiatric disorder are more likely to marry someone who has the same condition than to partner with someone who doesn’t, according to a massive study1 suggesting that the pattern persists across cultures and generations.

Researchers had previously noted this trend in Nordic countries, but the phenomenon has seldom been investigated outside Europe until now.

The latest study, published in Nature Human Behaviour today, used data from more than 14.8 million people in Taiwan, Denmark and Sweden. It examined the proportion of people in those couples who had one of nine psychiatric disorders: schizophrenia, bipolar disorder, depression, anxiety, attention-deficit hyperactivity disorder, autism, obsessive–compulsive disorder (OCD), substance-use disorder and anorexia nervosa.

Scientists lack a definitive understanding of what causes people to develop psychiatric disorders — but genetics and environmental factors are both thought to play a part.

The team found that when one partner was diagnosed with one of the nine conditions, the other was significantly more likely to be diagnosed with the same or another psychiatric condition. Spouses were more likely to have the same conditions than to have different ones, says co-author Chun Chieh Fan, a population and genetics researcher at the Laureate Institute for Brain Research in Tulsa, Oklahoma.

“The main result is that the pattern holds across countries, across cultures, and, of course, generations,” Fan says. Even changes in psychiatric care over the past 50 years have not shifted the trend, he notes.

Only OCD, bipolar disorder and anorexia nervosa showed different patterns across countries. For instance, in Taiwan, married couples were more likely to share OCD than were couples in Nordic countries.
© 2025 Springer Nature Limited

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https://www.thetransmitter.org/connectome/worms-help-untangle-longstanding-brain-structure-function-mystery/

 Worms help untangle brain structure/function mystery

By Holly Barker

When scientists produced the first map of all synaptic connections in the roundworm Caenorhabditis elegans in 1986, many hailed it as a blueprint for the flow of brain signals. As it turned out, though, models of neuronal activity based on this wiring diagram bore little resemblance to the functional maps of brain activity measured in living worms.

This disconnect isn’t limited to worms. Mice, for instance, appear to have widespread silent synapses—wired connections that don’t send signals—and the actual responses of some cells in the fruit fly’s visual system do not match the responses the connectome predicts.

A new preprint helps to explain why: Most network features, in C. elegans at least, are not conserved between the anatomical and functional connectomes. Yet the anatomical connectome can still forecast—albeit in a complex way—observed neuronal activity in the worms, according to a second preprint by the same team, because “most signaling is happening along the wires,” says Andrew Leifer, associate professor of physics and neuroscience at Princeton University and principal investigator on both preprints.

The findings begin to address the long-standing challenge of reconciling structure and function, and show that “we weren’t entirely wrong” about the importance of synaptic connectivity, says Jihong Bai, professor of basic sciences at the Fred Hutchinson Cancer Center, who was not involved in the work.

The debut of a color-coded map of cell types in the worm brain in 2021 split the neuroscience community. It made it possible to identify individual neurons in whole-brain recordings and compare annotated recordings with the connectome—an exercise that revealed no correlation between the two.


© 2025 Simons Foundation
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https://www.nytimes.com/2025/08/27/science/human-evolution-ilium-bipedal.html

Uncovering the Genes That Let Our Ancestors Walk Upright

By Carl Zimmer

Charles Darwin unveiled his theory of evolution in 1859, in “On the Origin of Species.” But it took him another 12 years to work up the courage to declare that humans evolved, too.

In “The Descent of Man,” published in 1871, Darwin argued that humans arose from apes. And one of the most profound changes they underwent was turning into upright walkers.

“Man alone has become a biped,” Darwin wrote. Bipedalism, he declared, was one of humanity’s “most conspicuous characters.”

Scientists have now discovered some of the crucial molecular steps that led to that conspicuous character millions of years ago. A study published in the journal Nature on Wednesday suggests that our early ancestors became bipeds, as old genes started doing new things. Some genes became active in novel places in the human embryo, while others turned on and off at different times.

Scientists have long recognized that a key feature for walking upright is a bone called the ilium. It’s the biggest bone in the pelvis; when you put your hand on your hip, that’s the ilium you feel.

The left and right ilium are both fused to the base of the spine. Each ilium sweeps around the waist to the front of the belly, creating a bowllike shape. Many of the leg muscles we use in walking are anchored to the ilium. The bone also supports the pelvic floor, a network of muscles that acts like a basket for our inner organs when we stand up.

As vital as the ilium is to everyday life, the bone can also be a source of suffering. The ilium can flare up with arthritis, grow brittle in old age, especially in women, and fracture from a fall. Genetic disorders can deform it, making walking difficult. The ilium also forms much of the birth canal — where babies can sometimes get stuck, endangering the mother’s life.

    © 2025 The New York Times Company


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