The week’s most astounding developments from the neobiological frontier.

April 20, 2023

Mind-body connection mapped inside the brain

Researchers at Washington University in St. Louis have discovered that the mind and body are more closely intertwined than previously thought. Extensively mapping the brains of seven people using fMRI, they discovered that the motor cortex, which controls the movement of the hand and foot, has thin inter-effector regions not involved in movement but plugged into thinking, planning, and the control of involuntary bodily functions like blood pressure and heart rate. The work helps explain some baffling phenomena, they say in a press release, “such as why anxiety makes some people want to pace back and forth, why stimulating the vagus nerve, which regulates internal organ functions such as digestion and heart rate, may alleviate depression, and why people who exercise regularly report a more positive outlook on life.” Nature

In unrelated work, researchers at the University of Texas and Memorial Hermann Hospital in Houston have uncovered two distinct regions in the brain’s language network. One actively processes the meaning of individual words while the other decodes entire sentences. PNAS

Three-month old babies can count automatically in their sleep

At what early age do humans manifest the ability to count? One hypothesis suggests this happens automatically at quite a young age, as infants begin to analyze their environments both abstractly and quantitatively. To directly test this “core knowledge hypothesis,” scientists at the University of Paris-Saclay and New York University Grossman School of Medicine tracked the neural responses of sleeping 3-month-old infants with high-density electroencephalography (EEG). They found the babies have a genuine “number sense” and that their brains can automatically disentangle numerical and non-numerical information. But if this ability is innate, universal, and present at such an early stage in development, it raises the question: Why do pernicious, gendered beliefs about mathematics continue to persist and spread, causing many girls around the world to falsely believe they can’t do math as well as boys? Current Biology

Disrupted gut microbiome contributes to anorexia

Researchers at the University of Copenhagen and Herlev-Gentofte University Hospital in Denmark have discovered that people with anorexia have altered gut microbiome compositions with a higher likelihood of degrading chemical messengers that impact our brain function and mood. Looking at the microbiota compositions of 77 women with anorexia nervosa and 70 women who would be considered a healthy weight, they also found higher concentrations of blood metabolites known to induce satiety in women with anorexia. And transferring fecal samples from women with anorexia into mice induced aberrant energy metabolism and eating behaviors in the rodents—all of which suggests that a severely disrupted gut microbiome may contribute to some of the stages of anorexia. Nature Microbiology

Chord diagram showing significant associations between eating disorder scores denoted in blue and red text with bacterial structural variations listed in black—even after adjusting for age, BMI, smoking, and multiple drug intake. CC-BY 4.0

Mouse study pinpoints “height genes” more precisely

A mouse study focused on cartilage at the ends of bones called growth plates has shed light on the genetics of height. In humans as well as mice, growth plates harden as children grow. Looking at hundreds of millions of mouse cartilage cells, researchers at Boston Children’s Hospital and Harvard University identified 145 potential “height genes” they say are crucial for growth plate maturation and bone formation. Comparing that data to existing genome-wide association studies (GWAS) involving more than 5 million people, which have identified thousands of height-associated regions in the human genome, they precisely located human genes they say likely play a role in determining adult human height. Cell Genomics

Spaceflight tweaks the microbiome which weakens the bones

One of the well-known risks of spending too much time in zero gravity is osteoporosis and the loss of mineral density in the bones. Scientists at the University of California, Los Angeles and the Forsyth Institute in Cambridge, Massachusetts, have shown the effect may be driven by changes to the microbiome. They studied mice that were part of NASA’s Rodent Research-5 mission, flown to the International Space Station aboard a SpaceX rocket, and housed there for one month. They discovered the mice had an elevated abundance of Lactobacillus murinus and Dorea bacteria with enriched genes capable of producing metabolites and lactic acid, which can contribute to bone loss. This could lead to new ways to modulate the microbiome through drugs, dietary probiotics, or other means for long-haul spaceflight. Cell Reports

An immune cell that can get drugs into bones

A perennial problem of pharmaceutical development is the challenge of getting drugs across physiological barriers, like those that separate the brain or the bone marrow from the bloodstream. Now researchers at Zhejiang University in China have discovered how to get drugs across the blood-bone barrier using abundant immune cells in the body known as neutrophils. Typical adults make 100 billion neutrophil cells per day, and they naturally transit in and out of the bone marrow all the time. In mouse models, the researchers demonstrated the potential of neutrophils to deliver cabazitaxel—a bone cancer chemotherapy drug—and inhibit tumor growth. They also showed they could deliver teriparatide, a bone-mineral-density-increasing hormone, and alleviate signs of osteoporosis in mice. Nature Nanotechnology

Even the lowly worm gets the munchies

When humans consume cannabis, they often experience what scientists describe as “hedonic amplification of feeding”—that strong desire to eat rich, high-calorie, yummy foods more commonly known as the munchies. Researchers at the University of Oregon have discovered that this effect is surprisingly true of other species as well. They showed that when the nematode worm C. elegans is exposed to cannabinoid compounds from marijuana, they specifically increase their consumption of favored foods. What’s exciting for humans in this discovery is the possibility of a simple model to study the molecular basis of our brain’s system for regulating food choice. What’s exciting for the worm? Maybe a bit more Laffy Taffy and a few bootleg LPs of live Dead concerts from the 70s. Richmond Coliseum! Current Biology